Assay Harmonization Study To Measure Immune Response to SARS-CoV-2 Infection and Vaccines: a Serology Methods Study

The Coronavirus disease 2019 (COVID-19) pandemic presented the scientific community with an immediate need for accurate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology assays, resulting in an expansion of assay development, some without following a rigorous quality control and validation, and with a wide range of performance characteristics. Vast amounts of data have been gathered on SARS-CoV-2 antibody response; however, performance and ability to compare the results have been challenging. This study seeks to analyze the reliability, sensitivity, specificity, and reproducibility of a set of widely used commercial, in-house, and neutralization serology assays, as well as provide evidence for the feasibility of using the World Health Organization (WHO) International Standard (IS) as a harmonization tool. This study also seeks to demonstrate that binding immunoassays may serve as a practical alternative for the serological study of large sample sets in lieu of expensive, complex, and less reproducible neutralization assays. In this study, commercial assays demonstrated the highest specificity, while in-house assays excelled in antibody sensitivity. As expected, neutralization assays demonstrated high levels of variability but overall good correlations with binding immunoassays, suggesting that binding may be reasonably accurate as well as practical for the study of SARS-CoV-2 serology. All three assay types performed well after WHO IS standardization. The results of this study demonstrate there are high performing serology assays available to the scientific community to rigorously dissect antibody responses to infection and vaccination. IMPORTANCE Previous studies have shown significant variability in SARS-CoV-2 antibody serology assays, highlighting the need for evaluation and comparison of these assays using the same set of samples covering a wide range of antibody responses induced by infection or vaccination. This study demonstrated that there are high performing assays that can be used reliably to evaluate immune responses to SARS-CoV-2 in the context of infection and vaccination. This study also demonstrated the feasibility of harmonizing these assays against the International Standard and provided evidence that the binding immunoassays may have high enough correlation with the neutralization assays to serve as a practical proxy. These results represent an important step in standardizing and harmonizing the many different serological assays used to evaluate COVID-19 immune responses in the population.

SARS-CoV-2 IgG Spike antibody levels and avidity in natural infection or following vaccination with mRNA-1273 or BNT162b2 vaccines

Certain aspects of the immunogenicity and effectiveness of the messenger ribonucleic acid (mRNA) vaccines (mRNA-1273 and BNT162b2) developed in response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic are still uncharacterized. Serum or plasma samples from healthy donor recipients of either vaccine (BNT162b2 n = 53, mRNA-1273 n = 49; age 23-67), and individuals naturally infected with SARS-CoV-2 (n = 106; age 18-82) were collected 0-2 months post-infection or 1- and 4 months after second dose of vaccination. Anti-Spike antibody levels and avidity were measured via an enzyme-linked immunosorbent assay (ELISA). Overall, vaccination induced higher circulating anti-Spike protein immunoglobulin G (IgG) antibody levels and avidity compared to infection at similar time intervals. Both vaccines produced similar anti-Spike IgG concentrations at 1 month, while mRNA-1273 demonstrated significantly higher circulating antibody concentrations after 4 months. mRNA-1273 induced significantly higher avidity at month 1 compared to BNT162b2 across all age groups. However, the 23-34 age group was the only group to maintain statistical significance by 4 months. Male BNT162b2 recipients were approaching statistically significant lower anti-Spike IgG avidity compared to females by month 4. These findings demonstrate enhanced anti-Spike IgG levels and avidity following vaccination compared to natural infection. In addition, the mRNA-1273 vaccine induced higher antibody levels by 4 months compared to BNT162b2.

A Trans-Governmental Collaboration to Independently Evaluate SARS-CoV-2 Serology Assays

