RESUMO
(1) Background: The influenza A/H1N1 pdm09 virus rapidly spread throughout the world. Despite the inflammatory and virus-degradation pathways described in the pathogenesis of influenza A virus (IAV) infection, little is known about the role of the single nucleotide polymorphisms (SNPs) in the genes involved in the processing and antigenic presentation-related mechanisms. (2) Methods: In this case-control study, we evaluated 17 SNPs in five genes (TAP1, TAP2, TAPBP, PSMB8, and PSMB9). One hundred and twenty-eight patients with influenza A/H1N1 infection (INF-P) and 111 healthy contacts (HC) were included; all of them are Mexican mestizo. (3) Results: In allele and genotype comparison, the rs241433/C allele (TAP2), as well as AG haplotype (rs3763365 and rs4148882), are associated with reduced risk for influenza A/H1N1 infection (p < 0.05). On the other hand, the rs2071888G allele (TAPBP) and GG haplotype (rs3763365 and rs9276810) are associated with a higher risk for influenza A/H1N1 infection. In addition, after adjustment for covariates, the association to a reduced risk for influenza A/H1N1 infection remains with rs241433/C allele (p < 0.0001, OR = 0.24, 95% CI = 0.13-0.43), and the association with TAPBP is also maintained with the G allele (p = 0.0095, OR = 1.89, 95% CI = 1.17-3.06) and GG genotype models (p < 0.05, OR = 2.18, 95% CI = 1.27-3.74). (4) Conclusion: The rs241433/C allele and AC genotype (TAP2) and the AG haplotype are associated with a reduced risk for influenza A/H1N1 infection. In addition, the rs2071888/G allele and GG genotype (TAPBP) and the GG haplotype are associated with a higher risk for developing influenza A/H1N1 infection in a Mexican mestizo population.
Assuntos
Apresentação de Antígeno/genética , Predisposição Genética para Doença/etnologia , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/epidemiologia , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença/epidemiologia , Genótipo , Haplótipos , Humanos , Influenza Humana/etnologia , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
B lymphocytes capture antigens from the surface of presenting cells by forming an immune synapse. Local secretion of lysosomes, which are guided to the synaptic membrane by centrosome repositioning, can facilitate the extraction of immobilized antigens. However, the molecular basis underlying their delivery to precise domains of the plasma membrane remains elusive. Here we show that microtubule stabilization, triggered by engagement of the B cell receptor, acts as a cue to release centrosome-associated Exo70, which is redistributed to the immune synapse. This process is coupled to the recruitment and activation of GEF-H1, which is required for assembly of the exocyst complex, used to promote tethering and fusion of lysosomes at the immune synapse. B cells silenced for GEF-H1 or Exo70 display defective lysosome secretion, which results in impaired antigen extraction and presentation. Thus, centrosome repositioning coupled to changes in microtubule stability orchestrates the spatial-temporal distribution of the exocyst complex to promote polarized lysosome secretion at the immune synapse.
Assuntos
Apresentação de Antígeno/genética , Linfócitos B/imunologia , Sinapses Imunológicas/genética , Fatores de Troca de Nucleotídeo Guanina Rho/genética , Proteínas de Transporte Vesicular/genética , Animais , Apresentação de Antígeno/imunologia , Antígenos de Superfície/genética , Antígenos de Superfície/imunologia , Membrana Celular/imunologia , Polaridade Celular/genética , Polaridade Celular/imunologia , Centrossomo/imunologia , Exocitose/genética , Exocitose/imunologia , Lisossomos/genética , Lisossomos/imunologia , Camundongos , Microtúbulos/genética , Microtúbulos/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologiaRESUMO
BACKGROUND: TcTLE is a nonamer peptide from Trypanosoma cruzi KMP-11 protein that is conserved among different parasite strains and that is presented by different HLA-A molecules from the A2 supertype. Because peptides presented by several major histocompatibility complex (MHC) supertypes are potential targets for immunotherapy, the aim of this study was to determine whether MHC molecules other than the A2 supertype present the TcTLE peptide. METHODOLOGY/PRINCIPAL FINDINGS: From 36 HLA-A2-negative chagasic patients, the HLA-A genotypes of twenty-eight patients with CD8+ T cells that recognized the TcTLE peptide using tetramer (twenty) or functional (eight) assays, were determined. SSP-PCR was used to identify the A locus and the allelic variants. Flow cytometry was used to analyze the frequency of TcTLE-specific CD8+ T cells, and their functional activity (IFN-γ, TNFα, IL-2, perforin, granzyme and CD107a/b production) was induced by exposure to the TcTLE peptide. All patients tested had TcTLE-specific CD8+ T cells with frequencies ranging from 0.07-0.37%. Interestingly, seven of the twenty-eight patients had HLA-A homozygous alleles: A*24 (5 patients), A*23 (1 patient) and A*01 (1 patient), which belong to the A24 and A1 supertypes. In the remaining 21 patients with HLA-A heterozygous alleles, the most prominent alleles were A24 and A68. The most common allele sub-type was A*2402 (sixteen patients), which belongs to the A24 supertype, followed by A*6802 (six patients) from the A2 supertype. Additionally, the A*3002/A*3201 alleles from the A1 supertype were detected in one patient. All patients presented CD8+ T cells producing at least one cytokine after TcTLE peptide stimulation. CONCLUSION/SIGNIFICANCE: These results show that TcTLE is a promiscuous peptide that is presented by the A24 and A1 supertypes, in addition to the A2 supertype, suggesting its potential as a target for immunotherapy.
