Phase I trial of viral vector based personalized vaccination elicits robust neoantigen specific antitumor T cell responses.

PURPOSE: Personalized vaccines targeting multiple neoantigens (nAgs) are a promising strategy for eliciting a diversified antitumor T cell response to overcome tumor heterogeneity. NOUS-PEV is a vector based personalized vaccine, expressing 60 nAgs and consists of priming with a non-human Great Ape Adenoviral vector (GAd20) followed by boosts with Modified Vaccinia Ankara (MVA). Here, we report data of a phase Ib trial of NOUS-PEV in combination with pembrolizumab in treatment naïve metastatic melanoma patients (NCT04990479). EXPERIMENTAL DESIGN: The feasibility of this approach was demonstrated by producing, releasing and administering to six patients 11 out of 12 vaccines within 8 weeks from biopsy collection to GAd20 administration. RESULTS: The regimen was safe, with no treatment-related serious adverse events observed and mild vaccine-related reactions. Vaccine immunogenicity was demonstrated in all evaluable patients receiving the prime/boost regimen, with detection of robust neoantigen specific immune responses to multiple neoantigens comprising both CD4 and CD8 T cells. Expansion and diversification of vaccine-induced TCR clonotypes was observed in the post-treatment biopsies of patients with clinical response providing evidence of tumor infiltration by vaccine-induced neoantigen-specific T cell. CONCLUSIONS: These findings indicate the ability of NOUS-PEV to amplify and broaden the repertoire of tumor reactive T cells to empower a diverse, potent and durable antitumor immune response. Finally, a gene signature indicative for reduced presence of activated T cells together with very poor expression of the antigen processing machinery (APM) genes has been identified in pre-treatment biopsies as a potential biomarker of resistance to the treatment.

Insight into immune profile associated with vitiligo onset and anti-tumoral response in melanoma patients receiving anti-PD-1 immunotherapy.

Introduction: Immunotherapy with checkpoint inhibitors is an efficient treatment for metastatic melanoma. Development of vitiligo upon immunotherapy represents a specific immune-related adverse event (irAE) diagnosed in 15% of patients and associated with a positive clinical response. Therefore, a detailed characterization of immune cells during vitiligo onset in melanoma patients would give insight into the immune mechanisms mediating both the irAE and the anti-tumor response. Methods: To better understand these aspects, we analyzed T cell subsets from peripheral blood of metastatic melanoma patients undergoing treatment with anti-programmed cell death protein (PD)-1 antibodies. To deeply characterize the antitumoral T cell response concomitant to vitiligo onset, we analyzed T cell content in skin biopsies collected from melanoma patients who developed vitiligo. Moreover, to further characterize T cells in vitiligo skin lesion of melanoma patients, we sequenced T cell receptor (TCR) of cells derived from biopsies of vitiligo and primary melanoma of the same patient. Results and discussion: Stratification of patients for developing or not developing vitiligo during anti-PD-1 therapy revealed an association between blood reduction of CD8-mucosal associated invariant T (MAIT), T helper (h) 17, natural killer (NK) CD56bright, and T regulatory (T-reg) cells and vitiligo onset. Consistently with the observed blood reduction of Th17 cells in melanoma patients developing vitiligo during immunotherapy, we found high amount of IL-17A expressing cells in the vitiligo skin biopsy, suggesting a possible migration of Th17 cells from the blood into the autoimmune lesion. Interestingly, except for a few cases, we found different TCR sequences between vitiligo and primary melanoma lesions. In contrast, shared TCR sequences were identified between vitiligo and metastatic tissues of the same patient. These data indicate that T cell response against normal melanocytes, which is involved in vitiligo onset, is not typically mediated by reactivation of specific T cell clones infiltrating primary melanoma but may be elicited by T cell clones targeting metastatic tissues. Altogether, our data indicate that anti-PD-1 therapy induces a de novo immune response, stimulated by the presence of metastatic cells, and composed of different T cell subtypes, which may trigger the development of vitiligo and the response against metastatic tumor.

Sex differences and predictors of completion of a 6-month exercise-based cardiac rehabilitation program in 1,536 people following stroke.