The emergence of SARS-CoV-2 created a crucial need for serology assays to detect anti-SARS-CoV-2 antibodies, which led to many serology assays entering the market. A trans-government collaboration was created in April 2020 to independently evaluate the performance of commercial SARS-CoV-2 serology assays and help inform U.S. Food and Drug Administration (FDA) regulatory decisions. To assess assay performance, three evaluation panels with similar antibody titer distributions were assembled. Each panel consisted of 110 samples with positive (n = 30) serum samples with a wide range of anti-SARS-CoV-2 antibody titers and negative (n = 80) plasma and/or serum samples that were collected before the start of the COVID-19 pandemic. Each sample was characterized for anti-SARS-CoV-2 antibodies against the spike protein using enzyme-linked immunosorbent assays (ELISA). Samples were selected for the panel when there was agreement on seropositivity by laboratories at National Cancer Institute's Frederick National Laboratory for Cancer Research (NCI-FNLCR) and Centers for Disease Control and Prevention (CDC). The sensitivity and specificity of each assay were assessed to determine Emergency Use Authorization (EUA) suitability. As of January 8, 2021, results from 91 evaluations were made publicly available (https://open.fda.gov/apis/device/covid19serology/, and https://www.cdc.gov/coronavirus/2019-ncov/covid-data/serology-surveillance/serology-test-evaluation.html). Sensitivity ranged from 27% to 100% for IgG (n = 81), from 10% to 100% for IgM (n = 74), and from 73% to 100% for total or pan-immunoglobulins (n = 5). The combined specificity ranged from 58% to 100% (n = 91). Approximately one-third (n = 27) of the assays evaluated are now authorized by FDA for emergency use. This collaboration established a framework for assay performance evaluation that could be used for future outbreaks and could serve as a model for other technologies. IMPORTANCE The SARS-CoV-2 pandemic created a crucial need for accurate serology assays to evaluate seroprevalence and antiviral immune responses. The initial flood of serology assays entering the market with inadequate performance emphasized the need for independent evaluation of commercial SARS-CoV-2 antibody assays using performance evaluation panels to determine suitability for use under EUA. Through a government-wide collaborative network, 91 commercial SARS-CoV-2 serology assay evaluations were performed. Three evaluation panels with similar overall antibody titer distributions were assembled to evaluate performance. Nearly one-third of the assays evaluated met acceptable performance recommendations, and two assays had EUAs revoked and were removed from the U.S. market based on inadequate performance. Data for all serology assays evaluated are available at the FDA and CDC websites (https://open.fda.gov/apis/device/covid19serology/, and https://www.cdc.gov/coronavirus/2019-ncov/covid-data/serology-surveillance/serology-test-evaluation.html).

TIPICO XI: report of the first series and podcast on infectious diseases and vaccines (aTIPICO)

TIPiCO is an annual expert meeting and workshop on infectious diseases and vaccination. The edition of 2020 changed its name and format to aTIPiCO, the first series and podcasts on infectious diseases and vaccines. A total of 13 prestigious experts from different countries participated in this edition launched on the 26 November 2020. The state of the art of coronavirus disease-2019 (COVID-19) and the responsible pathogen, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and the options to tackle the pandemic situation were discussed in light of the knowledge in November 2020. Despite COVID-19, the status of other infectious diseases, including influenza infections, respiratory syncytial virus disease, human papillomavirus infection, measles, pertussis, tuberculosis, meningococcal disease, and pneumococcal disease, were also addressed. The essential lessons that can be learned from these diseases and their vaccines to use in the COVID-19 pandemic were also commented with the experts.

Antibodies to SARS-CoV-2 in All of Us Research Program Participants, January 2-March 18, 2020

Background

With limited severe acute respiratory syndrome coronavirus (SARS-CoV-2) testing capacity in the United States at the start of the epidemic (January–March 2020), testing was focused on symptomatic patients with a travel history throughout February, obscuring the picture of SARS-CoV-2 seeding and community transmission. We sought to identify individuals with SARS-CoV-2 antibodies in the early weeks of the US epidemic.

Methods

All of Us study participants in all 50 US states provided blood specimens during study visits from 2 January to 18 March 2020. Participants were considered seropositive if they tested positive for SARS-CoV-2 immunoglobulin G (IgG) antibodies with the Abbott Architect SARS-CoV-2 IgG enzyme-linked immunosorbent assay (ELISA) and the EUROIMMUN SARS-CoV-2 ELISA in a sequential testing algorithm. The sensitivity and specificity of these ELISAs and the net sensitivity and specificity of the sequential testing algorithm were estimated, along with 95% confidence intervals (CIs).

Results

The estimated sensitivities of the Abbott and EUROIMMUN assays were 100% (107 of 107 [95% CI: 96.6%–100%]) and 90.7% (97 of 107 [83.5%–95.4%]), respectively, and the estimated specificities were 99.5% (995 of 1000 [98.8%–99.8%]) and 99.7% (997 of 1000 [99.1%–99.9%]), respectively. The net sensitivity and specificity of our sequential testing algorithm were 90.7% (97 of 107 [95% CI: 83.5%–95.4%]) and 100.0% (1000 of 1000 [99.6%–100%]), respectively. Of the 24 079 study participants with blood specimens from 2 January to 18 March 2020, 9 were seropositive, 7 before the first confirmed case in the states of Illinois, Massachusetts, Wisconsin, Pennsylvania, and Mississippi.

Conclusions

Our findings identified SARS-CoV-2 infections weeks before the first recognized cases in 5 US states.