Assuntos
Linfócitos T CD8-Positivos , Doença de Chagas , Epitopos de Linfócito T/imunologia , Antígeno HLA-A1 , Antígeno HLA-A2 , Antígeno HLA-A24 , Proteínas de Protozoários/imunologia , Trypanosoma cruzi/imunologia , Adulto , Idoso , Alelos , Apresentação de Antígeno/genética , Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/genética , Doença de Chagas/imunologia , Feminino , Genótipo , Antígeno HLA-A1/genética , Antígeno HLA-A1/imunologia , Antígeno HLA-A2/genética , Antígeno HLA-A2/imunologia , Antígeno HLA-A24/genética , Antígeno HLA-A24/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos/imunologiaRESUMO
The setting for the occurrence of an immune response is that of the need to cope with a vast array of different antigens from both pathogenic and non-pathogenic sources. When the first barriers against infection and innate defense fail, adaptive immune response enters the stage for recognition of the antigens by means of extremely variable molecules, namely immunoglobulins and T-cell receptors. The latter recognize the antigen exposed on cell surfaces, in the form of peptides presented by the HLA molecule. The first part of this review details the central role played by these molecules, establishing the close connection existing between their structure and their antigen presenting function.
Assuntos
Apresentação de Antígeno/imunologia , Antígenos HLA/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Alelos , Apresentação de Antígeno/genética , Antígenos HLA/genética , Humanos , Complexo Principal de Histocompatibilidade/genéticaRESUMO
The setting for the occurrence of an immune response is that of the need to cope with a vast array of different antigens from both pathogenic and non-pathogenic sources. When the first barriers against infection and innate defense fail, adaptive immune response enters the stage for recognition of the antigens by means of extremely variable molecules, namely immunoglobulins and T-cell receptors. The latter recognize the antigen exposed on cell surfaces, in the form of peptides presented by the HLA molecule. The first part of this review details the central role played by these molecules, establishing the close connection existing between their structure and their antigen presenting function.
O cenário no qual ocorre a resposta imune é o da necessidade de fazer frente a uma vasta gama de antígenos diferentes, de fontes patogênicas e não patogênicas. Quando as primeiras barreiras contra infecção e a defesa inata falham, a resposta imune adaptativa entra em campo, para efetuar o reconhecimento dos antígenos, utilizando, para esse fim, moléculas extremamente variáveis, que são as imunoglobulinas e os receptores de células-T. Estes últimos reconhecem o antígeno, exposto na superfície das células como peptídeo apresentado pelas moléculas HLA. A primeira parte desta revisão detalha o papel central dessas moléculas, estabelecendo a conexão que existe entre a estrutura e a função de apresentação de antígenos.
Assuntos
Humanos , Apresentação de Antígeno/imunologia , Antígenos HLA/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Alelos , Apresentação de Antígeno/genética , Antígenos HLA/genética , Complexo Principal de Histocompatibilidade/genéticaRESUMO
We have initially shown that DC/ApoNec vaccine can induce protection against the poorly immunogenic B16F1 melanoma in mice. The population of DC obtained for vaccination after 7days culture with murine GM-CSF is heterogeneous and presents about 60% of CD11c+ DC. Therefore, our purpose was to identify the phenotype of the cells obtained after differentiation and its immunogenicity once injected. DC were separated with anti-CD11c microbeads and the two populations identified in terms of CD11c positivity (DC+ and DC-) were also studied. Approximately 26.6% of the cells in DC+ fraction co-expressed CD11c+ and F4/80 markers and 75.4% were double positive for CD11c and CD11b markers. DC+ fraction also expressed Ly6G. DC- fraction was richer in CD11c-/F4/80+ macrophages (44.7%), some of which co-expressed Ly6G (41.8%), and F4/80-/Ly6-G+ neutrophils (34.6%). Both DC+ and DC- fractions displayed similar capacity to phagocyte and endocyte antigens and even expressed levels of MHC Class II and CD80, CD83 and CD86 costimulatory molecules similar to those in the DC fraction. However, only DC/ApoNec vaccine was capable to induce protection in mice (p<0.01). After 24h co-culture, no detectable level of IL-12 was recorded in DC/ApoNec vaccine, either in supernatant or intracellularly. Therefore, the protection obtained with DC/ApoNec vaccine seemed to be independent of the vaccine's ability to secrete this inflammatory cytokine at the time of injection. In conclusion, we demonstrated that all cell types derived from the culture of mouse bone marrow with GM-CSF are necessary to induce antitumor protection in vivo.