OBJECTIVE: To retrospectively examine sex-differences and predictors of completion in consecutively-referred patients to a 6-month exercise-based cardiac rehabilitation program (CRP) from 2006 to 2017. MATERIALS/METHODS: People with hemiplegic gait participated in stroke-adapted-CRP; otherwise, traditional-CRP. Reasons for non-completion were ascertained by interview. Regression-analyses were conducted to determine non-completion in all patients and women and men separately. RESULTS: There were 1536 patients (30.3% women), mean age 64.5 ± 12.5 with 23% initiating the stroke-adapted-CRP. Overall, 75.1% completed the CRP (87.3% stroke-adapted-CRP vs 71.5% traditional-CRP; p < .001). There was no difference in completion between women and men (74.5% vs 75.4%; p=0.7), or in attendance to pre-scheduled sessions (p=0.6) or reasons for non-completion (p > .05, all). The only sex difference in completion by age (decade) occurred in those <41 years (59% women vs 85% men; p=.02). Baseline predictors of non-completion among all patients included not being enrolled in the stroke-adapted-CRP, lower V̇O2peak, smoking, diabetes (prescribed insulin) and depression but not sex (p=.5) or age (p=.15). Unique predictors in women vs men were younger age, lower V̇O2peak, smoking, diabetes (prescribed insulin), depression, and cancer diagnoses. Unique to men was having >1 stroke and diabetes (any anti-diabetes medication). The strongest predictor of non-completion among all models was not being enrolled in stroke-adapted-CRP. CONCLUSIONS: While there were no sex-differences in adherence to the CRP, women and men have mostly unique predictors of non-completion. Younger women are at greatest risk for non-completion. Practitioners should provide sex-specific, tailored strategies for enhancing completion with a focus on younger women and offering a stroke-adapted-CRP with close attention to those with diabetes.

Inhibition of the PI3K/AKT/mTOR signaling promotes an M1 macrophage switch by repressing the ATF3-CXCL8 axis in Ewing sarcoma.

Ewing sarcomas are aggressive pediatric tumors of bone and soft tissues driven by in frame chromosomal translocations that yield fusion proteins guiding the oncogenic program. Promising alternative strategies to ameliorate current treatments involve inhibition of the PI3K/AKT/mTOR pathway. In this study, we identified the activating transcription factor 3 (ATF3) as an important mediator of the PI3K/AKT/mTOR pathway in Ewing sarcoma cells. ATF3 exerted its pro-tumoral activity through modulation of several chemokine-encoding genes, including CXCL8. The product of CXCL8, IL-8, acts as a pro-inflammatory chemokine critical for cancer progression and metastasis. We found that ATF3/IL-8 axis impacts macrophages populating the surrounding tumor microenvironment by promoting the M2 phenotype. Our study reveals valuable information on the PI3K/AKT/mTOR derived chemokine signaling in Ewing sarcoma cells: by promoting ATF3 and CXCL8 downregulation, inhibition of the PI3K/AKT/mTOR signaling promotes a proinflammatory response leading to upregulation of the protective anti-tumoral M1 macrophages.

Caspase-8 as a novel mediator linking Src kinase signaling to enhanced glioblastoma malignancy.

Caspase-8 is a cysteine protease that plays an essential role in apoptosis. Consistently with its canonical proapoptotic function, cancer cells may genetically or epigenetically downregulate its expression. Unexpectedly, Caspase-8 is often retained in cancer, suggesting the presence of alternative mechanisms that may be exploited by cancer cells to their own benefit. In this regard, we reported that Src tyrosine kinase, which is aberrantly activated in many tumors, promotes Caspase-8 phosphorylation on Tyrosine 380 (Y380) preventing its full activation. Here, we investigated the significance of Caspase-8 expression and of its phosphorylation on Y380 in glioblastoma, a brain tumor where both Caspase-8 expression and Src activity are often aberrantly upregulated. Transcriptomic analyses identified inflammatory response as a major target of Caspase-8, and in particular, NFκB signaling as one of the most affected pathways. More importantly, we could show that Src-dependent phosphorylation of Caspase-8 on Y380 drives the assembly of a multiprotein complex that triggers NFκB activation, thereby inducing the expression of inflammatory and pro-angiogenic factors. Remarkably, phosphorylation on Y380 sustains neoangiogenesis and resistance to radiotherapy. In summary, our work identifies a novel interplay between Src kinase and Caspase-8 that allows cancer cells to hijack Caspase-8 to sustain tumor growth.

