A Vaccine Encoding Conserved Promiscuous HIV CD4 Epitopes Induces Broad T Cell Responses in Mice Transgenic to Multiple Common HLA Class II Molecules

Current HIV vaccine approaches are focused on immunogens encoding whole HIV antigenic proteins that mainly elicit cytotoxic CD8+ responses. Mounting evidence points toward a critical role for CD4+ T cells in the control of immunodeficiency virus replication, probably due to cognate help. Vaccine-induced CD4+ T cell responses might, therefore, have a protective effect in HIV replication. In addition, successful vaccines may have to elicit responses to multiple epitopes in a high proportion of vaccinees, to match the highly variable circulating strains of HIV. Using rational vaccine design, we developed a DNA vaccine encoding 18 algorithm-selected conserved, “promiscuous” (multiple HLA-DR-binding) B-subtype HIV CD4 epitopes - previously found to be frequently recognized by HIV-infected patients. We assessed the ability of the vaccine to induce broad T cell responses in the context of multiple HLA class II molecules using different strains of HLA class II- transgenic mice (-DR2, -DR4, -DQ6 and -DQ8). Mice displayed CD4+ and CD8+ T cell responses of significant breadth and magnitude, and 16 out of the 18 encoded epitopes were recognized. By virtue of inducing broad responses against conserved CD4+ T cell epitopes that can be recognized in the context of widely diverse, common HLA class II alleles, this vaccine concept may cope both with HIV genetic variability and increased population coverage. The vaccine may thus be a source of cognate help for HIV-specific CD8+ T cells elicited by conventional immunogens, in a wide proportion of vaccinees

Plasma Cytokine Profile in Tropical Endomyocardial Fibrosis: Predominance of TNF-a, IL-4 and IL-10

Background: the participation of immune/inflammatory mechanisms in the pathogenesis of tropical endomyocardial fibrosis (EMF) has been suggested by the finding of early blood and myocardial eosinophilia. However, the inflammatory activation status of late-stage EMF patients is still unknown.Methodology/Principal findings: We evaluated pro- and anti-inflammatory cytokine levels in plasma samples from late stage EMF patients. Cytokine levels of Tumor Necrosis Factor (TNF)-alpha, Interferon (IFN)-gamma, Interleukin (IL)-2, IL-4, IL-6, and IL-10 were assayed in plasma samples from 27 EMF patients and compared with those of healthy control subjects. All EMF patients displayed detectable plasma levels of at least one of the cytokines tested. We found that TNF-alpha, IL-6, IL-4, and IL-10 were each detected in at least 74% of tested sera, and plasma levels of IL-10, IL-4, and TNF-alpha were significantly higher than those of controls. Plasma levels of such cytokines positively correlated with each other.Conclusions/Significance: the mixed pro-and anti-inflammatory/Th2circulating cytokine profile in EMF is consistent with the presence of a persistent inflammatory stimulus. On the other hand, the detection of increased levels of TNF-alpha may be secondary to the cardiovascular involvement observed in these patients, whereas IL-4 and IL-10 may have been upregulated as a homeostatic mechanism to buffer both production and deleterious cardiovascular effects of pro-inflammatory cytokines. Further studies might establish whether these findings play a role in disease pathogenesis.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo, Sch Med, Inst Heart InCor, Immunol Lab, São Paulo, BrazilUniv São Paulo, Sch Med, Div Clin Immunol & Allergy, São Paulo, BrazilUniv São Paulo, Sch Med, Inst Heart InCor, Cardiomyopathy Unit, São Paulo, BrazilProSangue Fdn, São Paulo, BrazilInst Investigat Immunol, INCT, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, Div Immunol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Immunol & Parasitol, Div Immunol, São Paulo, BrazilWeb of Scienc

Serum cytokine responses over the entire clinical-immunological spectrum of human leishmania (l.) infantum chagasi infection

