A Phase I/II Trial of HER2 Vaccine-Primed Autologous T-Cell Infusions in Patients with Treatment Refractory HER2-Overexpressing Breast Cancer

PURPOSE

High levels of type I T cells are needed for tumor eradication. We evaluated whether the HER2-specific vaccine-primed T cells are readily expanded ex vivo to achieve levels needed for therapeutic infusion.

PATIENTS AND METHODS

Phase I/II nonrandomized trial of escalating doses of ex vivo-expanded HER2-specific T cells after in vivo priming with a multiple peptide-based HER2 intracellular domain (ICD) vaccine. Vaccines were given weekly for a total of three immunizations. Two weeks after the third vaccine, patients underwent leukapheresis for T-cell expansion, then received three escalating cell doses over 7- to 10-day intervals. Booster vaccines were administered after the T-cell infusions. The primary objective was safety. The secondary objectives included extent and persistence of HER2-specific T cells, development of epitope spreading, and clinical response. Patients received a CT scan prior to enrollment and 1 month after the last T-cell infusion.

RESULTS

Nineteen patients received T-cell infusions. Treatment was well tolerated. One month after the last T-cell infusion, 82% of patients had significantly augmented T cells to at least one of the immunizing epitopes and 81% of patients demonstrated enhanced intramolecular epitope spreading compared with baseline (P < 0.05). There were no complete responses, one partial response (6%), and eight patients with stable disease (47%), for a disease control rate of 53%. The median survival for those with progressive disease was 20.5 months and for responders (PR+SD) was 45.0 months.

CONCLUSIONS

Adoptive transfer of HER2 vaccine-primed T cells was feasible, was associated with minimal toxicity, and resulted in an increased overall survival in responding patients. See related commentary by Crosby et al., p. 3256.

Expansion of Disease Specific Cardiac Macrophages in Immune Checkpoint Inhibitor Myocarditis

Background

Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have revolutionized cancer management but are associated with devastating immune-related adverse events (irAEs) including myocarditis. The main risk factor for ICI myocarditis is the use of combination PD-1 and CTLA4 inhibition. ICI-myocarditis is often fulminant and is pathologically characterized by myocardial infiltration of T lymphocytes and macrophages. While much has been learned regarding the role of T-cells in ICI-myocarditis, little is understood regarding the identity, transcriptional diversity, and functions of infiltrating macrophages.

Methods

We employed an established murine ICI myocarditis model ( Ctla4 +/- Pdcd1 -/- mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, flow cytometry, in situ RNA hybridization and molecular imaging and antibody neutralization studies.

Results

We observed marked increases in CCR2 + monocyte-derived macrophages and CD8 + T-cells in this model. The macrophage compartment was heterogeneous and displayed marked enrichment in an inflammatory CCR2 + subpopulation highly expressing Cxcl9 , Cxcl10 , Gbp2b , and Fcgr4 that originated from CCR2 + monocytes. Importantly, a similar macrophage population expressing CXCL9 , CXCL10 , and CD16α (human homologue of mouse FcgR4) was found selectively expanded in patients with ICI myocarditis compared to other forms of heart failure and myocarditis. In silico prediction of cell-cell communication suggested interactions between T-cells and Cxcl9 + Cxcl10 + macrophages via IFN-γ and CXCR3 signaling pathways. Depleting CD8 + T-cells, macrophages, and blockade of IFN-γ signaling blunted the expansion of Cxcl9 + Cxcl10 + macrophages in the heart and attenuated myocarditis suggesting that this interaction was necessary for disease pathogenesis.

Conclusion

These data demonstrate that ICI-myocarditis is associated with the expansion of a specific population of IFN-γ induced inflammatory macrophages and suggest the possibility that IFN-γ blockade may be considered as a treatment option for this devastating condition.

Differential T-cell and Antibody Responses induced by mRNA versus adenoviral vectored COVID-19 vaccines in Patients with Immunodeficiencies

Background

Immunodeficient patients (IDPs) are at higher risk of contracting severe COVID-19 disease. Targeted vaccination strategies have been implemented to enhance vaccine-induced protection. In this population however, clinical effectiveness is variable and duration of protection unknown.

Objective

To understand the cellular and humoral immune responses to mRNA and adenoviral vectored COVID-19 vaccines in patients with immunodeficiency.

Methods

Immune responses to SARS-COV-2 spike were assessed after two doses of homologous ChAdOx1-nCoV-19 or BNT162b2 vaccines in 112 infection-naïve IDPs and 131 healthy health care workers (HCWs) as controls. Predictors of vaccine responsiveness were investigated.

Results

Immune responses to vaccination were low, and viral neutralisation by antibody not detected despite high titre binding responses in many IDPs. In those responding, the frequency of specific T-cell responses in IDPs was similar to controls whilst antibody responses were lower. Sustained vaccine specific differences were identified: T-cell responses were greater in ChAdOx1-nCoV-19 compared with BNT162b2 immunised IDPs and antibody binding and neutralisation was greater in all cohorts immunised with BNT162b2. The positive correlation between T-cell and antibody responses was weak and increased with subsequent vaccination.

Conclusion

Immunodeficient patients have impaired immune responses to mRNA and viral vector COVID-19 vaccines that appear influenced by vaccine formulation. Understanding the relative roles of T-cell and antibody mediated protection and potential of heterologous prime and boost immunization protocols is needed to optimise the vaccination approach in these high-risk groups.

NK- and T-cell granzyme B and K expression correlates with age, CMV infection and influenza vaccine-induced antibody titres in older adults

Granzymes are a family of serine-proteases that act as critical mediators in the cytolytic and immunomodulatory activities of immune cells such as CD8⁺ T-cells and natural killer (NK) cells. Previous work indicates that both granzyme B (GZB) and K (GZK) are increased with age in CD8⁺ T-cells, and in the case of GZB, contribute to dysfunctional immune processes observed in older adults. Here, we sought to determine how GZB and GZK expression in NK-cells, and CD4⁺, CD8⁺, and gamma-delta T-cells, quantified in terms of positive cell frequency and mean fluorescence intensity (MFI), differed with age, age-related health-traits and the antibody response to high-dose influenza vaccine. We found that the frequency and MFI of GZB-expressing NK-cells, and CD8⁺ and Vδ1+ T-cells, and GZK-expressing CD8⁺ T-cells was significantly higher in older (66-97 years old; n = 75) vs. younger (24-37 years old; n = 10) adults by up to 5-fold. There were no significant associations of GZB/GZK expression with sex, frailty or plasma levels of TNF or IL-6 in older adults, but those who were seropositive for cytomegalovirus (CMV) exhibited significantly higher frequencies of GZB+ NK-cells, and CD4⁺, CD8⁺ and Vδ1+ T-cells, and GZK+ CD8⁺ T-cells (Cohen's d = .5-1.5). Pre-vaccination frequencies of GZB+ NK-cells were positively correlated with vaccine antibody responses against A/H3N2 (d = .17), while the frequencies of GZK+ NK and CD8⁺ T-cells were inversely associated with A/H1N1 (d = -0.18 to -0.20). Interestingly, GZK+ NK-cell frequency was inversely correlated with pre-vaccination A/H1N1 antibody titres, as well as those measured over the previous 4 years, further supporting a role for this subset in influencing vaccine antibody-responses. These findings further our understanding of how granzyme expression in different lymphoid cell-types may change with age, while suggesting that they influence vaccine responsiveness in older adults.