Th17 and Th1 cells in systemic lupus erythematosus with focus on lupus nephritis.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by T cells imbalance. Indeed, a correlation between levels of Th17 cells and disease activity has been reported. Our work aimed to study the functional association of subpopulations of Th cells and SLE with (lupus nephritis, LN) or without (lupus erythematosus, LE) renal involvement in Tunisian patients through the detection of intracellular cytokines and surface marker expression. The IL23R and RORC mRNA expression levels were evaluated. The level of Th17 and Th1 cells was higher in LE and LN patients compared to healthy controls (HC) (p = 0.007 and p = 0.018, respectively), while Th1/17 cells were increased only in LN patients compared to HC (p = 0.011). However, no significant difference was described in the mRNA expression levels of RORC and IL-23R between SLE and HC. Our findings suggest that the Th1/Th17 differentiation mechanisms are altered in SLE and that this imbalance should have an important influence on the development and severity of the disease.

Assessment of T-cell Reactivity to the SARS-CoV-2 Omicron Variant by Immunized Individuals.

Importance: The emergence of the highly contagious Omicron variant of SARS-CoV-2 and the findings of a significantly reduced neutralizing potency of sera from individuals with previous SARS-CoV-2 infection or vaccination highlights the importance of studying cellular immunity to estimate the degree of immune protection to the new SARS-CoV-2 variant. Objective: To determine T-cell reactivity to the Omicron variant in individuals with established (natural and/or vaccine-induced) immunity to SARS-CoV-2. Design, Setting, and Participants: This was a cohort study conducted between December 20 and 21, 2021, at the Santa Lucia Foundation Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy, among health care worker and scientist volunteers. Lymphocytes from freshly drawn blood samples were isolated and immediately tested for reactivity to the spike protein of SARS-CoV-2. Main Outcomes and Measures: The main outcomes were the measurement of T-cell reactivity to the mutated regions of the spike protein of the Omicron BA.1 SARS-CoV-2 variant and the assessment of remaining T-cell immunity to the spike protein by stimulation with peptide libraries. Results: A total of 61 volunteers (mean (range) age, 41.62 (21-62) years; 38 women [62%]) with different vaccination and SARS-CoV-2 infection backgrounds were enrolled. The median (range) frequency of CD4+ T cells reactive to peptides covering the mutated regions in the Omicron variant was 0.039% (0%-2.356%), a decrease of 64% compared with the frequency of CD4+ cells specific for the same regions of the ancestral strain (0.109% [0%-2.376%]). Within CD8+ T cells, a median (range) of 0.02% (0%-0.689%) of cells recognized the mutated spike regions, while 0.039% (0%-3.57%) of cells were reactive to the equivalent unmutated regions, a reduction of 49%. However, overall reactivity to the peptide library of the full-length protein was largely maintained (estimated 87%). No significant differences in loss of immune recognition were identified between groups of participants with different vaccination or infection histories. Conclusions and Relevance: This cohort study of immunized adults in Italy found that despite the mutations in the spike protein, the SARS-CoV-2 Omicron variant was recognized by the cellular component of the immune system. It is reasonable to assume that protection from hospitalization and severe disease will be maintained.

Vitiligo-specific soluble biomarkers as early indicators of response to immune checkpoint inhibitors in metastatic melanoma patients.

Immunotherapy with checkpoint inhibitors (CPIs) strongly improved the outcome of metastatic melanoma patients. However, not all the patients respond to treatment and identification of prognostic biomarkers able to select responding patients is currently of outmost importance. Considering that development of vitiligo-like depigmentation in melanoma patients represents both an adverse event of CPIs and a favorable prognostic factor, we analyzed soluble biomarkers of vitiligo to validate them as early indicators of response to CPIs. Fifty-seven metastatic melanoma patients receiving CPIs were enrolled and divided according to the best overall response to treatment. Patient sera were evaluated at pre-treatment and after 1 and 3 months of therapy. We found that basal CD25 serum levels were higher in stable and responding patients and remained higher during the first 3 months of CPI therapy compared to non-responders. CXCL9 was absent in non-responding patients before therapy beginning. Moreover, an increase of CXCL9 levels was observed at 1 and 3 months of therapy for all patients, although higher CXCL9 amounts were present in stable and responding compared to non-responding patients. Variations in circulating immune cell subsets was also analyzed, revealing a reduced number of regulatory T lymphocytes in responding patients. Altogether, our data indicate that a pre-existing and maintained activation of the immune system could be an indication of response to CPI treatment in melanoma patients.

Systems analysis of human T helper17 cell differentiation uncovers distinct time-regulated transcriptional modules.