Assuntos
Apresentação de Antígeno/imunologia , Células da Medula Óssea/imunologia , Antígeno CD11c/imunologia , Vacinas Anticâncer/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Melanoma Experimental/imunologia , Melanoma Experimental/prevenção & controle , Animais , Apresentação de Antígeno/genética , Antígenos de Superfície/genética , Antígenos de Superfície/imunologia , Antígenos de Superfície/metabolismo , Células da Medula Óssea/metabolismo , Antígeno CD11c/genética , Vacinas Anticâncer/genética , Vacinas Anticâncer/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem Celular Tumoral , Técnicas de Cocultura , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Interleucina-12/genética , Interleucina-12/imunologia , Interleucina-12/metabolismo , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Masculino , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neutrófilos/imunologia , Neutrófilos/metabolismoRESUMO
BACKGROUND: We have recently reported that chemotherapeutic agents in ultra low noncytotoxic concentrations may block the ability of tumor cells to suppress functional activation of dendritic cells (DCs). METHODS: HCT-116 human colon cancer cells were treated with 0.5 nM paclitaxel (PAC) or 2 nM doxorubicin (DOX) with the aim of defining the immunogenic changes induced by ultra low noncytotoxic concentrations of antineoplastic chemotherapeutic agents. Genetic alterations were screened by DNA microarray that revealed increased expression of genes involved in antigen processing and presentation, including the heat-shock protein, calmodulin, and proteasome 26 genes. As the proteins encoded by these genes are involved in the cytosolic route of antigen processing machinery, we next evaluated whether PAC and DOX in noncytotoxic concentrations changed expression of MHC class I antigen processing machinery (APM) components in three different colon cancer cell lines. RESULTS: Our results showed that PAC and DOX increased the intracellular expression of APM proteins, including calmodulin, LMP2, LMP7, TAP1 and tapasin. The biological significance of modulation of antigen processing and presentation proteins in tumor cells by ultra low nontoxic concentrations of chemotherapeutic drugs was revealed when non-treated and treated tumor cells were used as a source of tumor antigens for the generation of tumor-specific cytotoxic T cells (CTLs) in vitro. We demonstrated that (i) DCs that engulf tumor cells pretreated with noncytotoxic concentrations of chemotherapeutic agents induced CTLs with a higher cytotoxic potential than DCs loaded with nontreated tumor cells, and (ii) CTLs induced by tumor lysate-pulsed DCs killed live tumor cells more efficiently if these tumor cells were pretreated with noncytotoxic concentrations of chemotherapeutic drugs. CONCLUSIONS: These results demonstrate that chemomodulation of human tumor cells with noncytotoxic concentrations of chemotherapeutic agents increases tumor immunogenicity and results in the generation of more efficient DC vaccines and CTLs, which can be used for cell-based anticancer immunotherapies.
Assuntos
Antineoplásicos/farmacologia , Citotoxicidade Imunológica/efeitos dos fármacos , Células Dendríticas/imunologia , Linfócitos T Citotóxicos/imunologia , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Apresentação de Antígeno/genética , Calmodulina/genética , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Técnicas de Cocultura , Neoplasias do Colo/genética , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Cisteína Endopeptidases/genética , Citotoxicidade Imunológica/genética , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Células HT29 , Humanos , Proteínas de Membrana Transportadoras/genética , Análise de Sequência com Séries de Oligonucleotídeos , Paclitaxel/farmacologia , Complexo de Endopeptidases do Proteassoma/genética , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/metabolismoRESUMO
Salmonella enterica serovar Typhimurium can enter non-phagocytic cells, such as intestinal epithelial cells, by virtue of a Type Three Secretion System (TTSS) encoded in the Salmonella Pathogenicity Island 1 (SPI-1), which translocates bacterial effector molecules into the host cell. Salmonella can also be taken up by dendritic cells (DCs). Although the role of SPI-1 in non-phagocytic cell invasion is well established, its contribution to invasion of phagocytic cells has not been evaluated. Here, we have tested the invasive capacity of a S. Typhimurium strain lacking a key component of its TTSS-1 (DeltaInvC) leading to defective translocation of SPI-1-encoded effectors. Whereas this mutant Salmonella strain was impaired for invasion of non-phagocytic cells, it was taken up by DCs at a significantly higher rate than wild-type Salmonella. Similar to wild-type Salmonella, the DeltaInvC mutant strain retained the capacity to avoid antigen presentation to T cells. However, mice infected with the DeltaInvC mutant strain showed higher survival rate and reduced organ colonization. Our data suggest that, besides promoting phagocytosis by non-phagocytic cells, SPI-1 modulates the number of bacteria that enters DCs. The SPI-1 could be considered not only as an inducer of epithelial cell invasion but as a controller of DC entry.