Perspectives on and Quality of Life in Skin of Color Patients With Mycosis Fungoides/Sézary Syndrome: A Qualitative Analysis

Background Prior quantitative studies have described the diminished health-related quality of life (HRQoL) faced by the overall mycosis fungoides (MF)/Sézary syndrome (SS) population; yet, little is known about how the disease affects HRQoL in skin of color (SOC) patients. This qualitative study sought to explore the lived experiences of SOC patients with MF/SS and gain deeper insights into the impact the disease has on various facets of HRQoL.  Methodology Interviews with SOC patients with MF/SS ≥18 were recruited from a cutaneous lymphoma clinic. A thematic analysis was performed to identify overarching themes. Results Ten patients were invited to participate from July to September 2021. One patient with SS and seven patients with MF (four in the early stage and four in the advanced stage), with a median age of 60.5 years, agreed to participate. Emerging themes included diagnostic and therapeutic delays frequently due to initial misdiagnoses with other skin conditions. Physical and functional burdens significantly hindered participants' abilities to carry out daily responsibilities and maintain employment, and impacts on physical appearance (e.g., darkened skin) led to increased self-consciousness and lack of social acceptance. Participants regarded family and faith as main sources of support in addition to developing healthy coping strategies, such as self-acceptance and adaptability. All participants reported feeling satisfied with their access to healthcare information and the quality of care received. Conclusions Our findings provide greater insights into how HRQoL is impacted across SOC patients with MF/SS, which can help raise awareness among healthcare providers and assist with creating interdisciplinary healthcare approaches to better support the needs of this population.

T-cell cellular stress and reticulocyte signatures, but not loss of naïve T lymphocytes, characterize severe COVID-19 in older adults

In children and younger adults up to 39 years of age, SARS-CoV-2 usually elicits mild symptoms that resemble the common cold. Disease severity increases with age starting at 30 and reaches astounding mortality rates that are ~330 fold higher in persons above 85 years of age compared to those 18-39 years old. To understand age-specific immune pathobiology of COVID-19 we have analyzed soluble mediators, cellular phenotypes, and transcriptome from over 80 COVID-19 patients of varying ages and disease severity, carefully controlling for age as a variable. We found that reticulocyte numbers and peripheral blood transcriptional signatures robustly correlated with disease severity. By contrast, decreased numbers and proportion of naïve T-cells, reported previously as a COVID-19 severity risk factor, were found to be general features of aging and not of COVID-19 severity, as they readily occurred in older participants experiencing only mild or no disease at all. Single-cell transcriptional signatures across age and severity groups showed that severe but not moderate/mild COVID-19 causes cell stress response in different T-cell populations, and some of that stress was unique to old severe participants, suggesting that in severe disease of older adults, these defenders of the organism may be disabled from performing immune protection. These findings shed new light on interactions between age and disease severity in COVID-19.

Effects of Malaria and HIV Infection on Anemia and T-cells Levels in Children in Douala City, Cameroon

Introduction Human immunodeficiency virus (HIV) infection and malaria are priority health issues for sub-Saharan Africa. Both diseases worsen each other through their effect on the immune and hematological systems. This study aimed to determine the effects of HIV infection and asymptomatic malaria on anemia and T-cells counts in children in the city of Douala in the republic of Cameroon. Method From May to November 2016, 197 HIV infected and 98 HIV-free non-febrile children up to 19 years old (128 male and 167 female) participated in the study. All HIV-infected children were receiving antiretroviral treatment and co-trimoxazole. Malaria diagnosis was performed using Giemsa-stained thick blood film; immunological and hematological parameters were assessed through a flow cytometer and an automated analyzer respectively. Chi-squared or Fischer's exact tests was used to compare the proportions, Mann-Whitney and ANOVA tests were used for the means. Statistical significance was set at p˂0.05. Results The prevalence of malaria was 8.8%, and that of anemia was 40.7%. CD4⁺-T cells were higher in malaria-infected children, both in HIV positive and negative (p=0.049). No significant association was found between malaria parasitemia and CD8⁺-T cell levels, both in HIV-positive and negative children (p=0.41). Anemia was higher in HIV-positive children (p=0.019), especially in those with severe immunosuppression (p=0.001) and in younger children (p=0.0083). Children on HIV treatment presented lower malaria prevalence (8.6% versus 10.10%), though the difference was not significant (p=0.7068). Malaria infection was associated with lower hemoglobin levels (10.5±1.7 versus 11.2±1.4; p=0.016). Conclusion Malaria infection may enhance CD4⁺-T cells. Both malaria and HIV infection lead to a drop in hemoglobin levels. The HIV treatment protocol may reduce malaria prevalence.

Infections in the monogenic autoimmune syndrome APECED

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is caused by mutations in the Autoimmune Regulator (AIRE) gene, which impair the thymic negative selection of self-reactive T-cells and underlie the development of autoimmunity that targets multiple endocrine and non-endocrine tissues. Beyond autoimmunity, APECED features heightened susceptibility to certain specific infections, which is mediated by anti-cytokine autoantibodies and/or T-cell driven autoimmune tissue injury. These include the 'signature' APECED infection chronic mucocutaneous candidiasis (CMC), but also life-threatening coronavirus disease 2019 (COVID-19) pneumonia, bronchiectasis-associated bacterial pneumonia, and sepsis by encapsulated bacteria. Here we discuss the expanding understanding of the immunological mechanisms that contribute to infection susceptibility in this prototypic syndrome of impaired central tolerance, which provide the foundation for devising improved diagnostic and therapeutic strategies for affected patients.

Targeting the cutaneous lymphocyte antigen (CLA) in inflammatory and neoplastic skin conditions

Introduction: The cutaneous lymphocyte antigen interacts with E-selectin on endothelial cells and is expressed on 15% of circulating T-cells. Skin-homing T-cells express the cutaneous lymphocyte antigen and play a role in local cutaneous immunity in inflammatory reactions and neoplastic conditions.Areas covered: Lymphocyte extravasation is the essential para-physiological mechanism enabling immune surveillance of tissues for tumors as well as effector cell recruitment to inflammatory sites.The authors focused on skin inflammatory disorders, on cutaneous lymphoproliferative disease, and on other skin malignancies.Expert opinion: Interfering with leukocyte extravasation has been regarded as an attractive strategy in skin disorders, in the past for inflammatory conditions and more recently for cutaneous T-cell lymphomas. Therapeutic blocking of skin-homing interactions has been attempted in psoriasis and atopic dermatitis and has been achieved in the treatment of cutaneous T-cell lymphomas. Cutaneous lymphocyte antigen is a potential molecular target for both systemic and skin-directed therapy for cutaneous T-cell lymphomas.

Association of tumor-infiltrating T-cell density with molecular subtype, racial ancestry and clinical outcomes in prostate cancer

The inflammatory microenvironment plays an important role in the pathogenesis and progression of tumors and may be associated with somatic genomic alterations. We examined the association of tumor-infiltrating T-cell density with clinical-pathologic variables, tumor molecular subtype, and oncologic outcomes in surgically treated primary prostate cancer occurring in patients of European-American or African-American ancestry. We evaluated 312 primary prostate tumors, enriched for patients with African-American ancestry and high grade disease. Tissue microarrays were immunostained for CD3, CD8, and FOXP3 and were previously immunostained for ERG and PTEN using genetically validated protocols. Image analysis for quantification of T-cell density in tissue microarray tumor spots was performed. Automated quantification of T-cell densities in tumor-containing regions of tissue microarray spots and standard histologic sections were correlated (r = 0.73, p < 0.00001) and there was good agreement between visual and automated T-cell density counts on tissue microarray spots (r = 0.93, p < 0.00001). There was a significant correlation between CD3+, CD8+, and FOXP3+ T-cell densities (p < 0.00001), but these were not associated with most clinical or pathologic variables. Increased T-cell density was significantly associated with ERG positivity (median 309 vs. 188 CD3+ T cells/mm2; p = 0.0004) and also with PTEN loss (median 317 vs. 192 CD3+ T cells/mm2; p = 0.001) in the combined cohort of matched European-American and African-American ancestry patients. The same association or a similar trend was present in patients of both ancestries when analyzed separately. When the African-American patients from the matched race set were combined with a separate high grade set of African-American cases, there was a weak association of increased FOXP3+ T-cell densities with increased risk of metastasis in multivariable analysis. Though high T-cell density is associated with specific molecular subclasses of prostate cancer, we did not find an association of T-cell density with racial ancestry.