T helper (Th) 17 cells protect from infections and are pathogenic in autoimmunity. While human Th17 cell differentiation has been defined, the global and stepwise transcriptional changes accompanying this process remain uncharacterized. Herein, by performing transcriptome analysis of human Th17 cells, we uncovered three time-regulated modules: early, involving exclusively "signaling pathways" genes; late, characterized by response to infections; and persistent, involving effector immune functions. To assign them an inflammatory or regulatory potential, we compared Th17 cells differentiated in presence or absence of interleukin (IL)-1ß, respectively. Most inflammatory genes belong to the persistent module, whereas regulatory genes are lately or persistently induced. Among inflammatory genes, we identified the effector molecules IL17A, IL17F, IL26, IL6, interferon (IFN)G, IFNK, LTA, IL1A, platelet-derived growth factor (PDGF) A and the transcriptional regulators homeodomain-only protein homeobox (HOPX) and sex-determining-region-Y-box (SOX)2, whose expression was independently validated. This study provides an integrative representation of the stepwise human Th17 differentiation program and offers new perspectives toward therapeutic targeting of Th17-related autoimmune diseases.

Identification and Purification of Human Memory T Helper Cells from Peripheral Blood.

T helper (Th) cells are involved in various physiopathological systems, including response to infections, vaccination, cancer, and autoimmunity. The isolation of viable human Th cells is a procedure that allows a broad study of both phenotypical and functional features of each Th subset, and thus, it is necessary to study these cells in different contexts. In particular, the purification of human memory Th cells from peripheral blood is preparatory for further complex experiments on these cells, such as global transcriptional analysis, coculture assays, silencing experiments, and drug assays.Here, we describe the method for the identification and isolation of pure memory human Th1, Th2, Th17, Th1/17, and T regulatory cells, derived from peripheral blood mononuclear cells. Moreover, we show the purity of each purified Th subset, verified by the analysis of specific transcription factors.

MYC Upregulation Confers Resistance to Everolimus and Establishes Vulnerability to Cyclin-Dependent Kinase Inhibitors in Pancreatic Neuroendocrine Neoplasm Cells.

INTRODUCTION: Dysregulation of the mechanistic target of rapamycin complex 1 (mTORC1)-dependent pathways in pancreatic neuroendocrine neoplasms (PanNENs) underlies the introduction of the mTORC1 inhibitor everolimus as treatment of advanced progressive PanNENs. Although everolimus significantly increases progression-free survival, most patients acquire secondary resistance to the drug. This study aimed at identifying mechanisms involved in acquisition of resistance to everolimus. METHODS: BON-1 and everolimus-resistant (ER) BON-1 cells were used as in vitro system of sensitivity and acquired resistance. Transcriptome changes occurring in BON-1 and ER-BON-1 were investigated by RNA sequencing and validated by quantitative PCR analysis. RNA extracted from patients' biopsies was used to validate MYC upregulation. Drug screening and functional assays were performed using ER-BON-1 cells. Cell cycle progression was evaluated by FACS analysis. RESULTS: Our results show that MYC overexpression is a key event in the development of secondary resistance to everolimus in PanNEN cell lines and in metastatic lesions from neuroendocrine neoplasm patients. MYC knockdown restored ER-BON-1 sensitivity to everolimus. Pharmacological inhibition of MYC mediated by the cyclin-dependent kinase inhibitor dinaciclib strongly reduced viability of ER-BON-1. Dinaciclib synergized with everolimus and inhibited ER-BON-1 cell cycle progression. DISCUSSION: Our findings suggest that MYC upregulation drives the development of secondary resistance to everolimus in PanNENs and that its inhibition is an exploitable vulnerability. Indeed, our results indicate that combined treatments with cyclin-dependent kinase and mTOR inhibitors may counteract secondary resistance to everolimus in PanNENs and may pave the ground for new therapeutic regimens for these tumors.

The RNA-binding protein MEX3A is a prognostic factor and regulator of resistance to gemcitabine in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer. Most patients present with advanced disease at diagnosis, which only permits palliative chemotherapeutic treatments. RNA dysregulation is a hallmark of most human cancers, including PDAC. To test the impact of RNA processing dysregulation on PDAC pathology, we performed a bioinformatics analysis to identify RNA-binding proteins (RBPs) associated with prognosis. Among the 12 RBPs associated with progression-free survival, we focused on MEX3A because it was recently shown to mark an intestinal stem cell population that is refractory to chemotherapeutic treatments, a typical feature of PDAC. Increased expression of MEX3A was correlated with higher disease stage in PDAC patients and with tumor development in a mouse model of PDAC. Depletion of MEX3A in PDAC cells enhanced sensitivity to chemotherapeutic treatment with gemcitabine, whereas its expression was increased in PDAC cells selected upon chronic exposure to the drug. RNA-sequencing analyses highlighted hundreds of genes whose expression is sensitive to MEX3A expression, with significant enrichment in cell cycle genes. MEX3A binds to its target mRNAs, like cyclin-dependent kinase 6 (CDK6), and promotes their stability. Accordingly, knockdown of MEX3A caused a significant reduction in PDAC cell proliferation and in progression to the S phase of the cell cycle. These findings uncover a novel role for MEX3A in the acquisition and maintenance of chemoresistance by PDAC cells, suggesting that it may represent a novel therapeutic target for PDAC.