The clinical-immunological spectrum of human Leishmania (L.) infantum chagasi infection in Amazonian Brazil was recently reviewed based on clinical, DTH, and IFAT (IgG) evaluations that identified five profiles: three asymptomatic (asymptomatic infection, AIsubclinical resistant infection, SRIand indeterminate initial infection, III) and two symptomatic (symptomatic infection, SIAmerican visceral leishmaniasis, AVLand subclinical oligosymptomatic infection, SOI). TNF-alpha, IL-4, IL-6, and IL-10 serum cytokines were analyzed using multiplexed Cytometric Bead Array in 161 samples from endemic areas in the Brazilian Amazon: SI [AVL] (21 cases), III (49), SRI (19), SOI (12), AI (36), and a control group [CG] (24). The highest IL-6 serumlevels were observed in the SI profile (AVL)higher IL-10 serum levels were observed in SI than in SOI or CG and in AI and III than in SOIhigher TNF-alpha serum levels were seen in SI than in CG. Positive correlations were found between IL-6 and IL-10 serum levels in the SI and III profiles and between IL-6 and TNF-alpha and between IL-4 and TNF-alpha in the III profile. These results provide strong evidence for associating IL-6 and IL-10 with the immunopathogenesis of AVL and help clarify the role of these cytokines in the infection spectrum.Instituto Evandro Chagas (Secretaria de Vigilancia em Saude, Ministerio da Saude, Brazil)Nucleo de Medicina Tropical (Universidade Federal do Para, Brazil)Laboratorio de Investigacao Medica (LIM)-50 (Hospital de Clinicas (HC)-Faculdade de Medicina (FM)-Universidade de Sao Paulo (USP), Brazil)Sao Paulo Research Foundation (FAPESP) [2006/56319-1]Parasitology Department, Evandro Chagas Institute, Surveillance Secretary of Health, Ministry of Health, Ananindeua, PA, BrazilAlbert Einstein Israelite Hospital, São Paulo, SP, BrazilDivision of Immunology, Federal University of São Paulo, São Paulo, SP, BrazilPathology Department, Medical School of São Paulo University, São Paulo, SP, BrazilTropical Medicine Nucleus, Federal University of Pará, Belém, PA, BrazilDivision of Immunology, Federal University of São Paulo, São Paulo, SP, BrazilFAPESP: 2006/56319-1Web of Scienc

Serum Cytokine Responses over the Entire Clinical-Immunological Spectrum of Human Leishmania (L.) infantum chagasi

The clinical-immunological spectrum of human Leishmania (L.) infantum chagasi infection in Amazonian Brazil was recently reviewed based on clinical, DTH, and IFAT (IgG) evaluations that identified five profiles: three asymptomatic (asymptomatic infection, AI; subclinical resistant infection, SRI; and indeterminate initial infection, III) and two symptomatic (symptomatic infection, SI; American visceral leishmaniasis, AVL; and subclinical oligosymptomatic infection, SOI). TNF-α, IL-4, IL-6, and IL-10 serum cytokines were analyzed using multiplexed Cytometric Bead Array in 161 samples from endemic areas in the Brazilian Amazon: SI [AVL] (21 cases), III (49), SRI (19), SOI (12), AI (36), and a control group [CG] (24). The highest IL-6 serum levels were observed in the SI profile (AVL); higher IL-10 serum levels were observed in SI than in SOI or CG and in AI and III than in SOI; higher TNF-α serum levels were seen in SI than in CG. Positive correlations were found between IL-6 and IL-10 serum levels in the SI and III profiles and between IL-6 and TNF-α and between IL-4 and TNF-α in the III profile. These results provide strong evidence for associating IL-6 and IL-10 with the immunopathogenesis of AVL and help clarify the role of these cytokines in the infection spectrum

Dendritic Cell Targeting Using a DNA Vaccine Induces Specific Antibodies and CD4+ T Cells to the Dengue Virus Envelope Protein Domain III