Lymphoid aggregates in desmoplastic melanoma have features of tertiary lymphoid structures

Desmoplastic melanomas (DM) have unique and challenging clinical presentations and histomorphology. A characteristic feature is the presence of scattered lymphoid aggregates. However, the nature of these aggregates is not defined. We hypothesized that they may be tertiary lymphoid structures (TLS), and may be associated with programmed death ligand 1 (PD-L1) expression. We searched our tissue database for 'pure' DMs and for scars as control tissues, collected clinical information, and reviewed H&E histology. We performed multispectral imaging after staining for CD8, CD20, PNAd, FoxP3, CD83, and Ki67, and assessed PD-L1 expression by immunohistochemistry. Pure DM samples were evaluable in 11 patients. All had desmoplastic stroma and lymphoid aggregates on H&E. The lymphoid aggregates of eight of the 11 (72%) DM samples and only three of the 11 scars contained features of TLS, defined as distinct clusters of B cells and CD8 T cells, CD83 dendritic cells in T-cell zones, and PNAd vasculature resembling high endothelial venules. PD-L1 was expressed by at least 1% of melanoma cells in six and by at least 5% of immune cells in 10 of the 11 DM samples. We found that most lymphoid aggregates in DM are organized, classical TLS. PD-L1 expression was detected in most cases and was highest in two cases of DM with TLS. However, low PD-L1 expression in some cases suggests that some DM cells may be unresponsive to interferon-γ. TLS support antigen presentation and T-cell responses in chronic inflammation and cancer. Their presence in DM likely reflects an adaptive immune response, which may be enhanced with immune therapies.

Effects of polyphenols and lipids from Pennisetum glaucum grains on T-cell activation: modulation of Ca(2+) and ERK1/ERK2 signaling

BACKGROUND

Pearl millet (PM), i.e., Pennisetum glaucum, is widely grown in Africa and known for its anti-oxidant and anti-hyperlipidemic properties.

METHODS

The P. glaucum grains were obtained from the region of Ouled Aïssa (South of Algeria). We assessed the effects of phenolic compounds and lipids, extracted from seeds of P. glaucum, on rat lymphocyte proliferation, activated by phorbol 12-myristate 13-acetate and ionomycin. In order to explore signaling pathway, triggered by these compounds, we assessed interleukin-2 (IL-2) mRNA expression and extracellular signal-regulated kinase-1/2 (ERK1/ERK2) phosphorylation. Finally, we determined increases in free intracellular Ca(2+) concentrations, [Ca(2+)]i, by employing Fura-2/AM in rat lymphocytes.

RESULTS

The composition of P. glaucum grains in polyphenols was estimated to be 1660 µg gallic acid equivalents (GAE)/g. Lipids represented 4.5 %, and more than 72% of the fatty acids belonged to unsaturated family. Our investigation showed that both lipid and phenolic compounds inhibited mitogen-induced T-cell proliferation. Compared with phenolic compounds, lipids exerted weaker effects on ERK-1/ERK2 phosphorylation and Ca(2+) signaling in mitogen-activated T-cells.

CONCLUSION

We conclude that the immunomodulatory effects of P. glaucum could be contributed by its phenolic and lipid contents.

Arginase I release from activated neutrophils induces peripheral immunosuppression in a murine model of stroke

Transient suppression of peripheral immunity is a major source of complication for patients suffering from ischemic stroke. The release of Arginase I (ArgI) from activated neutrophils has recently been associated with T-cell dysfunction in a number of pathologies. However, this pathway has not been previously explored in ischemic stroke. Using the murine model of transient middle cerebral artery occlusion, we explored effects of stroke on peripheral T-cell function and evaluated the role of neutrophils and ArgI. Stimulation of splenic T cells from post-stroke animals with anti-CD3/CD28 resulted in decreased proliferation and interferon-γ production when compared with sham-surgery controls. Flow cytometric analysis of intrasplenic leukocytes exposed the presence of a transient population of activated neutrophils that correlated quantitatively with elevated ArgI levels in culture media. In vitro activation of purified resting neutrophils from unmanipulated controls confirmed the capacity for murine neutrophils to release ArgI from preformed granules. We observed decreased expression of the L-arg-sensitive CD3ζ on T cells, consistent with decreased functional activity. Critically, L-arg supplementation restored the functional response of post-stroke T cells to mitogenic stimulation. Together, these data outline a novel mechanism of reversible, neutrophil-mediated peripheral immunosuppression related to ArgI release following ischemic stroke.

Modulation of Trypanosoma cruzi-specific T-cell responses after chemotherapy for chronic Chagas disease

The aim of this review is to describe the contributions of the knowledge of T-cell responses to the understanding of the physiopathology and the responsiveness to etiological treatment during the chronic phase of Chagas disease. T-helper (Th)1 and interleukin (IL)-10 Trypanosoma cruzi-specific T-cells have been linked to the asymptomatic phase or to severe clinical forms of the disease, respectively or vice versa, depending on the T. cruzi antigen source, the patient's location and the performed immunological assays. Parasite-specific T-cell responses are modulated after benznidazole (BZ) treatment in chronically T. cruzi-infected subjects in association with a significant decrease in T. cruzi-specific antibodies. Accumulating evidence has indicated that treatment efficacy during experimental infection with T. cruzi results from the combined action of BZ and the activation of appropriate immune responses in the host. However, strong support of this interaction in T. cruzi-infected humans remains lacking. Overall, the quality of T-cell responses might be a key factor in not only disease evolution, but also chemotherapy responsiveness. Immunological parameters are potential indicators of treatment response regardless of achievement of cure. Providing tools to monitor and provide early predictions of treatment success will allow the development of new therapeutic options.

Effects of atorvastatin and pravastatin on immune activation and T-cell function in antiretroviral therapy-suppressed HIV-1-infected patients

This retrospective study was designed to assess statin effects on T-cell activation from HIV-infected individuals. Peripheral blood mononuclear cells from antiretroviral therapy suppressed HIV-infected individuals receiving atorvastatin or pravastatin were evaluated for T-cell activation, exhaustion and function. Atorvastatin was associated with a significant reduction in CD8 T-cell activation (HLA-DR, CD38/HLA-DR) and exhaustion (TIM-3, TIM-3/PD-1) whereas pravastatin had no effect. In contrast, pravastatin increased antigen specific interferon γ production. These results suggest a differential effect of statins on immune activation and function.

Inhibition of CXCL12 signaling attenuates the postischemic immune response and improves functional recovery after stroke

After stroke, brain inflammation in the ischemic hemisphere hampers brain tissue reorganization and functional recovery. Housing rats in an enriched environment (EE) dramatically improves recovery of lost neurologic functions after experimental stroke. We show here that rats housed in EE after stroke induced by permanent occlusion of the middle cerebral artery (pMCAO), showed attenuated levels of proinflammatory cytokines in the ischemic core and the surrounding peri-infarct area, including a significant reduction in the stroke-induced chemokine receptor CXCR4 and its natural ligand stromal cell-derived factor-1 (CXCL12). To mimic beneficial effects of EE, we studied the impact of inhibiting CXCL12 action on functional recovery after transient MCAO (tMCAO). Rats treated with the specific CXCL12 receptor antagonist 1-[4-(1,4,8,11-tetrazacyclotetradec-1-ylmethyl)phenyl]methyl]-1,4,8,11-tetrazacyclo-tetradecan (AMD3100) showed improved recovery compared with saline-treated rats after tMCAO, without a concomitant reduction in infarct size. This was accompanied by a reduction of infiltrating immune cells in the ischemic hemisphere, particularly cluster of differentiation 3-positive (CD3(+)) and CD3(+)/CD4(+) T cells. Spleen atrophy and delayed death of splenocytes, induced by tMCAO, was prevented by AMD3100 treatment. We conclude that immoderate excessive activation of the CXCL12 pathway after stroke contributes to depression of neurologic function after stroke and that CXCR4 antagonism is beneficial for the recovery after stroke.