Interleukin-9 regulates macrophage activation in the progressive multiple sclerosis brain.

BACKGROUND: Multiple sclerosis (MS) is an immune-mediated, chronic inflammatory, and demyelinating disease of the central nervous system (CNS). Several cytokines are thought to be involved in the regulation of MS pathogenesis. We recently identified interleukin (IL)-9 as a cytokine reducing inflammation and protecting from neurodegeneration in relapsing-remitting MS patients. However, the expression of IL-9 in CNS, and the mechanisms underlying the effect of IL-9 on CNS infiltrating immune cells have never been investigated. METHODS: To address this question, we first analyzed the expression levels of IL-9 in post-mortem cerebrospinal fluid of MS patients and the in situ expression of IL-9 in post-mortem MS brain samples by immunohistochemistry. A complementary investigation focused on identifying which immune cells express IL-9 receptor (IL-9R) by flow cytometry, western blot, and immunohistochemistry. Finally, we explored the effect of IL-9 on IL-9-responsive cells, analyzing the induced signaling pathways and functional properties. RESULTS: We found that macrophages, microglia, and CD4 T lymphocytes were the cells expressing the highest levels of IL-9 in the MS brain. Of the immune cells circulating in the blood, monocytes/macrophages were the most responsive to IL-9. We validated the expression of IL-9R by macrophages/microglia in post-mortem brain sections of MS patients. IL-9 induced activation of signal transducer and activator of transcription (STAT)1, STAT3, and STAT5 and reduced the expression of activation markers, such as CD45, CD14, CD68, and CD11b in inflammatory macrophages stimulated in vitro with lipopolysaccharide and interferon (IFN)-γ. Similarly, in situ the number of activated CD68+ macrophages was significantly reduced in areas with high levels of IL-9. Moreover, in the same conditions, IL-9 increased the secretion of the anti-inflammatory cytokine, transforming growth factor (TGF)-ß. CONCLUSIONS: These results reveal a new cytokine expressed in the CNS, with a role in the context of MS. We have demonstrated that IL-9 and its receptor are both expressed in CNS. Moreover, we found that IL-9 decreases the activation state and promotes the anti-inflammatory properties of human macrophages. This mechanism may contribute to the beneficial effects of IL-9 that are observed in MS, and may be therapeutically potentiated by modulating IL-9 expression in MS.

Transcriptional Regulators of T Helper 17 Cell Differentiation in Health and Autoimmune Diseases.

T helper (Th) 17 cells are a subtype of CD4 T lymphocytes characterized by the expression of retinoic acid-receptor (RAR)-related orphan receptor (ROR)γt transcription factor, encoded by gene Rorc. These cells are implicated in the pathology of autoimmune inflammatory disorders as well as in the clearance of extracellular infections. The main function of Th17 cells is the production of cytokine called interleukin (IL)-17A. This review highlights recent advances in mechanisms regulating transcription of IL-17A. In particular, we described the lineage defining transcription factor RORγt and other factors that regulate transcription of Il17a or Rorc by interacting with RORγt or by binding their specific DNA regions, which may positively or negatively influence their expression. Moreover, we reported the eventual involvement of those factors in Th17-related diseases, such as multiple sclerosis, rheumatoid arthritis, psoriasis, and Crohn's disease, characterized by an exaggerated Th17 response. Finally, we discussed the potential new therapeutic approaches for Th17-related diseases targeting these transcription factors. The wide knowledge of transcriptional regulators of Th17 cells is crucial for the better understanding of the pathogenic role of these cells and for development of therapeutic strategies aimed at fighting Th17-related diseases.