The influence of exercise intensity and exercise mode on gastrointestinal damage

Strenuous exercise increases gastrointestinal damage, but the dose-response relationship is yet to be elucidated. It is also commonly believed that running causes greater gastrointestinal damage than cycling. Two randomised, crossover studies aimed to 1) quantify gastrointestinal damage with increasing exercise intensity, and 2) determine if running was associated with greater gastrointestinal damage than cycling. Following a maximal oxygen uptake (V̇O_2max) test, participants completed 3 cycling trials at different intensities (60 min at 40%, 60% and 80% V̇O_2max; n = 10 (5 female, 5 male)) (INTENSITY), or 1 running and 1 cycling trial (45 min at 70% V̇O_2max; n = 11 (3 female, 8 male)) (MODE). Venous blood samples were collected pre- and post-exercise to measure gastrointestinal damage via intestinal fatty acid binding protein (I-FABP). In INTENSITY, I-FABP magnitude of change was greater at 80% V̇O_2max than 40% V̇O_2max (p < 0.01). In MODE, I-FABP magnitude of change was greater with cycling (mean (SD)) (84.7 (133.2)% d = 1.07) compared with running (19.3 (33.1)%, d = 0.65) with a moderate effect (d = 0.68, p = 0.024). Rating of perceived exertion (RPE) and heart rate (HR) were higher during cycling (RPE p < 0.0001; HR p < 0.0001) but rectal temperature was not different between modes (p = 0.94). While gastrointestinal damage increases with increasing exercise intensity, running was not associated with greater gastrointestinal damage than cycling. Novelty: A fraction of the anaerobic threshold, rather than a fraction of V̇O_2max, may be more predictive of intensity that results in exercise induced gastrointestinal damage. The mode of exercise may not be as important as intensity for inducing gastrointestinal damage. Improving anaerobic threshold may reduce susceptibility to gastrointestinal damage when exercising at high intensities.

LB-15. A Trans-Governmental Collaborative Effort to Independently Evaluate SARS-CoV-2 Serology Assays Using Well-Characterized Sample Panels

Background

The emergence of the novel coronavirus, SARS-CoV-2, created a crucial need for accurate tests for diagnosis, assessment of prior infection, and understanding its natural history. Serology assays play an important role in the assessment of anti-viral immune responses and previous infections. Evaluation of serology assays with well-characterized serum and/or plasma samples is critical to determine assay performance. CDC, FDA and NCI’s Frederick National Laboratory for Cancer Research (NCI-FNLCR) have established a collaborative network to independently evaluate commercial antibody tests prior to their authorization.

Methods

Positive (n=30) serum samples with a range of anti-SARS-CoV-2 antibody titers (Table) and negative (n=80) serum and/or plasma samples were selected to establish performance evaluation panels (PEVs). Three PEVs with similar overall antibody titer distribution have been created. Negative samples were collected prior to 2020, before the SARS-CoV-2 pandemic. Positive samples were from patients previously confirmed to have SARS-CoV-2 using a nucleic acid amplification test. Each sample was characterized at CDC and NCI-FNLCR for presence/absence of SARS-CoV-2 IgM and IgG antibodies using a SARS-CoV-2 spike enzyme linked immunosorbent assay (ELISA). NCI-FNLCR also performed a SARS-CoV-2 spike Receptor Binding Domain (RBD) IgG ELISA. Positive samples were assessed at multiple dilutions. Manufacturers submitted their serology assays for evaluation by this program. The sensitivity of each test was assessed for each antibody class (IgG and IgM) and in a combined manner, where a positive result for either antibody was considered as a positive result. For combined specificity, a negative result meant a sample was negative for both antibodies (IgG and IgM).

Number of positive samples with anti-SARS-CoV-2 spike antibodies for each panel (n=30)

Results

To date, 53 serology assays have been evaluated. Sensitivity ranged from 30.0% to 100% for IgG, from 10.0% to 100% for IgM, and the combined specificity ranged from 57.5% to 100%. For 2 assays that measure total Ig, sensitivity was 96.7% and 100%.

Conclusion

This program completed over 50 performance evaluations with well-characterized PEVs. Results have been used to inform FDA regulatory decisions and are publicly available on FDA’s website.

Disclosures

Cristina Cassetti, PhD, Nothing to disclose

HEx: A heterologous expression platform for the discovery of fungal natural products

For decades, fungi have been a source of U.S. Food and Drug Administration-approved natural products such as penicillin, cyclosporine, and the statins. Recent breakthroughs in DNA sequencing suggest that millions of fungal species exist on Earth, with each genome encoding pathways capable of generating as many as dozens of natural products. However, the majority of encoded molecules are difficult or impossible to access because the organisms are uncultivable or the genes are transcriptionally silent. To overcome this bottleneck in natural product discovery, we developed the HEx (Heterologous EXpression) synthetic biology platform for rapid, scalable expression of fungal biosynthetic genes and their encoded metabolites in Saccharomyces cerevisiae. We applied this platform to 41 fungal biosynthetic gene clusters from diverse fungal species from around the world, 22 of which produced detectable compounds. These included novel compounds with unexpected biosynthetic origins, particularly from poorly studied species. This result establishes the HEx platform for rapid discovery of natural products from any fungal species, even those that are uncultivable, and opens the door to discovery of the next generation of natural products.