Immunity, atherosclerosis and cardiovascular disease

Atherosclerosis, the major cause of cardiovascular disease (CVD), is a chronic inflammatory condition with immune competent cells in lesions producing mainly pro-inflammatory cytokines. Dead cells and oxidized forms of low density lipoproteins (oxLDL) are abundant. The major direct cause of CVD appears to be rupture of atherosclerotic plaques. oxLDL has proinflammatory and immune-stimulatory properties, causes cell death at higher concentrations and contains inflammatory phospholipids with phosphorylcholine (PC) as an interesting epitope. Antibodies against PC (anti-PC) may be atheroprotective, one mechanism being anti-inflammatory. Bacteria and virus have been discussed, but it has been difficult to find direct evidence, and antibiotic trials have not been successful. Heat shock proteins could be one major target for atherogenic immune reactions. More direct causes of plaque rupture include pro-inflammatory cytokines, chemokines, and lipid mediators. To prove that inflammation is a cause of atherosclerosis and CVD, clinical studies with anti-inflammatory and/or immune-modulatory treatment are needed. The potential causes of immune reactions and inflammation in atherosclerosis and how inflammation can be targeted therapeutically to provide novel treatments for CVD are reviewed.

Interleukin-33 upregulation in peripheral leukocytes and CNS of multiple sclerosis patients

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS). Here we document for the first time that the cytokine IL-33 is upregulated in both the periphery and the CNS of MS patients. Plasma IL-33 was elevated in MS patients compared to normal subjects and a three-month treatment of MS patients with interferon β-1a resulted in a significant decrease of IL-33 levels. Similarly, stimulated cultured lymphocytes and macrophages from MS patients had elevated IL-33 levels compared to normal subjects. In parallel, the transcription factor NF-κB that mediates IL-33 transcription was also elevated in leukocytes of MS patients. IL-33 was elevated in normal-appearing white matter and plaque areas from MS brains and astrocytes were identified as an important source of IL-33 expression in the CNS. In summary, IL-33 levels are elevated in the periphery and CNS of MS patients, implicating IL-33 in the pathogenesis of MS.

Efficacy and safety of Sleeping Beauty transposon-mediated gene transfer in preclinical animal studies

Sleeping Beauty (SB) transposons have been effective in delivering therapeutic genes to treat certain diseases in mice. Hydrodynamic gene delivery of integrating transposons to 5-20% of the hepatocytes in a mouse results in persistent elevated expression of the therapeutic polypeptides that can be secreted into the blood for activity throughout the animal. An alternative route of delivery is ex vivo transformation with SB transposons of hematopoietic cells, which then can be reintroduced into the animal for treatment of cancer. We discuss issues associated with the scale-up of hydrodynamic delivery to the liver of larger animals as well as ex vivo delivery. Based on our and others' experience with inefficient delivery to larger animals, we hypothesize that impulse, rather than pressure, is a critical determinant of the effectiveness of hydrodynamic delivery. Accordingly, we propose some alterations in delivery strategies that may yield efficacious levels of gene delivery in dogs and swine that will be applicable to humans. To ready hydrodynamic delivery for human application we address a second issue facing transposons used for gene delivery regarding their potential to "re-hop" from one site to another and thereby destabilize the genome. The ability to correct genetic diseases through the infusion of DNA plasmids remains an appealing goal.

Novel antibody-based proteins for cancer immunotherapy

The relative success of monoclonal antibodies in cancer immunotherapy and the vast manipulation potential of recombinant antibody technology have encouraged the development of novel antibody-based antitumor proteins. Many insightful reagents have been produced, mainly guided by studies on the mechanisms of action associated with complete and durable remissions, results from experimental animal models, and our current knowledge of the human immune system. Strikingly, only a small percent of these new reagents has demonstrated clinical value. Tumor burden, immune evasion, physiological resemblance, and cell plasticity are among the challenges that cancer therapy faces, and a number of antibody-based proteins are already available to deal with many of them. Some of these novel reagents have been shown to specifically increase apoptosis/cell death of tumor cells, recruit and activate immune effectors, and reveal synergistic effects not previously envisioned. In this review, we look into different approaches that have been followed during the past few years to produce these biologics and analyze their relative success, mainly in terms of their clinical performance. The use of antibody-based antitumor proteins, in combination with standard or novel therapies, is showing significant improvements in objective responses, suggesting that these reagents will become important components of the antineoplastic protocols of the future.

Anti-CD8 antibodies can trigger CD8+ T cell effector function in the absence of TCR engagement and improve peptide-MHCI tetramer staining

CD8(+) T cells recognize immunogenic peptides presented at the cell surface bound to MHCI molecules. Ag recognition involves the binding of both TCR and CD8 coreceptor to the same peptide-MHCI (pMHCI) ligand. Specificity is determined by the TCR, whereas CD8 mediates effects on Ag sensitivity. Anti-CD8 Abs have been used extensively to examine the role of CD8 in CD8(+) T cell activation. However, as previous studies have yielded conflicting results, it is unclear from the literature whether anti-CD8 Abs per se are capable of inducing effector function. In this article, we report on the ability of seven monoclonal anti-human CD8 Abs to activate six human CD8(+) T cell clones with a total of five different specificities. Six of seven anti-human CD8 Abs tested did not activate CD8(+) T cells. In contrast, one anti-human CD8 Ab, OKT8, induced effector function in all CD8(+) T cells examined. Moreover, OKT8 was found to enhance TCR/pMHCI on-rates and, as a consequence, could be used to improve pMHCI tetramer staining and the visualization of Ag-specific CD8(+) T cells. The anti-mouse CD8 Abs, CT-CD8a and CT-CD8b, also activated CD8(+) T cells despite opposing effects on pMHCI tetramer staining. The observed heterogeneity in the ability of anti-CD8 Abs to trigger T cell effector function provides an explanation for the apparent incongruity observed in previous studies and should be taken into consideration when interpreting results generated with these reagents. Furthermore, the ability of Ab-mediated CD8 engagement to deliver an activation signal underscores the importance of CD8 in CD8(+) T cell signaling.

Modeling neural immune signaling of episodic and chronic migraine using spreading depression in vitro

Migraine and its transformation to chronic migraine are healthcare burdens in need of improved treatment options. We seek to define how neural immune signaling modulates the susceptibility to migraine, modeled in vitro using spreading depression (SD), as a means to develop novel therapeutic targets for episodic and chronic migraine. SD is the likely cause of migraine aura and migraine pain. It is a paroxysmal loss of neuronal function triggered by initially increased neuronal activity, which slowly propagates within susceptible brain regions. Normal brain function is exquisitely sensitive to, and relies on, coincident low-level immune signaling. Thus, neural immune signaling likely affects electrical activity of SD, and therefore migraine. Pain perception studies of SD in whole animals are fraught with difficulties, but whole animals are well suited to examine systems biology aspects of migraine since SD activates trigeminal nociceptive pathways. However, whole animal studies alone cannot be used to decipher the cellular and neural circuit mechanisms of SD. Instead, in vitro preparations where environmental conditions can be controlled are necessary. Here, it is important to recognize limitations of acute slices and distinct advantages of hippocampal slice cultures. Acute brain slices cannot reveal subtle changes in immune signaling since preparing the slices alone triggers: pro-inflammatory changes that last days, epileptiform behavior due to high levels of oxygen tension needed to vitalize the slices, and irreversible cell injury at anoxic slice centers. In contrast, we examine immune signaling in mature hippocampal slice cultures since the cultures closely parallel their in vivo counterpart with mature trisynaptic function; show quiescent astrocytes, microglia, and cytokine levels; and SD is easily induced in an unanesthetized preparation. Furthermore, the slices are long-lived and SD can be induced on consecutive days without injury, making this preparation the sole means to-date capable of modeling the neuroimmune consequences of chronic SD, and thus perhaps chronic migraine. We use electrophysiological techniques and non-invasive imaging to measure neuronal cell and circuit functions coincident with SD. Neural immune gene expression variables are measured with qPCR screening, qPCR arrays, and, importantly, use of cDNA preamplification for detection of ultra-low level targets such as interferon-gamma using whole, regional, or specific cell enhanced (via laser dissection microscopy) sampling. Cytokine cascade signaling is further assessed with multiplexed phosphoprotein related targets with gene expression and phosphoprotein changes confirmed via cell-specific immunostaining. Pharmacological and siRNA strategies are used to mimic and modulate SD immune signaling.