Dengue fever has become a global threat, causing millions of infections every year. An effective vaccine against all four serotypes of dengue virus (DENV) has not been developed yet. Among the different vaccination strategies available today, DNA vaccines are safe and practical, but currently induce relatively weak immune responses in humans. In order to improve immunogenicity, antigens may be targeted to dendritic cells (DCs), the main antigen presenting cells and orchestrators of the adaptive immune response, inducing T and B cell activation. It was previously shown that a DNA vaccine encoding a fusion protein comprised of an antigen and a single-chain Fv antibody (scFv) specific for the DC endocytic receptor DEC205 induced strong immune responses to the targeted antigen. In this work, we evaluate this strategy to improve the immunogenicity of dengue virus (DENV) proteins. Plasmids encoding the scFv αDEC205, or an isotype control (scFv ISO), fused to the DENV2 envelope protein domain III (EDIII) were generated, and EDIII specific immune responses were evaluated in immunized mice. BALB/c mice were intramuscularly (i.m.) immunized three times with plasmid DNAs encoding either scDEC-EDIII or scISO-EDIII followed by electroporation. Analyses of the antibody responses indicated that EDIII fusion with scFv targeting the DEC205 receptor significantly enhanced serum anti-EDIII IgG titers that inhibited DENV2 infection. Similarly, mice immunized with the scDEC-EDIII plasmid developed a robust CD4+ T cell response to the targeted antigen, allowing the identification of two linear epitopes recognized by the BALB/c haplotype. Taken together, these results indicate that targeting DENV2 EDIII protein to DCs using a DNA vaccine encoding the scFv αDEC205 improves both antibody and CD4+ T cell responses. This strategy opens perspectives for the use of DNA vaccines that encode antigens targeted to DCs as a strategy to increase immunogenicity

Broad and Cross-Clade CD4(+) T-Cell Responses Elicited by a DNA Vaccine Encoding Highly Conserved and Promiscuous HIV-1 M-Group Consensus Peptides

T-cell based vaccine approaches have emerged to counteract HIV-1/AIDS. Broad, polyfunctional and cytotoxic CD4(+) T-cell responses have been associated with control of HIV-1 replication, which supports the inclusion of CD4(+) T-cell epitopes in vaccines. A successful HIV-1 vaccine should also be designed to overcome viral genetic diversity and be able to confer immunity in a high proportion of immunized individuals from a diverse HLA-bearing population. In this study, we rationally designed a multiepitopic DNA vaccine in order to elicit broad and cross-clade CD4(+) T-cell responses against highly conserved and promiscuous peptides from the HIV-1 M-group consensus sequence. We identified 27 conserved, multiple HLA-DR-binding peptides in the HIV-1 M-group consensus sequences of Gag, Pol, Nef, Vif, Vpr, Rev and Vpu using the TEPITOPE algorithm. The peptides bound in vitro to an average of 12 out of the 17 tested HLA-DR molecules and also to several molecules such as HLA-DP, -DQ and murine IA(b) and IA(d). Sixteen out of the 27 peptides were recognized by PBMC from patients infected with different HIV-1 variants and 72% of such patients recognized at least 1 peptide. Immunization with a DNA vaccine (HIVBr27) encoding the identified peptides elicited IFN-gamma secretion against 11 out of the 27 peptides in BALB/c mice; CD4(+) and CD8(+) T-cell proliferation was observed against 8 and 6 peptides, respectively. HIVBr27 immunization elicited cross-clade T-cell responses against several HIV-1 peptide variants. Polyfunctional CD4(+) and CD8(+) T cells, able to simultaneously proliferate and produce IFN-gamma and TNF-alpha, were also observed. This vaccine concept may cope with HIV-1 genetic diversity as well as provide increased population coverage, which are desirable features for an efficacious strategy against HIV-1/AIDS.Brazilian National Research Council (CNPq) [420166/2005-0]Brazilian National Research Council (CNPq)Sao Paulo State Research Funding Agency (FAPESP) [2004/15856-9, 2006/50096-0, 2008/57881-0]Sao Paulo State Research Funding Agency (FAPESP)Brazilian Program for STD and AIDS, Ministry of HealthBrazilian Program for STD and AIDS, Ministry of Health [914/BRA/3014-UNESCO/Kallas]Sao Paulo City Health Department [2004-0.168.922-7/Kallas]Sao Paulo City Health DepartmentBrazilian Council for Scientific and Technological Development - CNPq productivity awardsBrazilian Council for Scientific and Technological Development CNPq productivity award

Epigenetic fingerprint in endometrial carcinogenesis: the hypothesis of a uterine field cancerization.

