Exploring the predictive power of jejunal microbiome composition in clinical and subclinical necrotic enteritis caused by Clostridium perfringens: insights from a broiler chicken model

BACKGROUND

Necrotic enteritis (NE) is a severe intestinal infection that affects both humans and poultry. It is caused by the bacterium Clostridium perfringens (CP), but the precise mechanisms underlying the disease pathogenesis remain elusive. This study aims to develop an NE broiler chicken model, explore the impact of the microbiome on NE pathogenesis, and study the virulence of CP isolates with different toxin gene combinations.

METHODS

This study established an animal disease model for NE in broiler chickens. The methodology encompassed inducing abrupt protein changes and immunosuppression in the first experiment, and in the second, challenging chickens with CP isolates containing various toxin genes. NE was evaluated through gross and histopathological scoring of the jejunum. Subsequently, jejunal contents were collected from these birds for microbiome analysis via 16S rRNA amplicon sequencing, followed by sequence analysis to investigate microbial diversity and abundance, employing different bioinformatic approaches.

RESULTS

Our findings reveal that CP infection, combined with an abrupt increase in dietary protein concentration and/or infection with the immunosuppressive variant infectious bursal disease virus (vIBDV), predisposed birds to NE development. We observed a significant decrease (p < 0.0001) in the abundance of Lactobacillus and Romboutsia genera in the jejunum, accompanied by a notable increase (p < 0.0001) in Clostridium and Escherichia. Jejunal microbial dysbiosis and severe NE lesions were particularly evident in birds infected with CP isolates containing cpa, netB, tpeL, and cpb2 toxin genes, compared to CP isolates with other toxin gene combinations. Notably, birds that did not develop clinical or subclinical NE following CP infection exhibited a significantly higher (p < 0.0001) level of Romboutsia. These findings shed light on the complex interplay between CP infection, the gut microbiome, and NE pathogenesis in broiler chickens.

CONCLUSION

Our study establishes that dysbiosis within the jejunal microbiome serves as a reliable biomarker for detecting subclinical and clinical NE in broiler chicken models. Additionally, we identify the potential of the genera Romboutsia and Lactobacillus as promising candidates for probiotic development, offering effective alternatives to antibiotics in NE prevention and control.

Development of a multivalent adjuvanted inactivated vaccine against variant arthrotropic avian reoviruses

Variant avian reoviruses (ARVs) are economically important emerging pathogens of poultry, which mainly affect young broiler chickens and cause significant production losses. Currently, there are no effective commercial vaccines available for control and prevention of emerging variant ARVs. In this study, monovalent inactivated adjuvated (20% Emulsigen D) broiler breeder vaccines containing antigens from ARV genotype cluster (C) group -2, -4, -5, or -6, and a multivalent vaccine containing antigens from all the four indicated genotypic cluster groups were developed and evaluated for their efficacy in protecting broiler progenies against homologous or heterologous ARV challenge. The use of monovalent or multivalent inactivated vaccines in a prime-boost immunization strategy induced the production of ARV specific antibodies in broiler breeders. The maternal antibodies were effectively transferred to broiler progenies. Broiler progenies obtained from immunized breeders demonstrated milder clinical symptoms and reduced gross and histopathological lesions after homologous ARV challenge. More severe gross and histological lesions were observed in challenged progenies from unvaccinated broiler breeders. However, cross protection was not observed when either of the monovalent-vaccine groups were challenged with a heterologous virus. In addition, the progenies from the unvaccinated ARV challenged control or heterologous ARV challenged vaccinated groups had significantly reduced body weight gain (p < 0.01) than the unchallenged-control, challenged-multivalent, or homologous ARV-challenged monovalent vaccine groups. However, homologous ARV challenged progenies in the multivalent or monovalent vaccine groups had similar body weight gain as the control unchallenged group with significantly reduced viral load (p < 0.01) in the gastrocnemius tendon tissue. This study indicates that broad-spectrum protection of broiler progenies from variant ARV infections is feasible through the development of multivalent vaccines after proper characterization, selection and incorporation of multiple antigens based on circulating ARV genotypes in targeted regions.

Upfront Osimertinib Alone vs. Osimertinib and Radiotherapy for the Treatment of EGFR-Positive NSCLC Brain Metastases: A Multi-Institutional Series

PURPOSE/OBJECTIVE(S)

Given the increased brain penetrance of osimertinib, the role of upfront radiotherapy (RT) has been questioned for the management of patients with EGFR+ NSCLC brain metastases (BM). We conducted a multi-institutional review of patients with EGFR+ NSCLC treated with upfront osimertinib or osimertinib in combination with RT for new or progressing BM.

MATERIALS/METHODS

Our multi-institutional analysis included 128 patients with 714 BM treated between 2013 and 2022. Two BM treatment groups were evaluated: (1) upfront osimertinib alone (n = 66) and (2) osimertinib + RT [whole brain radiation therapy or stereotactic/fractionated radiosurgery (SRS/FSRT)] prior or concurrently with osimertinib (n = 62)]; both groups began treatment within 2 months of BM diagnosis. Time-to-event analysis was conducted with the Kaplan-Meier (KM) method, and outcomes included intracranial control (IC) [both local and distant], intracranial progression free survival (IPFS), and overall survival (OS). A Cox proportional hazards model was utilized for multivariate analysis (MVA).

RESULTS

Median follow-up from BM diagnosis was 33.9 months (0.13-76.2 months). No differences in age (p = 0.46), sex (p = 0.72), DS-GPA (p = 0.08), KPS (p = 0.57), number of BM (p = 0.19) or volume of BM (p = 0.45), RT dose (p = 0.45), number of systemic metastases (p = 0.88), and patients symptomatic at presentation (p = 1.0) were noted. Prior treatment of BM was more common in the osimertinib + RT group (50% osimertinib + RT and 27% osimertinib; p = 0.01). The 12-month KM rates for osimertinib vs osimertinib + RT groups for IC were 72% vs 73% (p = 0.33); IPFS 53% vs 66% (p = 0.007); and OS 65% vs 80% (p = 0.025). On MVA, higher KPS (p = 0.002) was associated with increased OS and no extracranial metastasis with increased OS (p = 0.01) and IPFS (p = 0.001). MVA showed no association between osimertinib vs osimertinib + RT for IC, IPFS, or OS. Of the 66 patients treated with upfront osimertinib, 18 patients (27%) with 31 lesions eventually required RT for intracranial progression with the majority 72% being treated with SRS/FSRT at median of 13.5 months (1-22 months) following the start of osimertinib.

CONCLUSION

This study suggests that upfront osimertinib alone may provide sufficient intracranial control to allow RT to be deferred until further intracranial progression in select patients. Prospective trials are warranted to further guide treatment.

Comparison of Therapeutic Antibiotics, Probiotics, and Synthetic CpG-ODNs for Protective Efficacy Against Escherichia coli Lethal Infection and Impact on the Immune System in Neonatal Broiler Chickens

The poultry industry needs alternatives to antibiotics, as there are growing public concerns about the emergence of antimicrobial resistance owing to antimicrobial use in animal production. We have reported that the administration of neonatal chicks with synthetic DNA oligodeoxynucleotides containing unmethylated cytosine guanine dinucleotide (CpG) motifs (CpG-ODN) can protect against bacterial pathogens in chickens. The objective of this study was to compare the immunoprotective effects of CpG-ODN and probiotics against Escherichia coli infection vs. commonly used therapeutic antibiotics. Day-old broiler chicks were divided into five groups (n = 35/group; 30 for the challenge experiment and 5 for the flow cytometry analysis). The chicks in Group 1 received a single dose of CpG-ODN by the intramuscular route on day 4 (D4) posthatch (PH), and Group 2 received drinking water (DW) with a probiotic product (D1-D15 PH, DW). The Group 3 chicks received tetracycline antibiotics during D9-D13 in DW; the Group 4 chicks got sodium sulfamethazine on D9, D10, and D15 PH in DW; and the Group 5 chicks were administered intramuscular (IM) saline D4 PH, DW. We challenged all the groups (n = 30/group) with E. coli (1 × 10⁵ or 1 × 10⁶ colony-forming units/bird) on D8 PH through the subcutaneous route. Our data demonstrated that the CpG-ODNs, but not the probiotics, could protect neonatal broiler chickens against lethal E. coli septicemia, as would the tetracycline or sodium sulfamethazine. The flow cytometry analysis (n = 5/group) revealed enrichment of immune cells in the CpG-ODN group and a marked decrease in macrophages and T-cell numbers in antibiotics-treated groups, indicating immunosuppressive effects. Our data showed that, like therapeutic antibiotics, CpG-ODNs reduced clinical signs, decreased bacterial loads, and induced protection in chicks against E. coli septicemia. Unlike therapeutic antibiotics-induced immunosuppressive effects, CpG-ODN caused immune enrichment by increasing chicken immune cells recruitment. Furthermore, this study highlights that, although therapeutic antibiotics can treat bacterial infections, the ensuing immunosuppressive effects may negatively impact the overall chicken health.

Virulence of Emerging Arthrotropic Avian Reoviruses Correlates With Their Ability to Activate and Traffic Interferon-γ Producing Cytotoxic CD8+ T Cells Into Gastrocnemius Tendon

Newly emerging arthrotropic avian reoviruses (ARVs) are genetically divergent, antigenically heterogeneous, and economically costly. Nevertheless, the mechanism of emerging ARV-induced disease pathogenesis and potential differences in virulence between virus genotypes have not been adequately addressed. In this study, the life cycle of ARV, including the formation of cytoplasmic ARV neo-organelles, paracrystalline structures, and virus release mechanisms, were characterized in the infected host cell by transmission electron microscopy (TEM). In addition, progressive changes in the structure of infected cells were investigated by time-lapse and field emission scanning electron (FE-SE) microscopy. ARVs from the four genotypic cluster groups included in the study caused gross and microscopic lesions in the infected birds. Marked infiltration of γδT cells, CD4⁺ and CD8⁺ T lymphocytes were observed in ARV infected tendon tissues starting day 3 post-infection. The ARV variant from genotype cluster-2 triggered significantly high trafficking of IFN-γ producing CD8⁺ T lymphocytes in tendon tissues and concomitantly showed high morbidity and severe disease manifestations. In contrast, the ARV variant from genotype cluster-4 was less virulent, caused milder disease, and accompanied less infiltration of IFN-γ producing CD8⁺ T cells. Interestingly, when we blunted antiviral immune responses using clodronate liposomes (which depletes antigen-presenting cells) or cyclosporin (which inhibits cytokine production that regulates T-cell proliferation), significantly lower IFN-γ producing CD8⁺ T cells infiltrated into tendon tissues, resulting in reduced tendon tissues apoptosis and milder disease manifestations. In summary, these data suggest that the degree of ARV virulence and tenosynovitis/arthritis are potentially directly associated with the ability of the virus to traffic massive infiltration of cytotoxic CD8⁺ T cells into the infected tissues. Moreover, the ability to traffic cytotoxic CD8⁺ T cells into infected tendon tissues and the severity of tenosynovitis differ between variants from different ARV genotype cluster groups. However, more than one virus isolate per genotype group needs to be tested to further confirm the association of pathogenicity with genotype. These findings can be used to further examine the interaction of viral and cellular pathways which are essential for the pathogenesis of the disease at the molecular level and to develop effective disease control strategies.