Pharmacological intervention studies using mouse models of the inflammatory bowel diseases: translating preclinical data into new drug therapies

Most therapeutic agents used in clinical practice today were originally developed and tested in animal models so that drug toxicity and safety, dose-responses, and efficacy could be determined. Retrospective analyses of preclinical intervention studies using animal models of different diseases demonstrate that only a small percentage of the interventions reporting promising effects translate to clinical efficacy. The failure to translate therapeutic efficacy from bench to bedside may be due, in part, to shortcomings in the design of the clinical studies; however, it is becoming clear that much of the problem resides within the preclinical studies. One potential strategy for improving our ability to identify new therapeutics that may have a reasonable chance of success in clinical trials is to identify the most immunologically-relevant mouse models of IBD and pharmacologic strategies that most closely mimic the clinical situation. This review presents a critical evaluation of the different mouse models and pharmacological approaches that may be used in intervention studies as well as discuss emerging issues related to study design and data interpretation of preclinical studies.

Tumor-infiltrating immune cells and prognosis: the potential link between conventional cancer therapy and immunity

Numerous studies have now documented a link between the immune infiltrate in several human carcinoma types and prognosis and response to therapy. The most comprehensive of these studies were in colorectal cancer with similar conclusions by numerous groups. Analyses of immune infiltrate of several other carcinoma types also showed general correlations between immune infiltrate and prognosis, but with some conflicting results. This review will attempt to summarize the current state of this field and point out what factors may be responsible for some of the conflicting findings. Nonetheless, the breadth of reports drawing similar conclusions for some cancer cell types leads one to more seriously consider the link between immune cell infiltrate and tumor prognosis and/or response to therapy, and the potential for combining conventional cancer therapy with active immunotherapy employing therapeutic cancer vaccines.

Role of the gut-associated and secondary lymphoid tissue in the induction of chronic colitis

BACKGROUND

It is well known that enteric bacterial antigens drive the development of chronic colitis in a variety of different mouse models of the inflammatory bowel diseases (IBD). The objective of this study was to evaluate the role of gut-associated lymphoid tissue (GALT; Peyer's patches, isolated lymphoid follicles), mesenteric lymph nodes (MLNs) and spleen in the pathogenesis of chronic colitis in mice.

METHODS

Surgical as well as genetic approaches were used to generate lymphopenic mice devoid of one or more of these lymphoid tissues. For the first series of studies, we subjected recombinase activating gene-1-deficient mice (RAG(-/-) ) to sham surgery (Sham), mesenteric lymphadenectomy (MLNx), splenectomy (Splx) or both (MLNx/Splx). In a second series of studies we intercrossed lymphotoxinβ-deficient (LTβ(-/-) ) mice with RAG(-/-) animals to generate LTβ(-/-) x RAG(-/-) offspring that were anticipated to contain functional MLNs but be devoid of GALT and most peripheral lymph nodes. Flow purified naïve (CD4(+) CD45RB(high) ) T-cells were adoptively transferred into the different groups of RAG(-/-) recipients to induce chronic colitis.

RESULTS

We found that at 3-5 wks following T-cell transfer, all four of the surgically-manipulated RAG(-/-) groups (Sham, MLNx, Splx and MLNx/Splx) developed chronic colitis that was similar in onset and severity. Flow cytometric analysis revealed no differences among the different groups with respect to surface expression of different gut-homing markers nor were there any differences noted in IFN-γ and IL-17 generation by mononuclear cells isolated among these surgically-manipulated mice. Although we anticipated that LTβ(-/-) x RAG(-/-) mice would contain functional MLNs but be devoid of GALT and peripheral lymph nodes (PLNs), we found that LTβ(-/-) x RAG(-/-) mice were in fact devoid of MLNs as well as GALT and PLNs. Adoptive transfer of CD45RB(high) T-cells into LTβ(-/-) x RAG(-/-) mice or their littermate controls (LTβ(+/+) x RAG(-/-) ) induced rapid and severe colitis in both groups.

CONCLUSIONS

Taken together, our data demonstrate that: a) neither the GALT, MLNs nor PLNs are required for induction of chronic gut inflammation in this model of IBD and b) T-and/or B-cells may be required for the development of MLNs in LTβ(-/-) mice.

Designing customized cell signalling circuits

Living cells have evolved a broad array of complex signalling responses, which enables them to survive diverse environmental challenges and execute specific physiological functions. Our increasingly sophisticated understanding of the molecular mechanisms of cell signalling networks in eukaryotes has revealed a remarkably modular organization and synthetic biologists are exploring how this can be exploited to engineer cells with novel signalling behaviours. This approach is beginning to reveal the logic of how cells might evolve innovative new functions and moves us towards the exciting possibility of engineering custom cells with precise sensing-response functions that could be useful in medicine and biotechnology.

Select phytochemicals suppress human T-lymphocytes and mouse splenocytes suggesting their use in autoimmunity and transplantation

We have considered a novel "rational" gene targeting approach for treating pathologies whose genetic bases are defined using select phytochemicals. We reason that one such potential application of this approach would be conditions requiring immunosuppression such as autoimmune disease and transplantation, where the genetic target is clearly defined; i.e., interleukin-2 and associated T-cell activation. Therefore, we hypothesized that select phytochemicals can suppress T-lymphocyte proliferation both in vitro and in vivo. The immunosuppressive effects of berry extract, curcumin, quercetin, sulforaphane, epigallocatechin gallate (EGCG), resveratrol, alpha-tocopherol, vitamin C and sucrose were tested on anti-CD3 plus anti-CD28-activated primary human T-lymphocytes in culture. Curcumin, sulforaphane, quercetin, berry extract and EGCG all significantly inhibited T-cell proliferation, and this effect was not due to toxicity. IL-2 production was also reduced by these agents, implicating this important T-cell cytokine in proliferation suppression. Except for berry extract, these same agents also inhibited mouse splenic T-cell proliferation and IL-2 production. Subsequent in vivo studies revealed that quercetin (but not sulforaphane) modestly suppressed mouse splenocyte proliferation following supplementation of BALB/c mice diets. This effect was especially prominent if corrected for the loss of supplement "recall" as observed in cultured T-cells. These results suggest the potential use of these select phytochemicals for treating autoimmune and transplant patients, and support our strategy of using select phytochemicals to treat genetically-defined pathologies, an approach that we believe is simple, healthy, and cost-effective.

Age-associated T-cell Clonal Expansions (TCE) in vivo—Implications for Pathogen Resistance

Age-related T-cell clonal expansions (TCE) are an incompletely understood disturbance in T-cell homeostasis found frequently in old humans and experimental animals. These accumulations of CD8 T-cells have the potential to distort T-cell population balance and reduce T-cell repertoire diversity above and beyond the changes seen in the aging of T-cell pool in the absence of TCE. This chapter discusses our current knowledge of the role of these expansions in health and disease, with a special focus on their influence upon immune defense against infectious diseases.