Maternal Zika Virus Disease Severity, Virus Load, Prior Dengue Antibodies, and Their Relationship to Birth Outcomes

Background

Congenital Zika virus (ZIKV) syndrome is a newly identified condition resulting from infection during pregnancy. We analyzed outcome data from a mother-infant cohort in Rio de Janeiro in order to assess whether clinical severity of maternal ZIKV infection was associated with maternal virus load, prior dengue antibodies, or abnormal pregnancy/infant outcomes.

Methods

A clinical severity assessment tool was developed based on duration of fever, severity of rash, multisystem involvement, and duration of symptoms during ZIKV infection. ZIKV-RNA load was quantified by polymerase chain reaction (PCR) cycles in blood/ urine. Dengue immunoglobulin G (IgG) antibodies were measured at baseline. Adverse outcomes were defined as fetal loss or a live infant with grossly abnormal clinical or brain imaging findings. Regression models were used to study potential associations.

Results

131 ZIKV-PCR positive pregnant women were scored for clinical disease severity, 6 (4.6%) had mild disease, 98 (74.8%) had moderate disease, and 27 (20.6%) severe manifestations of ZIKV infection. There were 58 (46.4%) abnormal outcomes with 9 fetal losses (7.2%) in 125 pregnancies. No associations were found between: disease severity and abnormal outcomes (P = .961; odds ratio [OR]: 1.00; 95% confidence interval [CI]: 0.796-1.270); disease severity and viral load (P = .994); viral load and adverse outcomes (P = .667; OR: 1.02; 95% CI: 0.922-1.135); or existence of prior dengue antibodies (88% subjects) with severity score, ZIKV-RNA load or adverse outcomes (P = .667; OR: 0.78; 95% CI: 0.255-2.397).

Conclusions

Congenital ZIKV syndrome does not appear to be associated with maternal disease severity, ZIKV-RNA load at time of infection or existence of prior dengue antibodies.

Decoding gene patents in Australia

Patents directed to naturally occurring genetic material, such as DNA, RNA, chromosomes, and genes, in an isolated or purified form have been granted in Australia for many years. This review provides scientists with a summary of the gene patent debate from an Australian perspective and specifically reviews how the various levels of the legal system as they apply to patents-the Australian Patent Office, Australian courts, and Australian government-have dealt with the issue of whether genetic material is proper subject matter for a patent.

Abstract 3265: Immortalization and comprehensive characterization of a human ovarian adenocarcinoma cell line derived from an Ashkenazi Jewish patient

We have established and characterized a new ovarian cancer cell line derived from stage IV serous ovarian adenocarcinoma metastatic tissue from a 47 year old Ashkenazi Jewish patient. The patient developed ovarian cancer at age 44 and died of the disease at age 48. The tissue was obtained after an extensive secondary cytoreductive intraperitoneal surgery. Prior to the surgery the patient underwent primary cytoreduction followed by several systemic therapies with recurrences. A culture of the metastatic tissue was transfected with Simian Virus 40 Large T-Antigen and telomerase. The cell line has been in culture on and off during 3 years.

The identity of the cell line was confirmed by Short Tandem Repeat genotyping on genomic DNA extracted from early and late passages as well as from frozen metastatic tissue. The cell line was further characterized by array-Comparative Genomic Hybridization and gene expression microarray; and by Spectral Karyotyping and Fluorescent In Situ Hybridization. The results of these analyses were compared, when appropriate, with those of frozen metastatic tissue. A low level of genetic instability was detected in the cell line, but the karyotypes seem to be near diploid and relatively stable, after several years of cultivation.

We believe that this novel ovarian cancer cell line could contribute to the understanding of the molecular genetic basis of the disease in this advanced stage, and be representative of the tumors of a great number of patients that become resistant to the majority if not all known cancer therapies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3265.