Prosurvival IL-7-Stimulated Weak Strength of mTORC1-S6K Controls T Cell Memory via Transcriptional FOXO1-TCF1-Id3 and Metabolic AMPKα1-ULK1-ATG7 Pathways

CD8⁺ memory T (T_M) cells play a critical role in immune defense against infection. Two common γ-chain family cytokines, IL-2 and IL-7, although triggering the same mTORC1-S6K pathway, distinctly induce effector T (T_E) cells and T_M cells, respectively, but the underlying mechanism(s) remains elusive. In this study, we generated IL-7R-/and AMPKα1-knockout (KO)/OTI mice. By using genetic and pharmaceutical tools, we demonstrate that IL-7 deficiency represses expression of FOXO1, TCF1, p-AMPKα1 (T₁₇₂), and p-ULK1 (S₅₅₅) and abolishes T cell memory differentiation in IL-7R KO T cells after Listeria monocytogenesis rLmOVA infection. IL-2- and IL-7-stimulated strong and weak S6K (IL-2/S6K^strong and IL-7/S6K^weak) signals control short-lived IL-7R^-CD62L^-KLRG1⁺ T_E and long-term IL-7R⁺CD62L⁺KLRG1^- T_M cell formations, respectively. To assess underlying molecular pathway(s), we performed flow cytometry, Western blotting, confocal microscopy, and Seahorse assay analyses by using the IL-7/S6K^weak-stimulated T_M (IL-7/T_M) and the control IL-2/S6K^strong-stimulated T_E (IL-2/T_E) cells. We determine that the IL-7/S6K^weak signal activates transcriptional FOXO1, TCF1, and Id3 and metabolic p-AMPKα1, p-ULK1, and ATG7 molecules in IL-7/T_M cells. IL-7/T_M cells upregulate IL-7R and CD62L, promote mitochondria biogenesis and fatty acid oxidation metabolism, and show long-term cell survival and functional recall responses. Interestingly, AMPKα1 deficiency abolishes the AMPKα1 but maintains the FOXO1 pathway and induces a metabolic switch from fatty acid oxidation to glycolysis in AMPKα1 KO IL-7/T_M cells, leading to loss of cell survival and recall responses. Taken together, our data demonstrate that IL-7-stimulated weak strength of mTORC1-S6K signaling controls T cell memory via activation of transcriptional FOXO1-TCF1-Id3 and metabolic AMPKα1-ULK1-ATG7 pathways. This (to our knowledge) novel finding provides a new mechanism for a distinct IL-2/IL-7 stimulation model in T cell memory and greatly impacts vaccine development.

The Energy Sensor AMPKα1 Is Critical in Rapamycin-Inhibition of mTORC1-S6K-Induced T-cell Memory

Energy sensors mTORC1 and AMPKα1 regulate T-cell metabolism and differentiation, while rapamycin (Rapa)-inhibition of mTORC1 (RIM) promotes T-cell memory. However, the underlying pathway and the role of AMPKα1 in Rapa-induced T-cell memory remain elusive. Using genetic and pharmaceutical tools, we demonstrate that Rapa promotes T-cell memory in mice in vivo post Listeria monocytogenesis rLmOVA infection and in vitro transition of effector T (TE) to memory T (TM) cells. IL-2- and IL-2+Rapa-stimulated T [IL-2/T and IL-2(Rapa+)/T] cells, when transferred into mice, differentiate into short-term IL-7R-CD62L-KLRG1+ TE and long-lived IL-7R+CD62L+KLRG1- TM cells, respectively. To assess the underlying pathways, we performed Western blotting, confocal microscopy and Seahorse-assay analyses using IL-2/T and IL-2(Rapa+)/T-cells. We determined that IL-2(Rapa+)/T-cells activate transcription FOXO1, TCF1 and Eomes and metabolic pAMPKα1(T172), pULK1(S555) and ATG7 molecules and promote mitochondrial biogenesis and fatty-acid oxidation (FAO). We found that rapamycin-treated AMPKα-deficient AMPKα1-KO IL-2(Rapa+)/TM cells up-regulate transcription factor HIF-1α and induce a metabolic switch from FAO to glycolysis. Interestingly, despite the rapamycin treatment, AMPKα-deficient TM cells lost their cell survival capacity. Taken together, our data indicate that rapamycin promotes T-cell memory via transcriptional FOXO1-TCF1-Eomes programs and AMPKα1-ULK1-ATG7 metabolic axis, and that AMPKα1 plays a critical role in RIM-induced T-cell memory.

Assessment of neutrophil function in canine cancer patients undergoing chemotherapy and correlation with neutrophil numbers

Decreased neutrophil function following administration of chemotherapy has been reported in dogs with lymphoma. The first objective of our study was to determine if neutrophil oxidative burst and phagocytic activity are affected by chemotherapy 7 to 10 days following initiation of treatment in dogs with lymphoma and non-lymphoma malignancies. The second objective was to determine if there is a correlation between neutrophil numbers and neutrophil function before or after initiation of chemotherapy. Flow cytometric assessment of neutrophil oxidative burst and phagocytosis following stimulation with Escherichia coli was performed in 9 dogs diagnosed with lymphoma and 17 non-lymphoma tumor-bearing dogs pre- and post-chemotherapy, as well as 14 tumor-free control dogs. Spearman rank correlation was performed to determine if blood neutrophil numbers and neutrophil function were significantly correlated. Lymphoma patients showed significantly reduced percentage neutrophil oxidative burst post-chemotherapy compared to healthy controls as well as compared to pre-chemotherapy values (P = 0.0022 and P = 0.0020, respectively). Lymphoma patients also exhibited significantly reduced neutrophil phagocytosis activity post-chemotherapy compared to controls and pre-chemotherapy values (P = 0.0016 and P = 0.014, respectively). Dogs with non-lymphoma malignancies also showed a significant decrease in both percentage oxidative burst and phagocytosis post-chemotherapy compared to pre-chemotherapy values (P = 0.00040 and P = 0.029, respectively). Neutrophil numbers and function were not significantly correlated. The results of the study suggest that chemotherapeutic treatment decreases neutrophil oxidative burst and phagocytic activity 7 to 10 days post-treatment in dogs with various malignancies. Furthermore, neutrophil numbers cannot be used to predict neutrophil function.

A new dynamic model of three cell interactions for CTL responses

The exact mechanisms of CD4 help in the generation of memory cytotoxic T lymphocytes (CTLs) remain largely illusive. We propose that dendritic cells (DCs) first interact with CD4⁺ T cells, resulting in DC licensing and CD4⁺ T-cell priming. Thereafter, CD8⁺ T cells can receive stimulatory signals from DC-CD4⁺ T-cell clusters and as well as individually from licensed DCs and primed CD4⁺ T cells.

The dynamics of molecular evolution of emerging avian reoviruses through accumulation of point mutations and genetic re-assortment

In the last decade, the emergence of variant strains of avian reovirus (ARV) has caused enormous economic impact in the poultry industry across Canada and USA. ARVs are non-enveloped viruses with ten segments of double-stranded RNA genome. So far, only six genotyping cluster groups are identified worldwide based on sequence analysis of the σC protein encoded by the S1 segment. In this study, we performed deep next generation whole-genome sequencing and analysis of twelve purified ARVs isolated from Saskatchewan, Canada. The viruses represent different genotyping cluster. A genome-wide sequence divergence of up to 25 per cent was observed between the virus isolates with a comparable and contrasting evolutionary history. The proportion of synonymous single-nucleotide variations (sSNVs) was higher than the non-synonymous (ns) SNVs across all the genomic segments. Genomic segment S1 was the most variable as compared with the other genes followed by segment M2. Evidence of positive episodic/diversifying selection was observed at different codon positions in the σC protein sequence, which is the genetic marker for the classification of ARV genotypes. In addition, the N-terminus of σC protein had a persuasive diversifying selection, which was not detected in other genomic segments. We identified only four ARV genotypes based on the most variable σC gene sequence. However, a different pattern of phylogenetic clustering was observed with concatenated whole-genome sequences. Together with the accumulation of point mutations, multiple re-assortment events appeared as mechanisms of ARV evolution. For the first time, we determined the mean rate of molecular evolution of ARVs, which was computed as 2.3 × 10^-3 substitution/site/year. In addition, widespread geographic intermixing of ARVs was observed between Canada and USA, and between different countries of the world. In conclusion, the study provides a comprehensive analysis of the complete genome of different genotyping clusters of ARVs including their molecular rate of evolution and spatial distribution. The new findings in this study can be utilized for the development of effective vaccines and other control strategies against ARV-induced arthritis/tenosynovitis in the poultry industry worldwide.

Soil surfactants influence fungicide movement in United States Golf Association putting green soil

The management of root and crown diseases of turfgrasses is challenging. To manage these diseases, golf course superintendents and other turfgrass managers often spray fungicides at a high carrier volume and irrigate after application to move fungicides into the root zone. Furthermore, previous research has demonstrated that soil surfactants can increase fungicide movement and distribution in soil. Two laboratory experiments were conducted using lysimeters, which were coated with sand on their inner walls to prevent preferential flow and contained 90/10% sand/peat moss (v/v), to determine the effects of soil surfactants on movement of selected fungicides in soil. The soil surface in the first experiment was treated three times at 2-wk intervals with one of three soil surfactants: Aquifer (propoxylated polyethylene glycols), Fleet (polyoxyalkylene polymers), and Revolution (modified alkylated polyol). The soil in the second experiment was treated with only Revolution four times at 2- to 3-wk intervals. Immediately after the final surfactant application, soil columns were treated with ¹⁴ C-labeled fungicide. ¹⁴ C-Myclobutanil was applied in the first experiment, and ¹⁴ C-azoxystrobin and ¹⁴ C-propiconazole were applied in the second experiment. In the first experiment, 14 percent units more of the recovered ¹⁴ C-myclobutanil was detected in the 5- to 7.6-cm sampling depth, and >4 percent units more was detected in the 7.6- to 10.2-cm depth after soil surfactant application compared with the fungicide-alone treatment. Each soil surfactant also yielded >28% more leachate than the nontreated control. In the second experiment, the total recovered ¹⁴ C-azoxystrobin and ¹⁴ C-propiconazole in the 7.6- to 10.2-cm depth increased by 2.8 and 1.9 percent units, respectively, compared with soil treated with fungicide alone. These data indicate that soil surfactant inclusion may increase fungicide distribution in soil, which may enhance the efficacy of fungicides in suppressing root and crown diseases.