Assuntos
Proteínas de Bactérias/imunologia , Translocação Bacteriana/imunologia , Células Dendríticas/imunologia , Células Epiteliais/imunologia , Salmonella typhimurium/imunologia , Salmonella typhimurium/patogenicidade , Animais , Apresentação de Antígeno/genética , Apresentação de Antígeno/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Translocação Bacteriana/genética , Células Dendríticas/metabolismo , Células Dendríticas/microbiologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Deleção de Genes , Camundongos , Camundongos Transgênicos , Fagocitose/genética , Fagocitose/imunologia , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Linfócitos T/microbiologiaRESUMO
BACKGROUND: Neurovirulent Venezuelan equine encephalitis virus (VEEV) causes lethal encephalitis in equines and is transmitted to humans by mosquitoes. VEEV is highly infectious when transmitted by aerosol and has been developed as a bio-warfare agent, making it an important pathogen to study from a military and civilian standpoint. Molecular mechanisms of VEE pathogenesis are poorly understood. To study these, the gene expression profile of VEEV infected mouse brains was investigated. Changes in gene expression were correlated with histological changes in the brain. In addition, a molecular framework of changes in gene expression associated with progression of the disease was studied. RESULTS: Our results demonstrate that genes related to important immune pathways such as antigen presentation, inflammation, apoptosis and response to virus (Cxcl10, CxCl11, Ccl5, Ifr7, Ifi27 Oas1b, Fcerg1,Mif, Clusterin and MHC class II) were upregulated as a result of virus infection. The number of over-expressed genes (>1.5-fold level) increased as the disease progressed (from 197, 296, 400, to 1086 at 24, 48, 72 and 96 hours post infection, respectively). CONCLUSION: Identification of differentially expressed genes in brain will help in the understanding of VEEV-induced pathogenesis and selection of biomarkers for diagnosis and targeted therapy of VEEV-induced neurodegeneration.
Assuntos
Encéfalo/imunologia , Encéfalo/patologia , Encefalomielite Equina Venezuelana/genética , Encefalomielite Equina Venezuelana/imunologia , Imunidade/genética , Inflamação/genética , Animais , Apresentação de Antígeno/genética , Antígenos/imunologia , Apoptose/genética , Encéfalo/metabolismo , Encefalomielite Equina Venezuelana/patologia , Amarelo de Eosina-(YS)/metabolismo , Perfilação da Expressão Gênica , Hematoxilina/metabolismo , Imuno-Histoquímica , Masculino , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de SobrevidaRESUMO
High-molecular-weight components (PI) of Ascaris suum suppress both cell-mediated and humoral responses against ovalbumin (OVA) via an IL-4/IL-10-dependent mechanism. The aim of this work was to investigate the effect of PI on the ability of APC to activate T cells and the role of IL-10 in this process. Flow cytometry analyses of MHC class II, CD80, CD86 and CD40 molecules on LN cells from mice immunized with OVA or OVA+PI showed that PI inhibits expression of these molecules on unfractionated cells and on purified CD11c(+) cells. A low proliferative response was obtained when OVA-specific TCR-Tg T cells were incubated with CD11c(+) cells from OVA+PI-immunized mice pulsed with OVA, when compared to those incubated with cells from OVA-immunized mice. Similar results were obtained using as APC CD11c(+) cells from OVA-immunized mice pulsed with OVA+PI, which also expressed less of the four markers. The inhibitory effect of PI on both the expression of costimulatory molecules and the induction of T cell proliferation was abolished in IL-10-deficient mice. Our data indicate that the potent immunosuppressive effect of A. suum extract components on the host immune system is primarily related to their property of down-regulating the Ag-presenting ability of DC via an IL-10-mediated mechanism.