Substrate specificity of family 5, 6, 7, 9, 12, and 45 endoglucanases

Endoglucanases are important enzymes for biomass conversion and other industrial processes. Determining the specificity of endoglucanases from various glycoside hydrolase families is of interest for bioinformatic functional prediction and substrate-tailored enzyme development. To do so, we characterized approximately 30 endoglucanases from six glycoside hydrolase families. For p-nitrophenyl cellobioside and lactoside, only family 7 enzymes showed significant activity. For xyloglucan, both family 7 and 12 enzymes showed significant activity. For xylan and arabinoxylan, only family 7 enzymes showed significant activity. For mannan and galactomannan, both family 5 and 9 enzymes showed significant activity. The difference in specificity was preliminarily attributed mainly to the structural difference of the enzymes' active sites. For family 7 endoglucanases, difference in thermal stability might affect their performance in hydrolyzing various (hemi)cellulose substrates. Phylogenetic analysis on the subfamily distribution of family 5 endoglucanases (in relation with mannanases) suggested that their mannanase side-activity might be the remnant of an ancestral multi-function enzyme. Similar analysis was also made with the xyloglucanase or arabionxylans side-activity of family 12 and 7 endoglucanases. The apparent dependence of the specificity on family (primary/tertiary structure) might assist us in better understanding the structure-function relationship of the enzymes, and developing more versatile biocatalysts for the utilization of biomass.

Visualization and identification of IL-7 producing cells in reporter mice

Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein ) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging.

Aryl hydrocarbon receptor expression is associated with a family history of upper gastrointestinal tract cancer in a high-risk population exposed to aromatic hydrocarbons

BACKGROUND

Polycyclic aromatic hydrocarbon (PAH) exposure is a risk factor for esophageal squamous cell carcinoma, and PAHs are ligands of the aryl hydrocarbon receptor (AhR). This study measured the expression of AhR and related genes in frozen esophageal cell samples from patients exposed to different levels of indoor air pollution, who did or did not have high-grade squamous dysplasia and who did or did not have a family history of upper gastrointestinal tract (UGI) cancer.

METHODS

147 samples were evaluated, including 23 (16%) from patients with high-grade dysplasia and 48 (33%) from patients without dysplasia who heated their homes with coal, without a chimney (a "high" indoor air pollution group), and 27 (18%) from patients with high-grade dysplasia and 49 (33%) from patients without dysplasia who did not heat their homes at all (a "low" indoor air pollution group). Sixty-four (44%) had a family history of UGI cancer. RNA was extracted and quantitative PCR analysis was done.

RESULTS

AhR gene expression was detectable in 85 (58%) of the samples and was >9-fold higher in those with a family history of UGI cancer [median expression (interquartile range), -1,964 (-18,000, -610) versus -18,000 (-18,000, -1036); P = 0.02, Wilcoxon rank-sum test]. Heating status, dysplasia category, age, gender, and smoking were not associated with AhR expression (linear regression; all P values >or= 0.1).

CONCLUSION

AhR expression was higher in patients with a family history of UGI cancer. Such individuals may be more susceptible to the deleterious effects of PAH exposure, including PAH-induced cancer.

Accelerated preclinical testing using transplanted tumors from genetically engineered mouse breast cancer models

PURPOSE

The use of genetically engineered mouse (GEM) models for preclinical testing of anticancer therapies is hampered by variable tumor latency, incomplete penetrance, and complicated breeding schemes. Here, we describe and validate a transplantation strategy that circumvents some of these difficulties.

EXPERIMENTAL DESIGN

Tumor fragments from tumor-bearing MMTV-PyMT or cell suspensions from MMTV-PyMT, -Her2/neu, -wnt1, -wnt1/p53(+/-), BRCA1/p53(+/-), and C3(1)T-Ag mice were transplanted into the mammary fat pad or s.c. into naïve syngeneic or immunosuppressed mice. Tumor development was monitored and tissues were processed for histopathology and gene expression profiling. Metastasis was scored 60 days after the removal of transplanted tumors.

RESULTS

PyMT tumor fragments and cell suspensions from anterior glands grew faster than posterior tumors in serial passages regardless of the site of implantation. Microarray analysis revealed genetic differences between these tumors. The transplantation was reproducible using anterior tumors from multiple GEM, and tumor growth rate correlated with the number of transplanted cells. Similar morphologic appearances were observed in original and transplanted tumors. Metastasis developed in >90% of mice transplanted with PyMT, 40% with BRCA1/p53(+/-) and wnt1/p53(+/-), and 15% with Her2/neu tumors. Expansion of PyMT and wnt1 tumors by serial transplantation for two passages did not lead to significant changes in gene expression. PyMT-transplanted tumors and anterior tumors of transgenic mice showed similar sensitivities to cyclophosphamide and paclitaxel.

CONCLUSIONS

Transplantation of GEM tumors can provide a large cohort of mice bearing mammary tumors at the same stage of tumor development and with defined frequency of metastasis in a well-characterized molecular and genetic background.