Non-viable chicken embryos: an overlooked niche harbouring a significant source of multidrug resistant bacteria in the poultry production

Antimicrobial resistance (AMR) is a global issue, posing a grave threat to the public, animal, and environmental health. The AMR surveillance at the level of the hatchery is crucial to develop an AMR control strategy in the poultry industry. The objective of this study was to investigate the AMR profiles of bacteria isolated from yolk material of non-viable broiler chicken embryos at hatch from commercial hatcheries in western Canada. Antimicrobial susceptibility testing was done using the Kirby–Bauer disk diffusion method focusing on Escherichia coli (n = 170) and Enterococcus (n = 256) species, which are commonly used as indicators of AMR evolution. E. coli isolates were resistant to tetracycline, ampicillin, amoxycillin-clavulanic acid, triple sulpha, ceftiofur, gentamycin, and spectinomycin at the rate of 52.9%, 50.6%, 40.0% 31.8%, 29.4%, 29.4%, 21.8% respectively. Among those, 37.1% of E. coli were multidrug resistant. The descending order of antimicrobial resistance of E. faecalis was; tetracycline (61.9%), ceftiofur (46.2%), bacitracin (43.9%), erythromycin (31.4%) and tylosin (27.4%). Multidrug resistance was detected in 40.4% of E. faecalis isolates, and 85.7% of E. faecium isolates. To the best of our knowledge, this is the first report on AMR surveillance of non-viable chicken embryos. Overall, the present study revealed that non-viable chicken embryos, an overlooked niche for AMR surveillance, harbour multidrug-resistant E. coli, and enterococci that can be a substantial source of superbugs in the environment. Our data also highlight the urgency of including non-viable chicken embryos in AMR surveillance programme to understand AMR dissemination and its control.

Intrapulmonary Delivery of CpG-ODN Microdroplets Provides Protection Against Escherichia coli Septicemia in Neonatal Broiler Chickens

Synthetic oligodeoxynucleotides (ODN) containing unmethylated cytosine phosphodiester guanine (CpG) motifs (CpG-ODN) are effective immunostimulatory agents against a variety of viral, bacterial, and protozoan diseases in different animals including poultry. We have recently demonstrated that in ovo injection of CpG-ODN confers protection in neonatal chickens against bacterial septicemias. The objective of this study was to investigate the effectiveness of needle-free intrapulmonary (IPL) delivery of CpG-ODN microdroplets against Escherichia coli infection in neonatal chicks. In the present study, we used 880 chicks in total keeping 40 chicks per group. Chicks were delivered CpG-ODN or saline by IPL at the day 1 of hatch. Three days later, chicks were challenged with two doses (1 × 10⁴ CFU, n = 20 or 1 × 10⁵ CFU, n = 20) of E. coli. Chicks treated with CpG-ODN by the IPL route had significantly lower clinical signs and bacterial load compared to the group treated with saline ( P < 0.05). CpG-ODN-treated groups were significantly protected against E. coli septicemia. We observed dose- and exposure time-dependent immunoprotective effects of IPL CpG-ODN in chicks. We found that IPL delivery of CpG-ODN can induce protective immunity as early as 6 hr that remains effective at least until day 5 post-treatment. Moreover, there were no adverse effects of IPL delivery of CpG-ODN on growth or mortality up to 42 days of age. Based on these findings, it can be suggested that CpG-ODN delivery by IPL route can be a promising alternative to antibiotics for inducing protective immunity in chicks during the critical first week of neonatal life.

Abstract OT2-04-05: Phase II trial of pre-operative stereotactic ablative radiotherapy (SABR) in early-stage breast cancer

Background:

Post-operative accelerated partial breast irradiation (APBI) has demonstrated efficacy in preventing in-breast tumor recurrence. Pre-operative administration of APBI may be advantageous as an intact breast tumor is smaller than its corresponding lumpectomy cavity, is easier to distinguish on treatment-planning images, and results in smaller and more accurately delineated target volumes. Pre-operative APBI may reduce the incidence of positive margins following breast-conserving surgery (BCS). Investigation is needed in the correlation of MR imaging with pathologic response 6 weeks after SABR. Also, evidence suggests that SABR induces immune activation in the tumor microenvironment; evaluation of excised tumor tissue will give insight into these processes.

Trial Design:

Treatment Planning and Delivery: CT simulation and treatment are performed in the prone position. Diagnostic MRI is fused to planning CT. GTV is delineated on registered breast MRI and includes the intact breast tumor. CTV is 15mm expansion of GTV. PTV is 3 mm expansion of CTV. VMAT or IMRT are permitted. Daily image-guidance aligning to tumor and biopsy-fiducial is mandatory. All subjects undergo pre-operative SABR to 28.5 Gy in 3 fractions of 9.5 Gy on different days separated by ≤48 hours. CTCAE v4 is used to assess toxicity 4-5 weeks after SABR. Pre-operative diagnostic MRI is performed 5-6 weeks following SABR. Imaging parameters to be evaluated include changes in tumor size, enhancement, and tumor margin description. BCS will be 6-8 weeks following SABR.

Tissue pathology: Margin status and degree of pathologic response are recorded from breast-conserving excisions, specimens are archived for future analysis.

Eligibility Criteria:

Inclusion criteria are women age ≥50 with biopsy proven invasive breast adenocarcinoma with tumor size ≤2cm on MRI, cN0 M0, ER+/HER2-, without history of invasive malignancy or prior breast/thoracic radiotherapy.

Exclusion criteria are active scleroderma or lupus erythematosus with skin involvement, MRI defined tumor within 10 mm of skin, implanted hardware prohibiting appropriate treatment planning or delivery, neoadjuvant chemotherapy, carrier of BRCA1 or 2 gene mutation, pregnancy.

Specific Aims:

The primary endpoint is pathologic complete response (pCR) in the breast tumor, secondary endpoints are incidence of adequate surgical margins (defined as “no tumor on ink”) and MRI response following SABR. Analyses of tumor immune response and microenvironment on pathologic specimens following SABR will also be performed.

Statistical Methods:

Fisher's exact test will be performed to examine associations between patient/tumor characteristics and pCR and surgical margins; these associations will be explored with multivariable logistic and linear regressions.

Accrual:

Present accrual is 9 subjects.

Expected accrual is 22 subjects; if ≥3 pCR are noted in the initial cohort, accrual will be expanded to 40 subjects.

Citation Format: Liveringhouse CL, Diaz R, Ahmed KA, Lee MC, Czerniecki B, Laronga C, Khakpour N, Weinfurtner RJ, Rosa M, Montejo ME. Phase II trial of pre-operative stereotactic ablative radiotherapy (SABR) in early-stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-05.

Abstract P4-08-15: Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence

Background:

The presence of TILs has been correlated with clinical outcomes and response to therapy in breast cancer. However, evaluation of TILs in breast cancer has largely been based on pathologic examination of tumor samples. Here, we report the relationship between invasive breast cancer locoregional recurrence (LRR) and the presence of TILs estimated by transcriptomic analysis with the deconvolution algorithm CIBERSORT.

Methods:

Patients were identified from an IRB-approved prospective tissue collection protocol at one academic institution and two community hospitals. 526 primary breast tumor samples were identified and gene expression profiling was assessed with high density Affymetrix microarray chips. Proportions of 22 different TIL types in samples were inferred based on the CIBERSORT algorithm, which uses gene expression data to estimate TIL presence. TIL presence was determined by dichotomization at the level of the first quartile among all samples (&gt;Q1=TIL presence). Patient characteristics and clinical outcomes were obtained by chart review. Time to event analysis was performed using Kaplan Meier (KM) estimates and the log-rank test. Associations between patient factors, tumor factors, TIL presence, and LRR were explored with univariable (UVA) and multivariable (MVA) analyses. Factors significant on UVA (p&lt;0.10) were included on MVA. P&lt;0.05 was considered statistically significant on MVA.

Results:

526 women with invasive breast cancer and available genomic profiling were retrospectively identified for analysis. Median age at diagnosis was 58 years. 70% of tumors were Stage I-II. 69% were luminal subtypes and 17% were triple negative. 37% received mastectomy, 25% received mastectomy + radiation, and 32% received breast conserving therapy. 64% received chemotherapy, and 62% received hormonal therapy. Median follow-up was 74.4 months. There were 61 LRRs. We found significant differences in time to LRR when comparing presence vs. no presence of resting memory CD4+ T-cells (RMCD4+) (p=0.01), activated natural killer cells (ANK) (p=0.003), and neutrophils (PMNs) (p=0.03). On UVA, factors associated with LRR were patient age at diagnosis (p=0.009), pathologic T stage (p=0.045), Estrogen receptor status (p=0.03), biologic subtype (p=0.01), lymphovascular invasion (LVI) (p=0.018), positive margins (p&lt;0.0001), receipt of hormonal therapy (0.014), and presence of tumor infiltrating RMCD4+ (p=0.012), ANK (p=0.0004), and PMNs (p=0.033). On MVA, factors remaining significant were LVI (HR 2.16 CI 1.13-4.13, p=0.011), positive margins (HR 4.36 CI 1.57-12.11, p=0.018), receipt of hormonal therapy (HR 0.31 CI 0.12-0.77, p=0.042), and presence of RMCD4+ (HR 0.48 CI 0.26-0.88, p=0.017), ANK (HR 0.43 CI 0.23-0.83, p=0.012), and PMNs (HR 2.15 CI 1.02-4.53, p=0.043).

Conclusion:

In this study of 526 women with invasive breast cancer, we identified that enrichment of certain TILs is associated with LRR. These results suggest genomic-based assays of TIL presence may be useful to predict LRR in invasive breast cancer.

Citation Format: Liveringhouse CL, Grass GD, Figura NB, Mills MN, Purcell JD, Rosensweig SR, Blumencranz PW, Allen KG, Ahmed KA, Harrison LB, Torres-Roca JF, Robinson TJ, Diaz R. Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-15.