Antagonistic roles of CD4+ and CD8+ T-cells in 7,12-dimethylbenz(a)anthracene cutaneous carcinogenesis

The role that cell-mediated immune responses play during cutaneous carcinogenesis has received little attention. In this study, we evaluated the contribution of CD4(+) and CD8(+) T cells in C3H/HeN mice that were subjected to a two-stage 7,12-dimethylbenz(a)anthracene (DMBA) initiation, 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion skin carcinogenesis protocol. In CD8 knockout (CD8(-/-)) mice, allergic contact hypersensitivity to DMBA was reduced compared with wild-type (WT) C3H/HeN mice. On the other hand, CD4 knockout (CD4(-/-)) mice developed an exaggerated contact hypersensitivity response. CD4(+) T cells from DMBA contact-sensitized mice preferentially produced interleukin 4 (IL-4), IL-10, and IL-17; CD8(+) T cells, on the other hand, secreted IFN-gamma. When CD4(-/-), CD8(-/-), and WT mice were subjected to a standard two-stage DMBA/TPA cutaneous carcinogenesis protocol, the percentage of mice with tumors was much greater (P < 0.001) in CD8(-/-) mice than in WT mice. In contrast, the percentage of tumors was significantly less (P < 0.001) in CD4(-/-) mice than in WT mice. Similar results were obtained when the data were evaluated as the number of tumors per mouse. These findings indicate that (a) CD8(+) T cells are the predominant effector cells in allergic contact hypersensitivity to DMBA and that CD4(+) T cells have an inhibitory role and (b) the development of CD8(+) T cells plays a protective role in skin tumor development whereas CD4(+) T cells have the opposite effect. Manipulation of T-cell subpopulations that are induced by carcinogenic chemicals, like DMBA, could be a means of preventing skin cancers caused by these agents.

Combined immunization with adjuvant molecules poly(I:C) and anti-CD40 plus a tumor antigen has potent prophylactic and therapeutic antitumor effects

The low immunogenicity of malignant cells is one of the causes responsible for the lack of antitumor immune responses. Thus, development of new therapeutic strategies aimed at enhancing presentation of tumor antigens to T cells is a main goal of cancer immunotherapy. With this aim, we studied the efficacy of administering adjuvants poly(I:C) and agonistic anti-CD40 antibody plus a tumor antigen. Joint intravenous immunization with these adjuvants and a model tumor antigen (ovalbumin) was able to synergistically induce potent and long lasting antitumor T-cell responses. These responses protected against challenge with E.G7-OVA tumor cells in prophylactic short- and long-term vaccination. In a therapeutic setting, repeated intratumor administration of adjuvants plus antigen was able to reject established tumors in all treated animals, leading in some cases to the rejection of both locally treated and untreated tumors. Antitumor immune responses induced by these protocols were mediated not only by T-cells but also by NK cells. In conclusion, combined administration of adjuvants poly(I:C) and anti-CD40 plus a tumor antigen is an efficient strategy for prophylactic and therapeutic antitumor vaccination.

Intrapatient dose escalation of anti-CTLA-4 antibody in patients with metastatic melanoma

We previously reported our experience in treating 56 patients with metastatic melanoma using a human anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) antibody. Durable tumor regressions were seen that correlated with the induction of autoimmune toxicities. In this study, we treated 46 additional patients using an intrapatient dose escalation schema to test whether higher doses of anti-CTLA-4 antibody would induce increased autoimmunity and concomitant tumor regression. Twenty-three patients started anti-CTLA-4 antibody administration at 3 mg/kg and 23 patients started treatment at 5 mg/kg, receiving doses every 3 weeks. Patients were dose-escalated every other dose to a maximum of 9 mg/kg or until objective clinical responses or grade III/IV autoimmune toxicity were seen. Escalating doses of antibody resulted in proportionally higher plasma concentrations. Sixteen patients (35%) experienced a grade III/IV autoimmune toxicity. Five patients (11%) achieved an objective clinical response. Two of the responses are ongoing at 13 and 16 months, respectively. Flow cytometric analysis of peripheral blood revealed significant increases in both T-cell surface markers of activation and memory phenotype. Thus, higher serum levels and prolonged administration of anti-CTLA-4 antibody resulted in a trend toward a greater incidence of grade III/IV autoimmune toxicity than previously reported, but did not seem to increase objective response rates.

Off balance: T-cells in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides

There is substantial evidence that T-cells are off balance in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides. Genetic risk factors may influence shaping of the TCR repertoire and regulatory control of T-cells in predisposed individuals. T-cells are found in inflammatory lesions. Vigorous Th1-type responses are seen in Wegener's granulomatosis and microscopic angiitis, whereas a Th2-type response predominates in Churg-Strauss syndrome. Oligoclonality and shortened telomers indicate antigen-driven clonal expansion and replicative senescence of T-cells in ANCA-associated vasculitides. Potent CD28(-) Th1-type cells displaying an effector-memory/late differentiated, senescent phenotype are expanded in peripheral blood and are found in granulomatous lesions in Wegener's granulomatosis. Differences in proliferative peripheral blood T-cell responses to the autoantigens proteinase 3 (PR3)- and myeloperoxidase (MPO) have not consistently been detected between patients with ANCA-associated vasculitides and healthy controls in vitro. To recognize an autoantigen, break tolerance, and maintain autoimmune disease T- and B-cells require particular triggers and lymphoid structures. There is preliminary evidence of lymphoid-like structures and possible maturation of autoreactive PR3-ANCA-specific B-cells in granulomatous lesions in Wegener's granulomatosis. Alteration of the T-cell response and anomalous autoantigen-presentation in lymphoid-structures could facilitate development of autoimmune disease in ANCA-associated vasculitides.

The detection of mature T- and B-cells during development of the lymphoid tissues of the tammar wallaby (Macropus eugenii)

The distribution of T- and B-cells in the developing lymphoid and immunohaematopoietic tissues of the tammar wallaby were investigated using antibodies to the mature cell surface markers, CD3, CD5 and CD79b. In the thymus, CD3- and CD5-positive T-cells were first observed at day 12 postpartum whilst rare B-cells were first detected at day 23. Both T- and B-lymphocytes were first stained on day 21 postpartum in the spleen and day 24 in lymph nodes. In one sample from a 7-day-old animal, rare CD79b-positive (CD79b+) lymphocytes were observed in the gut-associated lymphoid tissues. However, CD3+ cells were not apparent until day 12 and CD5+ cells were not detected until day 74 postpartum. No lymphocytes were detected in liver or bone marrow samples and no bronchus-associated lymphoid tissues were observed. The pattern of development and the distribution of T- and B-cells in the lymphoid and immunohaematopoietic tissues were similar to those observed in eutherian mammals and in limited studies of other metatherians. However, the detection of apparently mature T- and B-cells in the thymus and gut-associated lymphoid tissues (GALT) at the same postnatal age highlights the need for a more substantial study of the development of GALT. This is, at present, limited by availability of marsupial-specific antibodies.

Essential role for caspase 8 in T-cell homeostasis and T-cell-mediated immunity

Defects in death receptor-mediated apoptosis have been linked to cancer and autoimmune disease in humans. The in vivo role of caspase 8, a component of this pathway, has eluded analysis in postnatal tissues because of the lack of an appropriate animal model. Targeted disruption of caspase 8 is lethal in utero. We generated mice with a targeted caspase 8 mutation that is restricted to the T-cell lineage. Despite normal thymocyte development in the absence of caspase 8, we observed a marked decrease in the number of peripheral T-cells and impaired T-cell response ex vivo to activation stimuli. caspase 8 ablation protected thymocytes and activated T-cells from CD95 ligand but not anti-CD3-induced apoptosis, or apoptosis activated by agents that are known to act through the mitochondria. caspase 8 mutant mice were unable to mount an immune response to viral infection, indicating that caspase 8 deletion in T-cells leads to immunodeficiency. These findings identify an essential, cell-stage-specific role for caspase 8 in T-cell homeostasis and T-cell-mediated immunity. This is consistent with the recent identification of caspase 8 mutations in human immunodeficiency.