Mucosal tolerance to E-selectin and response to systemic inflammation

Mucosal tolerance to E-selectin has been shown to prevent stroke and reduce brain infarcts in experimental stroke models. However, the effective E-selectin dose range required to achieve mucosal tolerance and the precise mechanisms of neuroprotection remain unclear. We sought to examine the mechanisms of cytoprotection using gene expression profiling of tissues in the setting of mucosal tolerance and inflammatory challenge. Using spontaneously hypertensive rats (SHRs), we achieved immune tolerance with 0.1 to 5 microg E-selectin per nasal instillation and observed a dose-related anti-E-selectin immunoglobulin G antibody production. We also show the distinct patterns of gene expression changes in the brain and spleen with the different tolerizing doses and lipopolysaccharide (LPS) exposure. Prominent differences were seen with such genes as insulin-like growth factors in the brain and downregulation of those encoding the major histocompatibility complex class I molecules in the spleen. In all, mucosal tolerance to E-selectin and subsequent exposure to LPS resulted in significant tissue changes. These changes, while giving an insight to the underlying mechanisms, serve as possible targets for future studies to facilitate translation to human clinical trials.

Regulation of ITAM-positive receptors: role of IL-12 and IL-18

Our previous studies have identified mechanisms by which cytokine production, blocked by Ly49G2 receptor cross-linking, can be overridden. In this study we analyzed the regulation of other ITAM-positive receptor signaling on NK, NKT, and T cells and characterized the biochemical pathways involved in this signaling. Our studies demonstrate that cross-linking of NKG2D and NK1.1 results in a synergistic NK IFN-gamma response when combined with IL-12 or IL-18. Examination of NKT- and T-cell responses demonstrated that cross-linking of NKG2D and CD3 resulted in potent synergy when combined with IL-12 and, to a lesser degree, with IL-18. We have now found that both the p38 MAP kinase and the ERK-dependent signal transduction pathways are required for the synergistic response. Further mechanistic examination of the synergy indicated a potent up-regulation of total IFN-gamma mRNA in the nuclear and the cytoplasmic compartment, but mRNA half-life was not affected. Fifteen minutes of IL-12 pretreatment was sufficient to result in maximal synergistic activation, indicating that the response of the cells to the IL-12 signal was rapid and immediate. Thus, our data demonstrate that multiple convergent signals maximize the innate immune response by triggering complementary biochemical signaling pathways.

Infectious enteritis after intestinal transplantation: incidence, timing, and outcome

AIM

To review the incidence, timing, and outcome of infectious enteritis after intestinal transplantation (IT).

METHOD

A retrospective review of all patients undergoing IT at a single institution between 1991 and 2003 was analyze with standard statistical tools.

RESULTS

Among 33 IT recipients, 13 (39%) developed 20 culture- or biopsy-proven episodes of infectious enteritis. The recipient demographics were 77% men and median age 2.6 years. Infections were diagnosed at a median of 76 days (32 to 1800) after IT. There were 14 viral (CMV one, rotavirus eight, adenovirus four, EBV one, three bacterial (Clostridium difficile), and three other infections (Giardia lamblia one, cryptosporidium two). Complete resolution was achieved in 17 (94%) infectious after appropriate antimicrobial or conservative therapy. Interestingly, there were six rejection episodes following infectious enteritis. Grafts were lost to rejection after rotaviral enteritis (n = 1) and adenoviral enteritis misdiagnosed as rejection (n = 1). Patient and graft survival were not adversely affected by infections.

CONCLUSIONS

Infectious enteritis occurs frequently after IT. Viral agents are the cause in two-thirds of cases. With supportive care and appropriate treatment, resolution is possible in the majority of cases. Differentiating rejection and infection by histopathology can be difficult.

Effect of a natural contaminant on foam fractionation of bromelain

Foam fractionation is a simple, inexpensive method for separating and purifying proteins. Typically, a dilute bromelain solution with a pH ranging from 2.0 to 7.0 foams very well when bubbles are introduced into a foam fractionation column. It was observed, however, that the dilute enzyme solution only foamed between approximately pH 2.0 and 3.0 when the inner wall of the fractionation column was coated with a natural contaminant (okra residue). We studied the separation ratio and the protein mass recovery to explore the effect of a natural antifoaming agent on the foam fractionation of a dilute bromelain solution. The control variables used in this process were the initial bulk solution pH, which ranged from 2.0 to 7.0, and the superficial air velocity, which varied between 1.7 and 6.2 cm/s.

Fast-tracking older people through A&E

This article explores the concept and feasibility of fast-tracking older people through A&E services to enable appropriate admission and quality responsive patient care. It illustrates how an academic assignment undertaken as part of a pre-registration programme could be adapted for publication to challenge thinking and encourage examination of potential new ways of working.