Synthetic CpG-ODN rapidly enriches immune compartments in neonatal chicks to induce protective immunity against bacterial infections

Oligodeoxynucleotides containing CpG motifs (CpG-ODN) induce innate immunity against bacterial infections. Despite recent advances, how CpG-ODN alone protects against bacterial infections remained elusive. Here, we report for the first time, to our knowledge, that CpG-ODN orchestrates anti-microbial protective immunity by inducing a rapid enrichment of various immune compartments in chickens. In this study, eighteen-day-old embryonated eggs were injected with either 50 µg of CpG-ODN or saline (~n = 90 per group). In the first experiment, four days after CpG-ODN treatment, chicks were challenged subcutaneously with a virulent strain of Escherichia coli (E. coli) and mortality was monitored for 8 days. We found significant protection, and reduced clinical scores in CpG-ODN treated chicks. To gain insights into mechanisms of protection induced by CpG-ODN, first we investigated cytokine expression kinetics elicited by CpG-ODN. The spleen and lung were collected from embryos or chicks (n = 3-4 per group) at 10 time points post-CpG-ODN inoculation. Multiplex gene analysis (interleukin (IL)-1, IL-4, IL-6, IL-10, IL-18, interferon (IFN)-γ, IFN-α, and lipopolysaccharide induced tumor necrosis factor (LITAF), revealed a significantly higher expression of pro-inflammatory cytokines following CpG-ODN treatment compared to the saline controls. In our study, LITAF stands out in the cytokine profiles of spleen and lungs, underscoring its role in CpG-ODN-induced protection. The third experiment was designed to examine the effects of CpG-ODN on immune cell populations in spleen, lungs, and thymus. Flow cytometry analysis was conducted at 24, 48 and 72 hrs (thymus only collected at 72 hr) after CpG-ODN administration to examine the changes in CD4⁺ and CD8⁺ T-cell subsets, monocyte/macrophage cell populations and their expression of maturation markers (CD40 and CD86). Flow cytometry data indicated a significant enrichment of macrophages, CD4⁺ and CD8⁺ T-cell subsets in both spleen and lungs of CpG-ODN treated embryos and chicks. Macrophages in spleen and lungs showed an upregulation of CD40 but not CD86, whereas thymocytes revealed significantly high CD4 and CD8 expression. Overall, the present study has demonstrated that CpG-ODN provides protection in neonatal chicks against E. coli infection not only by eliciting cytokine responses and stimulating immune cells but also through enriching immunological niches in spleen and lungs.

Multiple effects of CD40-CD40L axis in immunity against infection and cancer

CD8⁺ cytotoxic T lymphocyte (CTL) protects against infection and cancer cells. Understanding the mechanisms involved in generation and maintenance of effective CTL responses is essential for improving disease therapy and vaccine protocols. During CTL responses, immune cells encounter several tightly regulated signaling pathways; therefore, in such a dynamic process, proper integration of critical signals is necessary to orchestrate an effective immune response. In this review, we have focused on CD40-CD40L interactions (a key signal) in the regulation of dendritic cell (DC)-T cell (CD4⁺ T and CD8⁺ T) cross-talk, rescuing CTL exhaustion, and converting DC tolerization. We have also highlighted the knowledge gap and future directions to design immunotherapies.

Phenotypic, genotypic and antigenic characterization of emerging avian reoviruses isolated from clinical cases of arthritis in broilers in Saskatchewan, Canada

In recent years, emerging strains of pathogenic arthrogenic avian reovirus (ARV) have become a challenge to the chicken industry across USA and Canada causing significant economic impact. In this study, we characterized emerging variant ARV strains and examined their genetic and antigenic relationship with reference strains. We isolated 37 emerging variant ARV strains from tendons of broiler chickens with clinical cases of arthritis/tenosynovitis at commercial farms in Saskatchewan, Canada. Viral characterization using immunocytochemistry, gold-immunolabeling and electron microscopy revealed distinct features characteristic of ARV. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the viral Sigma C gene revealed genetic heterogeneity between the field isolates. On phylogenetic analyses, the Sigma C amino acid sequences of the isolates were clustered into four distinct genotypic groups. These ARV field strains were genetically diverse and quite distant from the vaccine and vaccine related field strains. Antibodies produced against a commercial Reo 2177 ® vaccine did not neutralize these variants. Moreover, structure based analysis of the Sigma C protein revealed significant antigenic variability between the cluster groups and the vaccine strains. To the best of our knowledge, this is the first report on the genetic, phenotypic and antigenic characterization of emerging ARVs in Canada.

mTORC1 regulates mannose-6-phosphate receptor transport and T-cell vulnerability to regulatory T cells by controlling kinesin KIF13A

Mannose-6-phosphate receptor (M6PR) that facilitates cellular uptake of M6P-bearing proteins, including serine-protease granzyme-B (Gzm-B) has an important role in T-cell activation, migration and contraction. However, molecular mechanisms controlling M6PR expression in T cells remain poorly understood. Here, we show that M6PR expression on T cells is distinctively controlled by two common γ-chain cytokines interleukin-2 (IL-2) and IL-7, and the differential M6PR expression is not caused by an altered synthesis of M6PR protein, but is a result of distinct regulation of kinesin-3 motor-protein KIF13A that transport M6PR onto cell surfaces. Using signaling pathway-specific inhibitors, we determine that IL-2 and IL-7 distinctly regulate KIF13A and β1-adaptin and cell-surface M6PR by controlling a kinase mammalian target of rapamycin complex-1 (mTORC1). Inflammatory cytokine IL-2 and prosurvival cytokine IL-7 induce strong and weak activation of mTORC1, leading to up- and downregulation of motor-protein KIF13A and KIF13A-motorized M6PR on T cells, and formation of IL-2 and IL-7 effectors with M6PR^high and M6PR^low cell-surface expression, respectively. Inhibition of mTORC1 by rapamycin reduces T-cell expression of KIF13A and cell-surface M6PR, and increases T-cell survival in Listeria monocytogenes-infected mice. Using regulatory T (T_reg)-cell-enriched mouse tumor model, we determine that M6PR^high IL-2 effectors but not M6PR^low IL-7 effectors adoptively transferred into tumors are vulnerable to T_reg Gzm-B-mediated cell apoptosis. Inhibition of mTORC1 or small interfering RNA-mediated knockdown of KIF13A or M6PR renders IL-2 effectors refractory to T_reg Gzm-B lethal hit. Overall, our data offer novel mechanistic insights into T-cell M6PR regulation, and T_reg-resistant/T_reg-susceptible phenomenon. Furthermore, regulation of T-cell fate vis-à-vis T_reg suppression via the mTORC1-KIF13A-M6PR axis provides a proof of concept for therapeutic strategies to target cancer, infectious and autoimmune diseases.

Immunogenicity and protective efficacy of virus-like particles and recombinant fiber proteins in broiler-breeder vaccination against fowl adenovirus (FAdV)-8b

Inclusion body hepatitis (IBH) is an economically important diseases in broiler chicken industry. Several serotypes of fowl adenovirus (FAdV) can cause IBH, among them, serotype FAdV-8b is associated with the majority of the IBH cases in Canada. Here, we evaluated FAdV-8b virus-like particles (VLPs) and recombinant FAdV-8b fiber proteins (expressed in E. coli) as potential broiler-breeder vaccines against IBH. For assessing the immunogenicity of vaccines, we investigated both humoral and cellular immunity. The humoral immune response was evaluated by determining total IgY and virus-neutralizing antibody in serum at 14, 28, 35 and 60days post-immunization (dpi). We examined cellular immunity using flow cytometry by determining CD4:CD8 ratio change in peripheral blood after the booster vaccination. The protective effect of vaccines was tested by challenging 14day-old progeny (n=30/group) carrying maternal antibodies (MtAb) by challenging with virulent FAdV-8b virus (1×10⁷ TCID₅₀, FAdV-8b-SK). Although total IgY levels were comparable in all groups, the neutralizing antibody response in broiler-breeders at 35 and 60 dpi was significantly (p<0.05) higher those vaccinated with FAdV-8b VLPs followed by FAdV-8b fiber compared to fiber-knob. Moreover, vaccines comprised of FAdV-8b VLPs and FAdV-8b fiber rather than FAdV-8b fiber-knob efficiently elicited the cell-mediated immune response as evidenced by a statistically significant (p<0.05) CD8⁺ T-cell proliferative response in broiler-breeders four days after the booster vaccination. Unlike FAdV-8b fiber-knob, FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders were able to transfer a substantial amount (28.4±9%) of MtAb to their progeny. Challenge revealed that MtAb provided 100% and 82.7% protection in progeny hatched from FAdV-8b VLPs, and FAdV-8b fiber vaccinated broiler-breeders, respectively. Collectively, our data suggest that FAdV-8b subunit vaccine-induced MtAb efficiently protected progeny against clinical IBH and broiler-breeder vaccination with subunit vaccines is a potential approach to protect against IBH.

Enhanced suppression of polyclonal CD8+25+ regulatory T cells via exosomal arming of antigen-specific peptide/MHC complexes

Compared with CD4⁺25⁺ regulatory T cells (T_regs), the mechanisms for natural, polyclonal CD8⁺25⁺ T_reg immune suppression have been significantly less studied. We previously showed that polyclonal T cells can acquire antigen-specific targeting activity through arming with exosomal peptide-MHC (pMHC). In this study, we assessed the suppressive effect of CD8⁺25⁺ T_regs or CD8⁺25⁺ T_regs armed with ovalbumin (OVA)-specific exosomes on other immune cells and OVA-specific dendritic cell (DC_OVA)-stimulated antitumor immunity. We demonstrate that CD8⁺25⁺ T_regs inhibit T cell proliferation in vitro in a cell contact-dependent fashion but independent of the expression of immunosuppressive IL-10, TGF-β, and CTLA-4. CD8⁺25⁺ T_regs anergize naïve T cells upon stimulation by up-regulating T cell anergy-associated Egr2 and down-regulating IL-2 production. T_regs also anergize DCs by preventing DC maturation through the down-regulation of Ia^b, CD80, CD86, and inflammatory cytokines, leading to defects in T cell stimulation. Moreover, CD8⁺25⁺ T_regs inhibit CTLs through inducing CTL death via perforin-mediated apoptosis and through reducing effector CTL cytotoxic activity via down-regulating CTL perforin-production and degranulation. In addition, we show that CD8⁺25⁺ T_regs suppress DC_OVA-stimulated CTL responses in priming and effector phases and inhibit immunity against OVA-expressing CCL_OVA lung cancer. Remarkably, polyclonal CD8⁺25⁺ T_regs armed with OVA-specific exosomal pMHC class-II (pMHC-II), or pMHC class-I (pMHC-I) complexes exert their enhanced inhibition of CTL responses in the priming and the effector phases, respectively. Taken together, our investigation reveals that assigning antigen specificity to nonspecific polyclonal CD8⁺25⁺ T_regs for enhanced immune suppression can be achieved through exosomal pMHC arming. This principle may have a great effect on T_reg-mediated immunotherapy of autoimmune diseases.