Specific T-cell immunity against Ki-ras peptides in patients with pancreatic and colorectal cancers

Mutations of codon 12 in the Ki-ras gene are frequently found in pancreatic and colorectal cancers. It has been demonstrated that human T-cells have the potential to recognise tumours expressing mutated ras-derived peptides. However, it remains unclear whether T-cells from a given individual can recognise the mutant peptides, which are expressed in that individual's tumour tissues. Mutations of the Ki-ras oncogene were analysed by the mutant-allele-specific amplification (MASA) method in pancreatic and colorectal tumour tissues, and T-cell responses against mutated Ki-ras-derived peptides were measured by [(3)H]thymidine incorporation and IFN-gamma production assays. Specific T-cell responses against Ki-ras-products were found in cancer patients, whereas no immune response was observed in normal individuals (P<0.01). Six of the eight pancreatic cancer patients (75%) and nine of 26 colorectal cancer patients (35%) had T-cell responses to mutated Ki-ras-derived-peptides. T-cell response in a given individual cannot recognise the same mutated ras peptide, which is expressed in that individual's tumour tissues. However, pancreatic and colorectal cancer patients have T-cell immunity against Ki-ras-peptides, and this provides potential target for cancer immunotherapy.

LPS-stimulated human gingival fibroblasts inhibit the differentiation of monocytes into osteoclasts through the production of osteoprotegerin

Periodontitis is an inflammatory bone disease caused by Gram-negative anaerobic bacteria, but the precise mechanism of bone destruction remains unknown. Activated T lymphocytes secrete receptor activator of NF-kappaB ligand (RANKL) and support the differentiation of monocytes into mature osteoclasts. The purpose of this study was to examine the expression of RANKL and its inhibitor, osteoprotegerin (OPG), in inflamed gingival tissue and to clarify the role of human gingival fibroblasts (HGFs) in osteoclastogenesis regulated by RANKL. HGFs and gingival mononuclear cells (GMCs) were obtained from chronic periodontitis patients during routine periodontal surgery. Expression of OPG and RANKL mRNA in gingival tissue and HGFs was examined with RT-PCR. OPG production was measured using ELISA. Expression of RANKL, CD4, CD8 and CD69 on GMCs was determined by flow-cytometry using RANK-Fc fusion protein and the respective monoclonal antibodies. Osteoclastogenesis by RANKL was assayed by counting the number of tartarate-resistant acid phosphatase (TRAP)-positive cells after culturing human peripheral blood monocytes with recombinant human RANKL and macrophage-colony stimulating factor (M-CSF) for 10 days. OPG and RANKL mRNA were expressed in 80% (16/20) and 25% (5/20) of periodontitis lesions, respectively. OPG, but not RANKL, mRNA was expressed within HGFs. OPG mRNA expression and production by HGFs was augmented by LPS stimulation. All GMC samples expressed CD69, and two of five GMC samples expressed RANKL. The culture supernatant of LPS-stimulated gingival fibroblasts significantly reduced the number of TRAP positive cells generated by culturing monocytes with RANKL and M-CSF. The present study suggests that LPS-stimulated HGFs inhibit monocyte differentiation into osteoclasts through the production of OPG.

T-cells in the cerebrospinal fluid express a similar repertoire of inflammatory chemokine receptors in the absence or presence of CNS inflammation: implications for CNS trafficking

It is believed that chemokines and their receptors are involved in trafficking of T-cells to the central nervous system (CNS). The aim of the current study was to define the expression on cerebrospinal fluid (CSF) T-cells of six chemokine receptors associated with trafficking to sites of inflammation. Flow cytometry was used to detect chemokine receptor expression. We observed that CD3+T-cells in the CSF express a restricted array of inflammatory chemokine receptors, specifically CXCR3, CCR5 and CCR6, but little CCR1-3. This repertoire was independent of the presence of CNS inflammation, since comparable findings were obtained in patients with multiple sclerosis (MS) and individuals with non-inflammatory neurological diseases. The enrichment of CCR5+T-cells in the CSF could largely be explained by higher frequency of CD4+/CD45RO+T-cells in this compartment. In contrast, CD4+/CD45RO+T-cells expressing CXCR3 were significantly enriched in CSF as compared with blood. Similar levels of CCR6+/CD3+T-cells were observed in blood and CSF, while levels of CCR2+/CD3+T-cells were lower in CSF than in blood. The CSF was virtually devoid of CCR5+/CXCR3- T-cells, suggesting that the expression of CCR5 alone is not sufficient for the trafficking of CD3+T-cells to the CSF. We hypothesize that CXCR3 is the principal inflammatory chemokine receptor involved in intrathecal accumulation of T-cells in MS. Through interactions with its ligands, CXCR3 is proposed to mediate retention of T-cells in the inflamed CNS.

Evidence for selective effects on adhesion to extracellular matrix components via SSTR2 and/or 3

We have examined normal T-cells and T-cell lines with respect to expression of various somatostatin receptor subtypes (SSTR1--5) using RT-PCR and PCR. To evaluate the function of these receptors we have further studied the effects of subtype specific signalling on T-cell adhesion using somatostatin analogs specific for various receptors as probes. Human T-lymphocytes showed SSTR expression related to activation and stage of differentiation. Normal T-cells (peripheral blood, T-cell clone) and T-leukaemia cell lines expressed SSTR2, SSTR3 and SSTR4. Normal T-cells expressed SSTR1 and SSTR5 while T-leukaemia lines did not. SSTR5 was selectively expressed in activated normal T-cells. T-lymphocytes produced no somatostatin themselves. Somatostatin and somatostatin analogs specific for SSTR2 and/or SSTR3 enhanced adhesion of T-cells to fibronectin (FN), and to a certain extent, also to collagen type IV (CIV) and laminin (LAM). T-lymphocytes express multiple SSTR and somatostatin may therefore regulate lymphocyte functions via distinct receptor subtypes as shown here for adhesion to extracellular matrix components (ECM) via SSTR2 and SSTR3. SSTR expression also distinguishes normal and leukaemic T-cells. Our findings suggest that SSTR subtypes may be useful targets for therapy during inflammatory diseases and malignancies affecting lymphocytes.

MIP-1alpha, MCP-1, GM-CSF, and TNF-alpha control the immune cell response that mediates rapid phagocytosis of myelin from the adult mouse spinal cord

The slow immune response in the adult mammalian CNS results in slow myelin phagocytosis along degenerating white matter after injury. This has important consequences for axon regeneration because of the presence of axon growth inhibitors in myelin. In addition, abnormal immune cell responses in the CNS lead to demyelinating disease. Lysophosphatidylcholine (LPC) can induce an inflammatory response in the CNS, producing rapid demyelination without much damage to adjacent cells. In this study, we searched for the molecular switches that turn on this immune cell response. Using reverse transcription PCR analysis, we show that mRNA expression of macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1 (MCP-1), granulocyte macrophage-colony stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha) in the spinal cord is rapidly and transiently upregulated after intraspinal injection of LPC. Neutralizing these signaling molecules with function-blocking antibodies suppresses recruitment of T-cells, neutrophils, and monocytes into the spinal cord, as well as significantly reduces the number of phagocytic macrophages and the demyelination induced by LPC. These findings will have important implications for CNS regeneration and demyelinating disease.

Vaccination for neuroprotection in the mouse optic nerve: implications for optic neuropathies

T-cell autoimmunity to myelin basic protein was recently shown to be neuroprotective in injured rat optic nerves. In the present study, using the mouse optic nerve, we examined whether active immunization rather than passive transfer of T-cells can be beneficial in protecting retinal ganglion cells (RGCs) from post-traumatic death. Before severe crush injury of the optic nerve, SJL/J and C3H.SW mice were actively immunized with encephalitogenic or nonencephalitogenic peptides of proteolipid protein (PLP) or myelin oligodendrocyte glycoprotein (MOG), respectively. At different times after the injury, the numbers of surviving RGCs in both strains immunized with the nonencephalitogenic peptides pPLP 190-209 or pMOG 1-22 were significantly higher than in injured controls treated with the non-self-antigen ovalbumin or with a peptide derived from beta-amyloid, a non-myelin-associated protein. Immunization with the encephalitogenic myelin peptide pPLP 139-151 was beneficial only when the disease it induced, experimental autoimmune encephalomyelitis, was mild. The results of this study show that survival of RGCs after axonal injury can be enhanced by vaccination with an appropriate self-antigen. Furthermore, the use of nonencephalitogenic myelin peptides for immunization apparently allows neuroprotection without incurring the risk of an autoimmune disease. Application of these findings might lead to a promising new approach for treating optic neuropathies such as glaucoma.