"Abstract. Transcriptional silencing by CpG island hypermethylation plays a critical role in endometrial carcinogenesis. In a collection of benign, premalignant and malignant endometrial lesions, a methylation profile of a complete gene panel, such steroid receptors (ERα, PR), DNA mismatch repair (hMLH1), tumor-suppressor genes (CDKN2A\/P16 and CDH1\/E-CADHERIN) and WNT pathway inhibitors (SFRP1, SFRP2, SFRP4, SFRP5) was investigated in order to demonstrate their pathogenetic role in endometrial lesions. Our results indicate that gene hypermethylation may be an early event in endometrial endometrioid tumorigenesis. Particularly, ERα, PR, hMLH1, CDKN2A\/P16, SFRP1, SFRP2 and SFRP5 revealed a promoter methylation status in endometrioid carcinoma, whereas SFRP4 showed demethylation in cancer. P53 immunostaining showed weak-focal protein expression level both in hyperplasic lesions and in endometrioid cancer. Non-endometrioid cancers showed very low levels of epigenetic methylations, but strong P53 protein positivity. Fisher exact test revealed a statistically significant association between hMLH1, CDKN2A\/P16 and SFRP1 genes methylation and endometrioid carcinomas and between hMLH1 gene methylation and peritumoral endometrium (p < 0.05). Our data confirm that the methylation profile of the peritumoral endometrium is different from the altered molecular background of benign endometrial polyps and hyperplasias. Therefore, our findings suggest that the methylation of hMLH1, CDKN2A\/P16 and SFRP1 may clearly distinguish between benign and malignant lesions. Finally, this study assessed that the use of an epigenetic fingerprint may improve the current diagnostic tools for a better clinical management of endometrial lesions.

A DNA Vaccine Encoding Multiple HIV CD4 Epitopes Elicits Vigorous Polyfunctional, Long-Lived CD4+ and CD8+ T Cell Responses

T-cell based vaccines against HIV have the goal of limiting both transmission and disease progression by inducing broad and functionally relevant T cell responses. Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection. CD4+ T cells are important for the generation and maintenance of functional CD8+ cytotoxic T cells. We have recently developed a DNA vaccine encoding 18 conserved multiple HLA-DR-binding HIV-1 CD4 epitopes (HIVBr18), capable of eliciting broad CD4+ T cell responses in multiple HLA class II transgenic mice. Here, we evaluated the breadth and functional profile of HIVBr18-induced immune responses in BALB/c mice. Immunized mice displayed high-magnitude, broad CD4+/CD8+ T cell responses, and 8/18 vaccine-encoded peptides were recognized. In addition, HIVBr18 immunization was able to induce polyfunctional CD4+ and CD8+ T cells that proliferate and produce any two cytokines (IFNγ/TNFα, IFNγ/IL-2 or TNFα/IL-2) simultaneously in response to HIV-1 peptides. For CD4+ T cells exclusively, we also detected cells that proliferate and produce all three tested cytokines simultaneously (IFNγ/TNFα/IL-2). The vaccine also generated long-lived central and effector memory CD4+ T cells, a desirable feature for T-cell based vaccines. By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4+ T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8+ T cells and antibody responses- elicited by other HIV immunogens

Immunodominant antibody responses directed to SARS-CoV-2 hotspot mutation sites and risk of immune escape

IntroductionConsidering the likely need for the development of novel effective vaccines adapted to emerging relevant CoV-2 variants, the increasing knowledge of epitope recognition profile among convalescents and afterwards vaccinated with identification of immunodominant regions may provide important information.MethodsWe used an RBD peptide microarray to identify IgG and IgA binding regions in serum of 71 COVID-19 convalescents and 18 vaccinated individuals. ResultsWe found a set of immunodominant RBD antibody epitopes, each recognized by more than 30% of the tested cohort, that differ among the two different groups and are within conserved regions among betacoronavirus. Of those, only one peptide, P44 (S415-429), recognized by 68% of convalescents, presented IgG and IgA antibody reactivity that positively correlated with nAb titers, suggesting that this is a relevant RBD region and a potential target of IgG/IgA neutralizing activity.DiscussionThis peptide is localized within the area of contact with ACE-2 and harbors the mutation hotspot site K417 present in gamma (K417T), beta (K417N), and omicron (K417N) variants of concern. The epitope profile of vaccinated individuals differed from convalescents, with a more diverse repertoire of immunodominant peptides, recognized by more than 30% of the cohort. Noteworthy, immunodominant regions of recognition by vaccinated coincide with mutation sites at Omicron BA.1, an important variant emerging after massive vaccination. Together, our data show that immune pressure induced by dominant antibody responses may favor hotspot mutation sites and the selection of variants capable of evading humoral response