Modified live infectious bursal disease virus (IBDV) vaccine delays infection of neonatal broiler chickens with variant IBDV compared to turkey herpesvirus (HVT)-IBDV vectored vaccine

Chickens are commonly processed around 35-45days of age in broiler chicken industry hence; diseases that occur at a young age are of paramount economic importance. Early age infection with infectious bursal disease virus (IBDV) results in long-lasting immunosuppression and profound economic losses. To our knowledge, this is the first study comparing the protection efficacy of modified live (MdLV) IBDV and herpesvirus turkey (HVT)-IBDV vaccines against early age variant IBDV (varIBDV) infection in chicks. Experiments were carried out in IBDV maternal antibody (MtAb) positive chicks (n=330), divided into 6 groups (n=50-60/group), namely Group 1 (saline), Group 2 (saline+varIBDV), Group 3 (HVT-IBDV), Group 4 (HVT-IBDV+varIBDV), Group 5 (MdLV) and Group 6 (MdLV+varIBDV). HVT-IBDV vaccination was given via the in ovo route to 18-day-old embryonated eggs. MdLV was administered via the subcutaneous route in day-old broilers. Group 2, Group 4 and Group 6 were orally challenged with varIBDV (SK-09, 3×10³ EID₅₀) at day 6 post-hatch. IBDV seroconversion, bursal weight to body weight ratio (BBW) and bursal histopathology were assessed at 19 and 35days of age. Histopathological examination at day 19 revealed that varIBDV-SK09 challenge caused severe bursal atrophy and lower BBW in HVT-IBDV but not in MdLV vaccinated chicks. However by day 35, all challenged groups showed bursal atrophy and seroconversion. Interestingly, RT-qPCR analysis after varIBDV-SK09 challenge demonstrated an early (9days of age) and significantly high viral load (∼5744 folds) in HVT-IBDV vaccinated group vs unvaccinated challenged group (∼2.25 folds). Furthermore, flow cytometry analysis revealed inhibition of cytotoxic CD8⁺ T-cell response (CD44-downregulation) and decreased splenic lymphocytes counts in chicks after HVT-IBDV vaccination. Overall, our data suggest that MdLV delays varIBDV pathogenesis, whereas, HVT-IBDV vaccine is potentially immunosuppressive, which may increase the risk of early age varIBDV infection in broilers.

A 5-year study of the incidence and economic impact of variant infectious bursal disease viruses on broiler production in Saskatchewan, Canada

While the prevalence of infectious bursal disease virus (IBDV) on chicken farms in some provinces of Canada has been documented, the economic impact of variant IBDV infection on the broiler chicken industry in Saskatchewan has not. The objectives of this study were to identify the variant strains of IBDV circulating on Saskatchewan chicken farms and evaluate their economic impact on broiler production. Infection due to IBDV was detected in 43% of Saskatchewan chicken farms, with variant strains detected in infected birds closely related predominantly to NC171, 586, and Delaware-E. Infected flocks showed an IBDV antibody titer of 4236 geometric mean (GM), whereas an antibody titer of 157 GM was measured in uninfected flocks. Infected flocks had very low (0.06) bursa-to-body-weight (BBW) ratio (an indicator of immunity) compared to high BBW ratio (0.17) in uninfected flocks, which suggests a significant immunosuppression in the former. Flocks positive for IBDV had mean mortality of 8.6% and mean condemnation of 1.5%. In contrast, mean mortality in uninfected flocks was 6.1% and mean condemnation was 1.1%. The live market weight per grow area at 37 d of age was 29.3 kg/m² in infected flocks and 34.0 kg/m² in flocks without IBDV infection. Flock mortality and condemnation rate were positively correlated with IBDV infection, whereas low BBW ratio was inversely correlated, as expected. Overall, IBDV-infected flocks had higher mortality, bursal atrophy, poorer feed conversion ratio (FCR), and decreased meat production. Our data suggest that the broiler chicken industry in Saskatchewan loses 3.9 million kilograms of meat production per year due to variant IBDV strains.

Clinical outcomes of melanoma brain metastases treated with stereotactic radiosurgery and anti-PD-1 therapy, anti-CTLA-4 therapy, BRAF/MEK inhibitors, BRAF inhibitor, or conventional chemotherapy

BACKGROUND

The effect of immunologic and targeted agents on intracranial response rates in patients with melanoma brain metastases (MBMs) is not yet clearly understood. This report analyzes outcomes of intact MBMs treated with single-session stereotactic radiosurgery (SRS) and anti-PD-1 therapy, anti-CTLA-4 therapy, BRAF/MEK inhibitors(i), BRAFi, or conventional chemotherapy.

PATIENTS AND METHODS

Patients were included if MBMs were treated with single-session SRS within 3 months of receiving systemic therapy. The primary end point of this study was distant MBM control. Secondary end points were local MBM control defined as a >20% volume increase on follow-up MRI, systemic progression-free survival, overall survival (OS) from both SRS and cranial metastases diagnosis, and neurotoxicity. Images were reviewed alongside two neuro-radiologists at our institution.

RESULTS

Ninety-six patients were treated to 314 MBMs over 119 SRS treatment sessions between January 2007 and August 2015. No significant differences were noted in age (P = 0.27), gender (P = 0.85), treated gross tumor volume (P = 0.26), or the diagnosis-specific graded prognostic assessment (P = 0.51) between the treatment cohorts. Twelve-month Kaplan-Meier (KM) distant MBM control rates were 38%, 21%, 20%, 8%, and 5% (P = 0.008) for SRS with anti-PD-1 therapies, anti-CTLA-4 therapy, BRAF/MEKi, BRAFi, and conventional chemotherapy, respectively. No significant differences were noted in the KM local MBM control rates among treatment groups (P = 0.25). Treatment with anti-PD-1 therapy, anti-CTLA-4 therapy, or BRAF/MEKi significantly improved OS on both univariate and multivariate analyses when compared with conventional chemotherapy.

CONCLUSION

In our institutional analysis of patients treated with SRS and various systemic immunologic and targeted melanoma agents, significant differences in distant MBM control and OS are noted. Prospective evaluation of the potential synergistic effect between these agents and SRS is warranted.

Circulating strains of variant infectious bursal disease virus may pose a challenge for antibiotic-free chicken farming in Canada

Antibiotic-free and safe animal products are most desirable among consumers. However, ensuring safe poultry products is a challenging task when the chicken immune system is compromised. Infectious bursal disease virus (IBDV) causes immunosuppression and predisposes chickens to secondary infections. Breeder vaccination against IBDV is routinely practiced for producing chicks with maternally-derived antibody (MAb) to prevent infection in newly hatched chicks. The majority of IBDV circulating in Canadian farms are variant strains (vIBDV). Whether circulating vIBDV strains are immunosuppressive in chicks or are amenable to current vaccine regimens has not previously been tested through challenge studies. In this study, one-day-old broiler chicks (n=240) carrying MAb were obtained from broiler breeders vaccinated with commercial IBDV vaccines. In the first set of experiments (n=40/group), at six days post-hatch, one group was challenged with a Canadian field isolate, vIBDV (strain-SK09) (3×10(3) EID50). The second and the third groups (controls) were inoculated with non-immunosuppressive IBDV D-78 (10×10(3) TCID50) and saline, respectively. Histopathological examination on days 14 and 30 post-challenge revealed that despite the high level of MAb, vIBDV (SK09) caused severe bursal damage in chicks. Another set of experiments with treatment groups as above, demonstrated that pre-exposure of chicks with vIBDV (SK09) caused immunosuppression resulting in significantly higher mortality and disease severity in chicks challenged with a virulent strain of Escherichia coli (E. coli). Our data provide evidence that IBDV strains circulating in Canada are immunosuppressive, not amenable to current anti-IBDV vaccination strategy, and a potential threat to antibiotic-free chicken farming.

Abstract P3-12-03: Utilizing the genomically adjusted dose (GAD) to personalize radiotherapy in adjuvant breast cancer management

Background: We have previously validated a multi-gene model of tumor radiosensitivity (RSI) with validation in multiple independent cohorts including breast, rectal, esophageal, head and neck, glioblastoma, and prostate malignancies. Utilizing the linear quadratic model and RSI, we derived an expression for the genomically adjusted dose (GAD) to model radiation dose effect for individual patients.

Methods: As RSI models the surviving fraction of cells at 2 Gy (SF2), we are able to derive a patient specific alpha. These terms were used in the linear quadratic model to calculate a GAD to model radiation effect and its association with local control. A higher GAD implies a higher predicted radiation therapy effect. Clinical and array-based gene expression were obtained from 75 ER negative patients from the Netherlands Cancer Institute (NKI) and the Institut Curie treated with breast conservation therapy.

Results: Median follow-up for all patients was 10 years with a median age of 42 years (range: 23-50 years). Adjuvant radiation dose to the whole breast was 50 Gy (range: 45-55 Gy). When assessing local recurrence on multivariate analysis, we found GAD to be a significant predictor of local recurrence when dichotomized at the median (GAD-low vs GAD-high Hazard Ratio (HR) 4.5; 95% CI 1.7-13.5; p=0.0031). GAD was also significant per unit change (HR 0.91; 95% CI 0.83-0.99; p=0.021). We then modeled GAD for an escalated dose up to 60 Gy and found an additional 48% of GAD-low patients could achieve a GAD-high with dose escalation.

Conclusions: We found GAD to be significantly correlated with local control following breast conservation therapy. Modeling dose escalation with GAD, we identified a select population of patients whom we hypothesize may benefit from genomically guided increased dose in the adjuvant setting. This population may represent a cohort for future clinical trial enrollment.

Citation Format: Ahmed KA, Venkat PS, Scott JG, Diaz RJ, Fulp WJ, Torres-Roca JF. Utilizing the genomically adjusted dose (GAD) to personalize radiotherapy in adjuvant breast cancer management. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-12-03.

Abstract P3-12-04: The genomically adjusted radiation dose (GAD) and its association with distant metastases in breast cancer: A feasible approach to precision medicine in radiation oncology

Background: Clinical validation studies in over 2,200 patients across 8 different disease sites, including breast cancer, have shown the radiosensitivity index (RSI), a gene expression signature, predicts outcomes in patients treated with radiation. We hypothesize that an approach to personalize radiation dose could be developed by integrating RSI into the linear quadratic model of dose and fractionation.

Methods: Utilizing the linear quadratic model and RSI, we derived an expression for the genomically adjusted dose (GAD) to model radiation dose effect for individual patients. A higher GAD implies a higher predicted radiation therapy effect. GAD was evaluated as a predictor of clinical outcome in two independent datasets of breast cancer patients treated with surgery and radiation. The association between GAD and distant-metastasis free survival (DMFS) and relapse-free survival (RFS) using univariate (UVA) and multivariate (MVA) Cox proportional hazard models was assessed. Clinical and array-based gene expression were obtained from two independent, previously described cohorts from the Karolinska Institutet and Erasmus University Medical Center.

Results: Full radiation treatment details were available for 263 patients in the Erasmus dataset, median follow-up 60 months. GAD-low patients (&lt;75% GAD distribution) were found to have decreased DMFS when compared to GAD-high patients (≥25% GAD distribution) (Hazard Ratio (HR) = 2.31 (95% CI 1.25, 4.25), p=0.006). On MVA, GAD was an independent predictor of DMFS for the whole cohort (HR= 2.11 (1.13, 3.94), p=0.02). When the analysis was restricted to the ER positive cohort, GAD was an independent predictor of outcome both as a continuous (HR=0.977, (0.955, 1.0), p = 0.049) and as a dichotomous variable (HR = 3.42, (1.53, 7.67), p=0.003). These results were independently confirmed in the second Karolinska dataset. The 5 year RFS was 95% for GAD-high patients and 76% in GAD-low patients (p=0.027) and GAD was a significant predictor on MVA for RFS (HR =7.42, (1.41, 137.6), p=0.014). In the Karolinska cohort, we estimate a significant proportion of GAD-low patients (59%) would achieve GAD-high with dose escalation up to 70 Gy.