The cyclic AMP system and Drosophila learning

The cyclic AMP (cAMP) system plays a critical role in olfactory learning in the fruit fly, Drosophila melanogaster, as evidenced by the following: [1] The dunce gene encodes a form of cAMP phosphodiesterase (PDE). Flies carrying mutations at this gene show reduced PDE activity, high cAMP levels, and deficits in olfactory learning and memory [2]. The rutabaga gene encodes one type of adenylyl cyclase (AC) similar in properties to the Type I AC characterized from vertebrate brain. This enzyme is activated by G-protein and Ca++ and has been postulated to be a molecular coincidence detector, capable of integrating information from two independent sources such as the conditioned stimulus (CS) and the unconditioned stimulus (US) delivered to animals during Pavlovian conditioning. Rutabaga mutant flies are deficient in AC activity and show behavioral defects similar to those exhibited by dunce mutants [3]. Flies carrying mutations in the gene (DC0) that encodes the catalytic subunit of protein kinase A (PKA), the major mediator of cAMP actions, show alterations in learning performance and a loss in PKA activity. All three genes are expressed preferentially in mushroom bodies, neuroanatomical sites that mediate olfactory learning. Interestingly, the PDE and the catalytic subunit of PKA are found primarily in axonal and dendritic compartments of the mushroom body cells, whereas the AC is found primarily in the axonal compartment. The reason for this differential compartmentalization is unclear, although the hypothetical role of AC as coincidence detector would predict that CS and US stimuli are integrated in the axonal compartment. These observations suggest that cAMP is a dominant second messenger utilized by mushroom body cells to modulate their physiology while the animal is learning and consolidating memory. However, many other types of molecules are likely involved in the physiological alterations that occur in these cells during learning, including cell surface proteins, transcription factors, and synaptic proteins.

Ten unanswered questions regarding comprehensive school health promotion

The past two decades witnessed dramatic growth in support for comprehensive school health promotion. Yet, many questions about its effectiveness and feasibility remain unanswered. This article poses several research and policy questions, the answers to which may help to shape the future of school health programs in this country.

Vitamin K status of lactating mothers, human milk, and breast-feeding infants

Hemorrhagic disease of the newborn is a disease of breast-feeding newborns. There is little information on longitudinal breast milk concentrations of phylloquinone (vitamin K1) or the effects of maternal phylloquinone supplements on breast milk. In study part 1, 11 lactating mothers, who received 20 mg of phylloquinone orally, had rises in plasma (less than 1 to 64.2 +/- 31.5 ng/mL by 6 hours) and breast milk concentrations (from 1.11 +/- 0.82 to 130 +/- 188 ng/mL by 12 hours). In part 2, 23 lactating mothers and their infants were observed longitudinally along with a formula-fed control group of infants (n = 11). Mean breast milk concentrations of phylloquinone at 1, 6, 12, and 26 weeks were 0.64 +/- 0.43, 0.86 +/- 0.52, 1.14 +/- 0.72, and 0.87 +/- 0.50 ng/mL, respectively, in the infants fed human milk. Maternal phylloquinone intakes (72-hour dietary recalls) exceeded the recommended daily allowance of 1 microgram/kg per day. Infant phylloquinone intakes did not achieve the recommended daily allowance of 1 microgram/kg per day in any infant. Plasma phylloquinone concentrations in the infants fed human milk remained extremely low (mean less than 0.25 ng/mL) throughout the first 6 months of life compared with the formula-fed infants (4.39 to 5.99 ng/mL). In this small sample, no infant demonstrated overt vitamin K deficiency. Despite very low plasma phylloquinone concentrations, vitamin K supplements (other than in the immediate newborn period) cannot be recommended for exclusively breast-fed infants based on these data.

Effect of ascorbic acid on the disease caused by Escherichia coli challenge infection

In a series of experiments, leghorn-type chickens were fed diets containing from 0 to 880 mg of ascorbic acid/kg of feed beginning 1 day before air-sac challenge with Escherichia coli. Infection occurred in 46/60 (76%) of the controls and in 12/63 (19%) of those given feed containing 330 mg of ascorbic acid/kg. Levels of ascorbic acid above and below 330 mg/kg feed were less effective.