The distinct role of CD4+ and CD8+ T-cells during the anti-tumour effects of targeted superantigens

To target T-cells to the tumour area we created a recombinant protein of the bacterial superantigen (SAg) Staphylococcal enterotoxin A (SEA) and the Fab-fragment of a tumour-reactive antibody. This antibody-targeted SAg immunotherapy therapy has been shown to be highly efficient, eliminating > 95% of the pulmonary metastasis in mice carrying established melanoma micrometastases. Earlier studies demonstrated that elimination of the C215-expressing B16-melanoma lung metastasis was dependent on interferon (IFN)-gamma release and expression of perforin. In the present study, therapeutic effector functions were analysed both locally at the tumour site and systemically in the spleen. In order to elucidate the role of each T-cell subset during Fab-SEA therapy, CD4 knock-out (KO) and CD8 KO mice were used. Tumour size reduction was statistically significant in Fab-SEA-based tumour therapy in both types of T-cell-deficient mice compared to wild-type mice. CD4 KO mice displayed a drastic reduction in the number of tumour-infiltrating macrophages and CD8+ T-cells. Therapy-induced accumulation of perforin-containing cells at the tumour site was significantly impaired in CD8 KO mice, and marginally in CD4 KO mice. Moreover, CD4 KO mice failed to produce substantial amounts of the tumour suppressive cytokine IFN-gamma. This is in sharp contrast to normal mice where a massive local release was recorded. CD8 KO mice displayed a spontaneous production of interleukin (IL)-4 and IL-10 locally in the tumour. Neither normal nor CD4 KO mice produced detectable levels of these Th-2-associated cytokines. The high level of IL-10 was demonstrated to inhibit Fab-SEA tumour therapy, since the therapeutic efficacy was significantly higher in IL-10 KO mice. These results illustrate the importance of a finely tuned cellular collaboration to regulate the various phases of an efficient anti-tumour immune response.

Identification of women with early breast cancer by analysis of p43-positive lymphocytes

Regular screening mammographies and increasing knowledge of high-risk groups have resulted in an improvement in the rate of detection of smaller malignant lesions. However, uncertain minimal mammographic features frequently require further costly and often uncomfortable investigation, including repeat radiological controls or surgical procedures, before cancerous lesions can be identified. Placental isoferritin (p43), a protein with immunosuppressive effects, has been detected on the surface of lymphocytes taken from peripheral blood in patients with breast cancer. In this study we evaluated the sensitivity and specificity of the expression of p43-positive lymphocytes as a marker in early stage breast cancer and also investigated its expression on T-cell subpopulations. The presence of p43-positive lymphocytes was investigated using the monoclonal antibody CM-H-9 and flow cytometry in 76 women with controversial, non-palpable mammographic findings who were undergoing surgical biopsy. Patients with early breast cancer (n = 48) had significantly higher p43-positive cell values (median 3.83%, range 0.98-19.4) than patients with benign lumps (n = 28, median 1.43%, range 0.17-3.7) or controls (n = 22, median 1.3%, range 0.4-1.87) (P < 0.0001). At a cut-off level of 2% p43-positive cells a sensitivity of 91.7% and a specificity of 89.3% for detection of breast cancer could be reached. While the median ratio of total CD4+/CD8+ cells was 2.6, a ratio of 1.3 was found for the p43-positive subpopulation (P < 0.001), thus indicating a significant link between p43 and CD8+ cells. The determination of p43-positive lymphocytes in peripheral blood could serve as an additional diagnostic tool in patients with controversial mammographic findings and could also reduce the need for cost-intensive and often uncomfortable management of these patients.

T cell mediated induction of bronchial hyperreactivity

Inadequate reactions of the immune system, i.e. allergic or hypersensitivity reactions, can lead to lung tissue injury. We investigated the relationship of type IV hypersensitivity, as an example of IgE independent hypersensitivity, with the induction of airway hyperreactivity. After antigen challenge (picrylsulphonic acid (PSA] in picrylchloride (PCl) sensitized mice, peribronchial and perivascular accumulation of mononuclear cells was found that was maximal 48 h after challenge. At several time points after challenge, changes in smooth muscle tone of mouse isolated tracheas were measured isometrically. In sensitized mice the response to carbachol was increased, reaching a maximum 48 h after challenge. This hyperreactivity was not found in athymic (nude) mice. We concluded from these data that airway hyperreactivity can be immunologically induced other than by IgE.

Antibody-dependent cell-mediated cytotoxicity in sheep

The ability of sheep leukocytes to mediate antibody — dependent cell-mediated cytotoxicity (ADCC) and that of sheep serum IgG₁ and IgG₂ to induce ADCC were investigated. Partial characterization of effector cells was attempted. These investigations revealed that ADCC occurs in sneep. With chicken erythrocytes (CRBC) as the target cells, polymorphonu-cleated cells (PMN), and monocytes, were the most effective leukocytes. Ovine peripheral blood lymphocytes (PBL) also mediated ADCC, and within the PBL population, T-cells were capable of mediating ADCC. The T-cells were obtained by nylon wool fractionation and selective agglutination by peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA). Both nylon wool adherent and non-adherent fractions were active in ADCC, although the former were more active, implying heterogeneity in nylon wool adherence among ovine K-cells. Depletion of B (SIg⁺) cells did not affect ADCC activity of the remaining cells. Depletion of Fc⁺ cells markedly reduced cytotoxic activity of PBL. Both sheep IgG₁ and IgG₂ anti-CRBC immunoglobulins were able to induce ADCC.

Genetic variation of an esterase system in sera of dogs

Sera from 7 dog families comprising 20 parents with 48 offspring and 70 unrelated dogs of various breeds have been studied with regard to polymorphism of esterases. Isoelectric focusing in Polyacrylamide gels of pH ranges 4.2–4.9 and 4–6 revealed great variation of phenotypes. These appeared as complex band patterns always with more than 8 zones. Treatment with an organophosphorous compound and ions of heavy metals strongly indicate that the majority of zones represent arylesterase (ArE) whereas some of the bands are Cholinesterase. ArE phenotypes in families together with the appearances of band patterns in the 70 unrelated dogs are in agreement with a genetic theory of 1 locus with 5 codominant alleles. These have temporarily been named ArE^D, ArE^H, ArE^K, ArE^Q and ArE^W with ArED being the most anodal phenotype and the others in logical order. The ArE^K and ArE^Q were most common but phenotypes representing the ArE^D, ArE^H and ArE^W alleles were each observed in several animals.

Regulation of lymphocyte responses in vitro: potentiation and inhibition of rat lymphocyte responses to antigen and mitogens by cytochalasin B

Cytochalasin B, at concentration between 0.02 and 0.2 mug/ml, was slightly stimulatory to lymph-node cells from normal rats and greatly potentiated their response to phytohemagglutinin and low concentrations of concanavalin A (mitogens for thymus-derived lymphocytes); it also potentiated the response of thymocytes to phytohemagglutinin. The response of lymphnode cells to lipopolysaccharide endotoxin (a mitogen for thymus-independent lymphocytes) was also enhanced, but only at concentrations in the usual inhibitory range, possibly by inhibition of a "suppressor T-cell" response. Sensitized lymphocytes responding to antigen were not stimulated at all, except at a very high cell density, where inhibition of a "suppressor cell" response was also considered likely. At concentrations of 5-10 mug/ml or higher, cytochalasin B inhibited all responses tested.