Conclusions: In this study, we develop and validate GAD, a novel and patient-specific measure of radiation dose effect. Importantly, GAD is a clinically actionable metric by adjusting radiation dose. We propose that GAD based radiation dosing is a feasible approach to precision medicine in breast radiation oncology.

Citation Format: Ahmed KA, Scott JG, Diaz RJ, Fulp WJ, Torres-Roca JF. The genomically adjusted radiation dose (GAD) and its association with distant metastases in breast cancer: A feasible approach to precision medicine in radiation oncology. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-12-04.

Clinical outcomes of melanoma brain metastases treated with stereotactic radiation and anti-PD-1 therapy

BACKGROUND

The anti-programmed death-1 (anti-PD-1) therapy nivolumab has significant clinical activity in patients with metastatic melanoma. However, little is known about the safety and outcomes in patients receiving anti-PD-1 therapy and stereotactic radiation for the treatment of brain metastases (BMs).

PATIENTS AND METHODS

Data were analyzed retrospectively from two prospective nivolumab protocols enrolling 160 patients with advanced resected and unresectable melanoma at a single institution. Patients were included if BMs were diagnosed and treated with stereotactic radiation within 6 months of receiving nivolumab. The primary end point of this study was neurotoxicity; secondary end points included BM control and survival.

RESULTS

Twenty-six patients with a total of 73 BMs treated over 30 sessions were identified. Radiation was administered before, during and after nivolumab in 33 lesions (45%), 5 lesions (7%), and 35 lesions (48%), respectively. All BMs were treated with stereotactic radiosurgery (SRS) in a single session except 12 BMs treated with fractionated stereotactic radiation therapy, nine of which were in the postoperative setting. One patient experienced grade 2 headaches following SRS with symptomatic relief with steroid treatment. No other treatment-related neurologic toxicities or scalp reactions were reported. Eight (11%) local BM failures with a ≥20% increase in volume were noted. Of these lesions, hemorrhage was noted in 4, and edema was noted in 7. Kaplan-Meier estimates for local BM control following radiation at 6 and 12 months were 91% and 85%, respectively. Median overall survival (OS) from the date of stereotactic radiation and nivolumab initiation was 11.8 and 12.0 months, respectively, in patients receiving nivolumab for unresected disease (median OS was not reached in patients treated in the resected setting).

CONCLUSIONS

In our series, stereotactic radiation to melanoma BMs is well tolerated in patients who received nivolumab. BM control and OS appear prolonged compared with standard current treatment. Prospective evaluation is warranted.

Differential expression of mannose-6-phosphate receptor regulates T cell contraction

CD8(+) T cells provide protection against pathogens and cancer. After encountering a pathogenic antigen, CD8(+) T cells undergo a triphasic program of rapid proliferation, contraction, and memory formation. Most (∼90-95%) CD8(+) T cells die after vigorous proliferation in the T cell contraction phase, yet the mechanism that triggers apoptotic T cell death remains elusive. This study tested the hypothesis that differential cell-surface expression of M6PR, a multifunctional receptor that regulates lysozyme biogenesis, but also uptakes apoptosis-inducing serine-protease Gzm-B, critically determines life vs. death decisions in T cells. We demonstrate that M6PR-expression on CD8(+) T cell surfaces is dynamically regulated during LmOVA bacterial infection. Notably, time-lapse, confocal microscopy and flow cytometry confirms that M6PR(low) effectors, but not M6PR(high) effectors, escape Gzm-B lethal-hit derived from CD4(+)25(+) Treg cells. Adoptive cotransfer of M6PR(low) effectors and M6PR(high) effectors sorted from LmOVA-infected, congenic mice at the peak of CD8(+) T cell response, reveals that M6PR(low) effectors with the CD8(+) T cell memory precursor phenotype preferentially survive the CD8(+) T cell contraction and differentiate into functional, long-lasting memory CD8(+) T cells. Taken together, our data provide the first evidence, to our knowledge, that selective M6PR down-regulation has a critical role in CD8(+) T cell survival, and our findings have implications for efficient vaccine design and immunotherapy.

Pathology of gastric lesions in donkeys: A preliminary study

REASONS FOR PERFORMING STUDY

Donkeys (Equus africanus asinus) are important working animals, particularly in countries where the majority of the population lives below the poverty line. Gastric ulceration has been shown to be common in British donkeys but donkeys from other parts of the world have not been as extensively researched.

OBJECTIVES

This study was performed as a preliminary overview of the severity and distribution of gastric lesions in mature donkeys and to document which parasites were present.

STUDY DESIGN

Descriptive study of pathological findings.

METHODS

Stomachs of 35 mature draught donkeys were examined grossly and histopathology samples taken from 5 regions of the gastric mucosa.

RESULTS

Gross examination revealed hyperaemia, oedema, erosions and ulcers in addition to parasitic lesions. Histopathological examination revealed hyperkeratosis, acanthosis, vacuolar degeneration of stratified squamous cells, gastritis, erosions, ulcerations, scarring, hyperactivity of mucus glands, periglandular fibroplasia and parasitic granulomes with infestation by Gasterophilus spp. larvae, Habronema spp. and Draschia megastoma.

CONCLUSIONS

In donkeys, ulceration of the nonglandular regions of the stomach is more prominent than the glandular regions and parasitic infestations were frequent.

Cytokines Expression and Nitric Oxide Production under Induced Infection to Salmonella Typhimurium in Chicken Lines Divergently Selected for Cutaneous Hypersensitivity

In the present study, the impact of Salmonella Typhimurium on cell-mediated immunity (CMI) was investigated in 5 week-old immuno divergent broiler lines selected for the high and low response to phytohemagglutinin-P. The immune response was assessed in peripheral-blood mononuclear cells (PBMCs) induced with Salmonella Typhimurium at different time intervals (0 h, 0.5 h, 2 h, 4 h, 6 h, 12 h and 24 h). The differential mRNA expression patterns of IFN-γ, IL-2 and iNOS were evaluated by quantitative real time PCR. In-vitro production of nitric oxide (NO) was also estimated in the culture supernatant and correlated with iNOS mRNA expression. Present study showed higher production of NO in the high cell-mediated line (HCMI) as compared to the low cell-mediated line (LCMI) upon stimulation with Salmonella Typhimurium. Correspondingly, higher mRNA expression of iNOS and IFN-γ were observed in high response birds (HCMI); but IL-2 was down regulated in this line compared to the low response birds (LCMI). Significantly (p<0.05) higher expression of iNOS, IFN-γ and higher production of NO in high line indicated that the selection for PHA-P response might be employed for increasing the immune competence against Salmonella Typhimurium in chicken flocks.

Transgene IL-6 enhances DC-stimulated CTL responses by counteracting CD4+25+Foxp3+ regulatory T cell suppression via IL-6-induced Foxp3 downregulation

Dendritic cells (DCs), the most potent antigen-presenting cells have been extensively applied in clinical trials for evaluation of antitumor immunity. However, the efficacy of DC-mediated cancer vaccines is still limited as they are unable to sufficiently break the immune tolerance. In this study, we constructed a recombinant adenoviral vector (AdVIL-6) expressing IL-6, and generated IL-6 transgene-engineered DC vaccine (DCOVA/IL-6) by transfection of murine bone marrow-derived ovalbumin (OVA)-pulsed DCs (DCOVA) with AdVIL-6. We then assessed DCOVA/IL-6-stimulated cytotoxic T-lymphocyte (CTL) responses and antitumor immunity in OVA-specific animal tumor model. We demonstrate that DCOVA/IL-6 vaccine up-regulates expression of DC maturation markers, secretes transgene-encoded IL-6, and more efficiently stimulates OVA-specific CTL responses and therapeutic immunity against OVA-expressing B16 melanoma BL6-10OVA in vivo than the control DCOVA/Null vaccine. Moreover, DCOVA/IL-6-stimulated CTL responses were relatively maintained in mice with transfer of CD4+25+Foxp3+ Tr-cells, but significantly reduced when treated with anti-IL-6 antibody. In addition, we demonstrate that IL-6 down-regulates Foxp3-expression of CD4+25+Foxp3+ Tr-cells in vitro. Taken together, our results demonstrate that AdV-mediated IL-6 transgene-engineered DC vaccine stimulates potent CTL responses and antitumor immunity by counteracting CD4+25+ Tr immunosuppression via IL-6-induced Foxp3 down-regulation. Thus, IL-6 may be a good candidate for engineering DCs for cancer immunotherapy.

In vitro rapid clearance of infectious bursal disease virus in peripheral blood mononuclear cells of chicken lines divergent for antibody response might be related to the enhanced expression of proinflammatory cytokines

Infectious bursal disease (IBD) is an acute and highly contagious viral disease of young chickens caused by infectious bursal disease virus (IBDV). An effective way to control IBDV would be to breed chickens with a reduced susceptibility to IBDV infection. In the present work, we used chickens selected for high and low specific responses to sheep red blood cells (SRBC) (H and L, respectively) to assess the susceptibility of differential immune competent animals to IBDV infection. The peripheral blood mononuclear cells (PBMCs) of high SRBC line (HL) and low SRBC line (LL) were infected with IBDV and viral RNA loads were determined at different time post-IBDV infection. Chicken orthologues of the T helper 1 (Th1) cytokines, interferon-γ (IFN-γ) and interleukin-2 (IL-2); a Th2 cytokine, IL-10; a pro inflammatory cytokine, IL-6; the CCL chemokines, chCCLi2, chCCLi4 and chCCLi7; colony stimulating factor, GM-CSF; and a anti-inflammatory cytokine, transforming growth factor β-2 (TGFβ-2) were quantified. The expression of chCCLi2, chCCLi4 and chCCLi7 was significantly higher in L line as compared to H line. However, in H line the viral RNA loads were significantly lower than in L line. Therefore, the upregulated chemokines might be associated with the susceptibility to IBDV. The expression of IFN-γ, IL-2 and IL-6 was significantly higher in H line as compared to L line. We assume that the higher proinflammatory cytokines expression in H line might be related to the rapid clearance of virus from PBMCs. Significantly higher levels of IL-10 and TGFβ-2 mRNAs in L line might be related to the pathogenesis of IBDV. In conclusion, selection for antibody responses appears to influence the expression profiles of chemokines and cytokines against IBDV. Further, the selection for high SRBC response might improve the immuno-competence of chickens against IBDV.