Distinct Expression of Inflammatory Features in T Helper 17 Cells from Multiple Sclerosis Patients.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). T helper (Th) 17 lymphocytes play a role in the pathogenesis of MS. Indeed, Th17 cells are abundant in the cerebrospinal fluid and peripheral blood of MS patients and promote pathogenesis in the mouse model of MS. To gain insight into the function of Th17 cells in MS, we tested whether Th17 cells polarized from naïve CD4 T cells of healthy donors and MS patients display different features. To this end, we analysed several parameters that typify the Th17 profile during the differentiation process of naïve CD4 T cells obtained from relapsing-remitting (RR)-MS patients (n = 31) and healthy donors (HD) (n = 28). Analysis of an array of cytokines produced by Th17 cells revealed that expression of interleukin (IL)-21, tumour necrosis factor (TNF)-ß, IL-2 and IL-1R1 is significantly increased in Th17 cells derived from MS patients compared to healthy donor-derived cells. Interestingly, IL-1R1 expression is also increased in Th17 cells circulating in the blood of MS patients compared to healthy donors. Since IL-2, IL-21, TNF-ß, and IL-1R1 play a crucial role in the activation of immune cells, our data indicate that high expression of these molecules in Th17 cells from MS patients could be related to their high inflammatory status.

The RNA binding protein Sam68 controls T helper 1 differentiation and anti-mycobacterial response through modulation of miR-29.

Polarization of naive T cells into interferon (IFN)-γ-producing T helper 1 (Th1) cells is an essential event in the inflammatory response to pathogens. Herein, we identify the RNA binding protein Sam68 as a specific modulator of Th1 differentiation. Sam68-knockout (ko) naive T cells are strongly defective in IL-12-mediated Th1 polarization and express low levels of T-bet and Eomes. Consequently, Sam68-ko Th1 cells are significantly impaired in IFN-γ production. Moreover, we found that Sam68 is required for the induction of an inflammatory Th1 response during Mycobacterium bovis Bacillus Calmette-Guerin (BCG) infection, thus limiting bacterial dissemination in the lungs. Mechanistically, Sam68 directly binds to the microRNA miR-29, a negative regulator of Th1 response, and inhibits its expression during BCG infection. These findings uncover a novel post-transcriptional mechanism required for the Th1-mediated defense against intracellular pathogens and identify a new function for Sam68 in the regulation of the immune response.

Genetic diversity in the env V1-V2 region of proviral quasispecies from long-term controller MHC-typed cynomolgus macaques infected with SHIVSF162P4cy.

Intra-host evolution of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) has been shown by viral RNA analysis in subjects who naturally suppress plasma viremia to low levels, known as controllers. However, little is known about the variability of proviral DNA and the inter-relationships among contained systemic viremia, rate of reservoir reseeding and specific major histocompatibility complex (MHC) genotypes, in controllers. Here, we analysed the proviral DNA quasispecies of the env V1-V2 region, in PBMCs and in anatomical compartments of 13 long-term controller monkeys after 3.2 years of infection with simian/human immunodeficiency virus (SHIV)SF162P4cy. A considerable variation in the genetic diversity of proviral quasispecies was present among animals. Seven monkeys exhibited env V1-V2 proviral populations composed of both clusters of identical ancestral sequences and new variants, whereas the other six monkeys displayed relatively high env V1-V2 genetic diversity with a large proportion of diverse novel sequences. Our results demonstrate that in SHIVSF162P4cy-infected monkeys there exists a disparate pattern of intra-host viral diversity and that reseeding of the proviral reservoir occurs in some animals. Moreover, even though no particular association has been observed between MHC haplotypes and the long-term control of infection, a remarkably similar pattern of intra-host viral diversity and divergence was found within animals carrying the M3 haplotype. This suggests that in animals bearing the same MHC haplotype and infected with the same virus, viral diversity follows a similar pattern with similar outcomes and control of infection.

FoxP3 isoforms and PD-1 expression by T regulatory cells in multiple sclerosis.

Forkhead box P3 (FoxP3)+ regulatory T cells (Treg) are powerful mediators of immune regulation and immune homeostasis. In humans, Tregs are a heterogeneous population expressing surface markers which define phenotypically and functionally distinct subsets. Moreover, it is now clear that intracellular staining for FoxP3 does not unequivocally identify "true" suppressor cells, since several FoxP3 isoforms exist, and different reagents for FoxP3 detection are available. Here, we propose a strategy to identify potentially functional and suppressive Treg cells in an autoimmune disease like multiple sclerosis, and we suggest that in patients affected by this disease these cells are both reduced in number and functionally exhausted.