Peripheral neuropathy of dietary riboflavin deficiency in chickens

A strain of rapidly growing meat-type chickens was fed a diet deficient in riboflavin from 1-40 days of age. Diminished growth rate, progressive gait abnormality and reluctance to move were noted beginning on day 8. Neurologic abnormalities were related to peripheral neuropathy characterized by Schwann cell hypertrophy and degeneration with cytoplasmic lipid droplets' and segmental demyelination. Lesions were initially detected on day 10, and in concert with clinical signs became more profound between days 14 and 21. Sequestration of myelin debris within Schwann cells was common. Other features of the neuropathy included the presence of endoneurial edema and axonal degeneration involving small numbers of fibers. Remyelination of peripheral nerve fibers in birds on the deficient diet was occasionally seen on day 10, became progressively more prominent, and was marked by day 37. There was an associated, variable but incomplete, clinical improvement evident in later stages of the study. Liver concentrations of riboflavin in deficient birds were significantly reduced on day 13 but not on day 26. This neuropathy may be related to diminished tissue levels of the riboflavin-based coenzymes flavin-adenine dinucleotide (FAD) and flavin mononucleotide (FMN) leading to reduced cellular energy levels and profoundly affecting Schwann cells at some critical point in growth.

Renal capsular lipoma

Renal capsular lesions are rare. Selective angiography remains the best means to identify a suspected capsular mass. We report a case of renal capsular lipoma and review the radiographical findings.

Effect of transitional photoperiods on testicular development and puberty in male deer mice (Peromyscus maniculatus)

In a series of five experiments, young male deer mice (Peromyscus maniculatus bairdii) were exposed to photoperiods ranging in length from 3 to 19 h per 24-h period, as well as to constant light and constant darkness. Reproductive organ growth as measured at 6 weeks of age was inhibited by less than or equal to 11.5 h of light. In males receiving 11.5-19 h of light, there was a quantitative increase in reproductive organ size as a function of photoperiod. Rather than a 'critical' photoperiod partitioning reproductive inhibition and stimulation, there was a zone of gradual transition from inhibition to full stimulation. Histological analysis of testes demonstrated that spermatogenesis was stimulated by long photoperiods. Examination of the epidermal surface of the penis by scanning electron microscopy indicated that penile spine development was also regulated by photoperiod.

Influence of melatonin on pubertal development in male deer mice (Peromyscus maniculatus)

The role of melatonin in pubertal development was assessed in male deer mice (Peromyscus maniculatus bairdii) exposed to photoperiodic and social stimuli. Exogenous melatonin retarded puberty in males reared in a long photoperiod, but was without effect in males reared in short days. Melatonin did not retard pubertal development induced by exposure of short-day males to an adult female. These results suggest that pineal melatonin mediates photoperiodic, but not social, control of pubertal development.

Involvement of the circadian system in photoperiodic control of pubertal development in female deer mice, Peromyscus maniculatus

Pubertal development in female deer mice, Peromyscus maniculatus, was stimulated by exposure to light cycles of LD 16:8, LD 6:30 or LD 6:54, but not by exposure to cycles of LD 6:18 or LD 6:42. These results support the hypothesis that female deer mice use a circadian rhythm of responsiveness to light to measure photoperiodic time.

Photoperiodic stimulation of pubertal development in male deer mice: involvement of the circadian system

Pubertal development in prairie deer mice (Peromyscus maniculatus bairdii) is accelerated by exposure of juveniles to a long-day photoperiod, and, conversely, retarded by exposure to short days. The purpose of the present study was to evaluate the possible involvement of the circadian system in the photoperiodic regulation of puberty. Weanling males, previously housed on a short-day light cycle of 6L:18D, were subjected to a "resonance" protocol in which they received one of the following light cycles: 6L:18D, 6L:30D, 6L:42D, 6L:54D, or 16L:8D. Post-weaning exposure to cycles of 16L:8D, 6L:30D, and 6L:54D stimulated reproductive organ growth as measured at 6 weeks of age. Exposure to cycles of 6L:18D and 6L:42D failed to stimulate reproductive development. These data support the hypothesis that young male deer mice use a circadian rhythm of responsiveness to light to measure photoperiodic time and, consequently, regulate pubertal development.

Decreased lymphocyte transformation to vaccinia virus in multiple sclerosis

Lymphocyte transformation to vaccinia virus was measured in multiple sclerosis (MS) patients and normal controls. There was a significant reduction of lymphocyte transformation to vaccinia virus in multiple sclerosis patients compared with the control group. In addition, a positive correlation existed between the degree of disability of the multiple sclerosis patients and the extent of lymphocyte transformation in the presence of vaccinia virus. There was no correlation between cell-mediated immunity to vaccinia virus and either serum or cerebrospinal fluid (CSF) antibody levels to vaccinia in multiple sclerosis patients or controls, all of whom had been previously vaccinated. In conjunction with other studies, all of whom had been previously vaccinated. In conjunction with other studies that have demonstrated elevated antibody titers to vaccinia virus in the CSF of multiple sclerosis patients, these results support the possibility that vaccinia virus may play a role in the pathogenesis of multiple sclerosis.