Direct in vivo evidence of CD4+ T cell requirement for CTL response and memory via pMHC-I targeting and CD40L signaling

CD4(+) T cell help contributes critically to DC-induced CD8(+) CTL immunity. However, precisely how these three cell populations interact and how CD4(+) T cell signals are delivered to CD8(+) T cells in vivo have been unclear. In this study, we developed a novel, two-step approach, wherein CD4(+) T cells and antigen-presenting DCs productively engaged one another in vivo in the absence of cognate CD8(+) T cells, after which, we selectively depleted the previously engaged CD4(+) T cells or DCs before allowing interactions of either population alone with naïve CD8(+) T cells. This protocol thus allows us to clearly document the importance of CD4(+) T-licensed DCs and DC-primed CD4(+) T cells in CTL immunity. Here, we provide direct in vivo evidence that primed CD4(+) T cells or licensed DCs can stimulate CTL response and memory, independent of DC-CD4(+) T cell clusters. Our results suggest that primed CD4(+) T cells with acquired pMHC-I from DCs represent crucial "immune intermediates" for rapid induction of CTL responses and for functional memory via CD40L signaling. Importantly, intravital, two-photon microscopy elegantly provide unequivocal in vivo evidence for direct CD4-CD8(+) T cell interactions via pMHC-I engagement. This study corroborates the coexistence of direct and indirect mechanisms of T cell help for a CTL response in noninflammatory situations. These data suggest a new "dynamic model of three-cell interactions" for CTL immunity derived from stimulation by dissociated, licensed DCs, primed CD4(+) T cells, and DC-CD4(+) T cell clusters and may have significant implications for autoimmunity and vaccine design.

Mechanisms of cellular communication through intercellular protein transfer

In a multicellular system, cellular communication is a must for orchestration and coordination of cellular events. Advent of the latest analytical and imaging tools has allowed us to enhance our understanding of the intercellular communication. An intercellular exchange of proteins or intact membrane patches is a ubiquitous phenomenon, and has been the subject of renewed interest, particularly in the context of immune cells. Recent evidence implicates that intercellular protein transfers, including trogocytosis is an important mechanism of the immune system to modulate immune responses and transferred proteins can also contribute to pathology. It has been demonstrated that intercellular protein transfer can be through the internalization/pathway, dissociation-associated pathway, uptake of exosomes and membrane nanotube formations. Exchange of membrane molecules/antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. In this review, we will discuss the important findings concerning intercellular protein transfers, possible mechanisms and highlight their physiological relevance to the immune system, with special reference to T cells such as the stimulatory or suppressive immune responses derived from T cells with acquired dendritic cell membrane molecules.

Active CD4+ helper T cells directly stimulate CD8+ cytotoxic T lymphocyte responses in wild-type and MHC II gene knockout C57BL/6 mice and transgenic RIP-mOVA mice expressing islet beta-cell ovalbumin antigen leading to diabetes

CD4+ helper T (Th) cells play crucial role in priming, expansion and survival of CD8+ cytotoxic T lymphocytes (CTLs). However, how CD4+ Th cell's help is delivered to CD8+ T cells in vivo is still unclear. We previously demonstrated that CD4+ Th cells can acquire ovalbumin (OVA) peptide/major histocompatibility complex (pMHC I) and costimulatory CD80 by OVA-pulsed DC (DC(OVA)) stimulation, and then stimulate OVA-specific CD8+ CTL responses in C57BL/6 mice. In this study, we further investigated CD4+ Th cell's effect on stimulation of CD8 CTL responses in major histocompatibility complex (MHC II) gene knockout (KO) mice and transgenic rat insulin promoter (RIP)-mOVA mice with moderate expression of self OVA by using CD4+ Th cells or Th cells with various gene deficiency. We demonstrated that the in vitro DC(OVA)-activated CD4+ Th cells (3 x 10(6) cells/mouse) can directly stimulate OVA-specific CD8+ T-cell responses in wild-type C57BL/6 mice and MHC II gene KO mice lacking CD4+ T cells. A large amount of CD4+ Th cells (12 x 10(6) cells/mouse) can even overcome OVA-specific immune tolerance in transgenic RIP-mOVA mice, leading to CD8+ CTL-mediated mouse pancreatic islet destruction and diabetes. The stimulatory effect of CD4+ Th cells is mediated by its IL-2 secretion and CD40L and CD80 costimulations, and is specifically delivered to OVA-specific CD8+ T cells in vivo via its acquired pMHC I complexes. Therefore, the above elucidated principles for CD4+ Th cells will have substantial implications in autoimmunity and antitumor immunity, and regulatory T-cell-dependent immune suppression.

Cytokines and chemokines in postovulatory follicle regression of domestic chicken (Gallus gallus domesticus)

The mechanism of postovulatory follicle (POF) regression in birds is still poorly understood. In the current study, expression of IL-1beta, IL-6, GM-CSF, IFN-gamma, IL-2, IL-4, IL-13, chCXCLi2, chCCLi2, chCCLi4, chCCLi7, IL-10 and TGF-beta2 mRNAs was estimated in regressing POF by semi-quantitative RT-PCR. In addition, the changes in immune cell population, histological and apoptotic changes were also studied in regressing POF. The expression of cytokines (IL-1beta, IL-6, IL-10 and TGF-beta2) and chemokines (chCXCLi2, chCCLi2, chCCLi4 and chCCLi7) was upregulated in POFs, suggesting a role for these molecules in tissue regression. The histological findings suggested a significant infiltration of immune cells, especially heterophils, lymphocytes and macrophages, into the regressing POF. The flow cytometry analysis of lymphocyte subpopulations revealed that CD3(+), CD4(+), CD8(+) and Bu-1(+) lymphocytes were significantly increased during this regression. The significant up-regulation of chemokines might have attracted the immune cells during POF regression. The percentage of apoptotic cells was significantly increased during the regression of POF. The up-regulation of IL-1beta, IL-6, IL-10 and TGF-beta2 and down-regulation of GM-CSF might have induced apoptosis during the POF regression. However, expression of IFN-gamma, IL-2, IL-4 and IL-13 was not significantly altered during POF regression. In conclusion, cytokines appear to play an important role in the regression of POF in chicken. Furthermore, the regression of chicken POF seems to be an inflammatory event similar to luteolysis of the mammalian corpus luteum.

Spatial expression of chemokines and cytokines mRNA in the largest preovulatory follicle of chicken

In the present experiment, we studied the spatial expression profiles of chemokines and cytokines mRNA in the granulosa (F1Gr) and theca (F1Th) layers of the largest preovulatory follicle in chicken using semi-quantitative PCR. The mRNAs of IL-1beta, IL-6, GM-CSF, chCXCLi2, chCCLi2, chCCLi4, chCCLi7, IFN-gamma, IL-4, IL-13, IL-10 and TGF-beta2 were expressed in the granulosa (F1Gr) and theca (F1Th) layers of the largest preovulatory follicle. However, the transcripts of IL-2 were not detected in any of the samples tested. Significantly higher levels of IL-6 and GM-CSF mRNA expression were noticed in F1Gr when compared to F1Th layer. Expression of chCXCLi2, a CXC chemokine, was almost similar in F1Gr and F1Th layers. However, the expression of CCL chemokines i.e. chCCLi2, chCCLi4, chCCLi7 mRNAs were almost 2 folds higher in F1Th layer in comparison to F1Gr layer. The expression of Th2 cytokines (IL-4 and IL-13) mRNA was noticed in F1Gr and F1Th layers with higher levels in the former. Expression of IFN-gamma mRNA was noticed in F1Gr and F1Th layers. Significantly higher level of TGF-beta2 expression was observed in F1Th in comparison to F1Gr layer. It was concluded from the present study that the mRNA expression of cytokines and chemokines are differentially regulated in the granulosa and theca layers of the largest preovulatory follicle in chicken.

Nitric oxide: A possible mediator of ovulation and postovulatory follicle regression in chicken

Nitric oxide (NO) has recently emerged as a regulator of functional and structural regression in mammalian reproductive tissues. However, the role of NO in ovulation and postovulatory follicles (POF) that undergo regression in laying birds is unclear. In the present investigation, the expression profiles of iNOS mRNA, tissue NO levels and the percentage of apoptotic cells were studied in the regressing chicken postovulatory follicle (POF). The postovulatory follicles gradually lost weight during its regression and reached the lowest weight on POF5. The number of apoptotic cells was increased significantly during the regression of POF. The mRNA expression of iNOS was noticed in the second largest preovulatory follicle (F2) that subsequently increased in the largest preovulatory follicle (F1). However, the level of iNOS mRNA was declined immediately after ovulation and thereafter upregulated again to reach a peak in POF3 with a subsequent reduction in POF5 to below the basal level. The tissue NO levels followed a similar pattern except with a peak production in POF4. The gross regression and apoptosis in POFs were well associated with iNOS expression and NO production. In conclusion, NO appears to play a role in ovulation and regression of postovulatory follicle in chicken.

Effects of supplemental chromium on interferon-gamma (IFN-gamma) mRNA expression in response to Newcastle disease vaccine in broiler chicken

We report the effects of supplemental chromium (Cr) on interferon-gamma (IFN-gamma) expression in response to Newcastle disease virus (NDV) vaccine in broiler chicken. Two hundred and eighty day old straight run broiler chicks were randomly selected and allocated at random to one of the seven treatment groups replicated four times having 10 chicks in each replication. Treatment 1 (C) was a standard control diet in which no Cr was offered to birds either through feed or drinking water. In treatments 2-4 (F500, F1000 and F1500), Cr in the form of chromium picolinate (CrPic) was added at rates of 500, 1000 and 1500 ppb in diets, respectively. In treatments 5-7 (W250, W500 and W750), Cr as added to the drinking water at rates of 250, 500 and 750 ppb, respectively. The feeding was continued from 1 to 49 d of age. On 49 d, three birds from each replicate, i.e. 12 birds/treatment were inoculated intramuscularly with R(2)B strain of NDV. Twelve unvaccinated birds along with 12 vaccinated birds from each treatment (four birds each day) were then sacrificed on 1, 3 and 7 days post-immunization to study the IFN-gamma expression using quantitative real time PCR. Following the immunization, the IFN-gamma mRNA expression in spleen was significantly (P<0.01) either up-regulated or down-regulated at day 1 and day 3 post-stimulation. Whereas, IFN-gamma mRNA expression reached basal level in all the vaccinated groups at day 7 post-stimulation. IFN-gamma mRNA expression on day 1 was approximately two and four times higher than the control (C) levels in F500 and W500 groups, respectively. On 3 day post-immunization, IFN-gamma mRNA expression in spleen was about 40 and 27 times higher than controls (C) in F500 and W500 groups, respectively. Other groups (F1000, F1500, W250 and W750) showed down-regulation of IFN-gamma mRNA expression. The results suggested that the dosage of chromium modulates the expression of IFN-gamma and route has effect on the onset and duration of the response. Thus, the supplementation of chromium at appropriate dose might be helpful to enhance the IFN-gamma mRNA expression in response to NDV.

Caspase-mediated apoptosis in chicken postovulatory follicle regression

Chicken postovulatory follicle (POF) regression occurs via the process of apoptosis. However, the signals and initiator pathways responsible for regression of the POF are unknown. In the current study, we examined gene expression patterns of various caspases (caspase-1, -2 and -3) involved in apoptosis by semi-quantitative RT-PCR. The percentage of apoptotic cells during POF regression was also quantified by flow cytometry. Expression of caspase-3 mRNA was noted in the largest preovulatory follicle (F1). However, the initiator caspases (caspase-1 and -2) were not expressed in F1. During the regression of the POF, caspase-3 was activated during initial stages, whereas the initiator caspases were upregulated at the later stages (POF4 and POF5). The percentage of apoptotic cells was significantly higher during the regression of the POF. It might be possible that levels of caspase-3 mRNA do not necessarily reflect the cell's potential for facilitating apoptosis, as activation of the caspase-3 by initiator caspases is required for its function. We presume that both caspase-1 and caspase-2 were key initiators in the regression of chicken POF and that the apoptosis-mediated regression of POFs might be similar to mammalian corpus luteum involution.

Molecular cloning and sequencing of MHC class II beta 1 domain of turkey reveals high sequence identity with chicken

We report the nucleotide sequences of turkey (Meleagris gallopavo) major histocompatibility complex (MHC) class II loci (beta 1 domain or exon 2 encoding the peptide-binding region). In the present investigation, three distinct sequences from the beta 1 domain of turkey MHC class II were isolated. A BLAST search and phylogenetic analysis revealed that turkey MHC sequences are most similar to chicken and peacock MHC. There was no strong evidence of recombination among the turkey MHC sequences or with other avian MHC, but diversity was high. The diversity in this peptide-binding region may be the result of point mutation and balancing selection or frequent gene conversion within turkey. However, more work and data are needed to understand the evolution of turkey and other avian MHC. Moreover, polymerase chain reaction-restriction fragment-length polymorphism analysis of exon 2 using the Hinf I restriction enzyme demonstrated three restriction patterns and a preliminary evidence of multiple beta loci in turkey. PCR-RFLP analysis of turkey MHC class II loci could be a promising method of MHC genotyping, when more sequences are available. Turkey MHC haplotypes identified earlier by RFLP analysis should be sequenced to standardize turkey MHC nomenclature and to develop DNA based method of haplotyping.

Cytokines in reproductive remodeling of molting White Leghorn hens

The role of cytokines in regression of the ovary and oviduct during induced molting in chickens was investigated by evaluating the expressions of IL-1beta, IL-6, IFN-gamma, IL-2, TGF-beta2, MIP-1beta and IL-8 in the regressing ovary and oviduct by semi-quantitative RT-PCR. In addition, serum hormonal profiles (estrogen, progesterone and corticosterone), along with the gross regression and histological changes of the ovary and oviduct, were investigated. The correlation between expression of cytokines and hormonal changes during the induced molting was also studied. The expression of IL-6, IL-8, MIP-1beta and IFN-gamma mRNAs in the ovary, and IL-1beta, IL-6, IL-8, MIP-1beta, IFN-gamma and TGF-beta2 mRNAs in the oviduct, were up-regulated significantly during induced molting, suggesting their role in tissue regression. However, histological findings suggested no significant increase in immune cells in the regressing oviduct and ovary. Significant up-regulation of TGF-beta2 in the regressing oviduct might have suppressed leukocyte recruitment thereby preventing the inflammatory response and tissue damage. The down-regulation of estrogen and progesterone and up-regulation of corticosterone is well correlated with increased expression of cytokines. It appears that cytokines released during the process of induced molting may have a role in decreasing ovarian steroids and increasing the corticosterone levels in chicken. From this study, it may be concluded that cytokines play a major role in regression of the ovary and oviduct during induced molting in chickens.

Temporal expression of transforming growth factor-beta2 and myostatin mRNA during embryonic myogenesis in Indian broilers

TGF-beta2 and myostatin, the members of TGF family, act through both autocrine and paracrine mechanisms to regulate the growth and differentiation at various developmental stages in chicken. The kinetics and expression profile of these two growth factors were investigated by semi-quantitative RT-PCR, during the myogenesis of Indian broiler chickens. Total RNA was isolated from whole embryos on each of embryonic days (E) 0-6 (n=3 per day) and from the biceps femoris muscle at E7-E18 (n=3 per day). The expression of TGF-beta2 was noticed on E2 that remained at the same level until E6. In biceps femoris muscle, higher level of TGF-beta2 expression was observed during E7-E12, which decreased gradually thereafter. These findings suggested that TGF-beta2 might be a regulatory factor participating in the myogenesis of chicken embryos. Initial myostatin expression was noticed on E1, even before the myogenic lineage is established in embryo. This finding suggested an additional role of myostatin in early chicken embryo development, other than myogenesis. Furthermore, myostatin expression was significantly higher on E3 as compared to earlier studies, where initial higher level was observed at E2, suggesting the differential expression of myostatin among breeds. Higher and almost static myostatin expression was noticed in biceps femoris muscle during the entire period of myogenesis (E7-E18). In the present study, the ontogeny of myostatin expression coincided with myogenesis of chicken. Therefore, it may be hypothesized that myostatin is not only a major determinant of muscle mass, but also involved in early embryogenesis in chickens.

Differential expression of inducible nitric oxide synthase and cytokine mRNA in chicken lines divergent for cutaneous hypersensitivity response

Phytohemagglutinin (PHA)-induced delayed-type hypersensitivity is an immunocompetent trait considered an indicator of cell-mediated immune or T-cell responses. Divergent selection was performed to generate high and low lines for response to PHA-P. Extreme-responder birds of the F2 generation in each line were used to study possible differences in macrophage activity and the associated functional genes. To evaluate macrophage activity, nitric oxide (NO) was estimated both systemically in serum and in in vitro monocyte culture. Semi-quantitative RT-PCR was used to detect the differential mRNA expression patterns of iNOS and MIP-1beta in monocyte culture, whereas T(H)1 cytokines (IL-2 and IFN-gamma) were studied in peripheral blood mononuclear cells (PBMC) at different time intervals after lipopolysaccharide (LPS) induction. The high line showed strong systemic, as well as in vitro NO production, compared to the low line, upon stimulation with NDV and LPS, similar to early and high iNOS mRNA expression. Following the pattern of iNOS gene expression, an early strong expression of cytokines with powerful iNOS-inducing action, such as IFN-gamma and the chemokine MIP-1beta, was observed in the high line. In contrast, for response to PHA-P, low expression of IL-2 was observed in the high compared to the low line. In conclusion, the study revealed that divergent selection for response to PHA-P resulted in a divergent effect on T(H)1 cell activity, resulting in altered macrophage function in chickens. Selection, based on response to PHA-P, could lead to more resistant birds or birds with an enhanced immune response.

Synthesis and antimicrobial activities of novel naphtho[2,1-b]pyran, pyrano[2,3-d]pyrimidine and pyrano[3,2-e][1,2,4]triazolo[2,3-c]-pyrimidine derivatives

The synthesis of new naphtho[1',2':5,6]pyrano[2,3-d]pyrimidines and related heterocycles has been reported. The key intermediate 3-amino-8-bromo-1-(p-methoxyphenyl)-1H-naphtho[2,1-b] pyran-2-carbonitrile (3c) was obtained in one pot synthesis by treating alpha-cyanocinnamonitrile (1c) with 6-bromo-2-naphthol (2). Antimicrobial activity was shown for some of the synthesized compounds.

The influence of plasma glucose upon pulsatile ocular blood flow in subjects with type II diabetes mellitus

AIMS/HYPOTHESIS

This study investigated the influence of plasma glucose upon pulsatile ocular blood flow in subjects with Type II (non-insulin-dependent) diabetes mellitus.

METHODS

A total of 19 subjects with Type II diabetes and 8 normal control subjects undertook a meal tolerance test after an overnight fast. The pulsatile ocular blood flow, using the Ocular Blood Flow Tonometer, and plasma glucose concentrations were taken at times 0 min, 90 min and 240 min. Blood pressure and glycated haemoglobin concentrations, in the subjects with diabetes, were also measured at time 0 min. Pulsatile ocular blood flow and plasma glucose were also measured at times 0 and 90 min in 5 subjects with Type II diabetes mellitus who remained fasting.

RESULTS

It was found that the subjects with diabetes who undertook the meal tolerance test showed a significant increase in both plasma glucose concentrations and pulsatile ocular blood flow from time 0-90 min, followed by a decrease from 90 min to the end of the session at 240 min. (p < 0.001 in each case). Regression analysis showed a significant correlation between the change in pulsatile ocular blood flow and the change in plasma glucose concentration (r = 0.671,p = 0.001). Control subjects showed no significant change in either plasma glucose or pulsatile ocular blood flow during the meal tolerance test. Subjects with diabetes mellitus who remained fasting also showed no significant change in pulsatile ocular blood flow or plasma glucose concentrations. No correlation was found between glycated haemoglobin concentrations or blood pressure and pulsatile ocular blood flow.

CONCLUSION/INTERPRETATION

Pulsatile ocular blood flow is influenced by changes in plasma glucose concentrations in Type II diabetes mellitus, indicating that uncontrolled hyperglycaemia might result in a higher pulsatile ocular blood flow than might otherwise be expected.

Efficacy of concomitant chemoradiation and surgical salvage for N3 nodal disease associated with upper aerodigestive tract carcinoma

OBJECTIVES/HYPOTHESIS

To determine whether an aggressive approach using trimodality therapy would improve the outcome in head and neck cancer patients with advanced (N3) nodal disease.

STUDY DESIGN

In this retrospective, nonrandomized review, we analyzed a subset of patients who were treated in a targeted chemoradiation therapy protocol, consisting of 31 patients who received treatment between June 1993 and June 1997.

METHODS

Patients received selective intra-arterial infusions of cisplatin (150 mg/m2/wk for 4 weeks) and concomitant radiation therapy (2 Gy/fraction x 35 daily fractions over a 7-wk period) to the primary and clinically positive nodal disease. The patients were re-evaluated 2 months later and underwent salvage neck dissections if there was any residual disease.

RESULTS

Classification of disease in the primary site was as follows: T1 in 2 patients, T2 in 6 patients, T3 in 14 patients, and T4 in 9 patients. Among the 31 patients who were assessed for response at the nodal site, 4 of 31 (13%) had a complete response, 21 of 31 (68%) had a partial response, and 1 of 31 (3%) had no response. Excluding the 5 patients who could not be evaluated, 4 of 26 patients (15%) had a complete response, 21 of 26 (81%) had a partial response, and 1 of 26 (4%) had no response. Nineteen patients subsequently underwent neck dissection, and five patients had histological evidence of residual disease. The remaining seven patients included four who had a complete response in their necks and three who died of intercurrent disease before re-staging. Among the 23 patients who were rendered disease free, there were no recurrences within the neck, whereas 1 patient had recurrence at the primary site and 11 patients had recurrence at distant sites. With a median follow-up of 15 months (range, 4-41 mo), the 3-year overall survival and disease-specific survival were 41% and 43%, respectively.

CONCLUSIONS

Targeted chemoradiation therapy followed by surgical salvage is a highly effective approach for regional control of patients with N3 nodal disease, whereas additional strategies are required to address the problem of distant metastases.