RESUMO
Introduction: While there has been considerable progress in the development of vaccines against SARS-CoV-2, largely based on the S (spike) protein of the virus, less progress has been made with vaccines delivering different viral antigens with cross-reactive potential. Methods: In an effort to develop an immunogen with the capacity to induce broad antigen presentation, we have designed a multi-patch synthetic candidate containing dominant and persistent B cell epitopes from conserved regions of SARS-CoV-2 structural proteins associated with long-term immunity, termed CoV2-BMEP. Here we describe the characterization, immunogenicity and efficacy of CoV2-BMEP using two delivery platforms: nucleic acid DNA and attenuated modified vaccinia virus Ankara (MVA). Results: In cultured cells, both vectors produced a main protein of about 37 kDa as well as heterogeneous proteins with size ranging between 25-37 kDa. In C57BL/6 mice, both homologous and heterologous prime/boost combination of vectors induced the activation of SARS-CoV-2-specific CD4 and CD8 T cell responses, with a more balanced CD8+ T cell response detected in lungs. The homologous MVA/MVA immunization regimen elicited the highest specific CD8+ T cell responses in spleen and detectable binding antibodies (bAbs) to S and N antigens of SARS-CoV-2. In SARS-CoV-2 susceptible k18-hACE2 Tg mice, two doses of MVA-CoV2-BMEP elicited S- and N-specific bAbs as well as cross-neutralizing antibodies against different variants of concern (VoC). After SARS-CoV-2 challenge, all animals in the control unvaccinated group succumbed to the infection while vaccinated animals with high titers of neutralizing antibodies were fully protected against mortality, correlating with a reduction of virus infection in the lungs and inhibition of the cytokine storm. Discussion: These findings revealed a novel immunogen with the capacity to control SARS-CoV-2 infection, using a broader antigen presentation mechanism than the approved vaccines based solely on the S antigen.
Assuntos
COVID-19 , Vacinas Virais , Humanos , Animais , Camundongos , Vacinas contra COVID-19 , Vetores Genéticos , SARS-CoV-2 , COVID-19/prevenção & controle , Camundongos Endogâmicos C57BL , Vaccinia virus/genéticaAssuntos
Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/terapia , Atenção à Saúde/normas , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Betacoronavirus , COVID-19 , Atenção à Saúde/organização & administração , Planejamento em Desastres/organização & administração , Planejamento em Desastres/normas , Humanos , Pandemias , SARS-CoV-2 , EspanhaRESUMO
Altered and infected cells are eliminated by CD8+ cytotoxic T lymphocytes. This requires production of antigenic peptides mostly in the cytosol, transport to the endoplasmic reticulum (ER) by the transporter associated with antigen processing (TAP), and cell surface presentation by major histocompatibility complex class I (MHC-I). Strikingly, antigen presentation occurs without TAP, although it is inefficient and associated to human pathology. TAP-independent peptides derive both from membrane and secreted proteins, as well as cytosolic ones. The efficiency of TAP-independent presentation may be impacted by the availability of receptive MHC-I, and in turn by the functional presence in the ER of the peptide-loading complex, itself anchored on TAP. Without TAP, surface expression of human leukocyte antigen (HLA)-B allotypes varies widely, with those presenting a broader peptide repertoire among the most TAP-independent. Much remains to be learned on the alternative cellular pathways for antigen presentation in the absence of TAP.
Assuntos
Transportadores de Cassetes de Ligação de ATP , Apresentação de Antígeno , Retículo Endoplasmático , Antígenos de Histocompatibilidade Classe I , Transportadores de Cassetes de Ligação de ATP/metabolismo , Linfócitos T CD8-Positivos , Retículo Endoplasmático/metabolismo , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , HumanosRESUMO
Certain host genetic variants, especially in the human leucocyte antigen (HLA) region, are associated with different progression of HIV-1-induced diseases and AIDS. Long term non progressors (LTNP) represent only the 2% of infected patients but are especially relevant because of their efficient HIV control. In this work we present a global analysis of genetic data in the large national multicenter cohort of Spanish LTNP, which is compared with seronegative individuals and HIV-positive patients. We have analyzed whether several single-nucleotide polymorphisms (SNPs) including in key genes and certain HLA-A and B alleles could be associated with a specific HIV phenotype. A total of 846 individuals, 398 HIV-1-positive patients (213 typical progressors, 55 AIDS patients, and 130 LTNPs) and 448 HIV-negative controls, were genotyped for 15 polymorphisms and HLA-A and B alleles. Significant differences in the allele frequencies among the studied populations identified 16 LTNP-associated genetic factors, 5 of which were defined for the first time as related to LTNP phenotype: the protective effect of HLA-B39, and the detrimental impact of HLA-B18, -A24, -B08 and -A29. The remaining eleven polymorphisms confirmed previous publications, including the protective alleles HLA-B57, rs2395029 (HCP5), HLA bw4 homozygosity, HLA-B52, HLA-B27, CCR2 V64I, rs9264942 (HLA-C) and HLA-A03; and the risk allele HLA bw6 homozygosity. Notably, individual Spanish HIV-negative individuals had an average of 0.12 protective HLA alleles and SNPs, compared with an average of 1.43 protective alleles per LTNP patient, strongly suggesting positive selection of LTNP. Finally, stratification of LTNP according to viral load showed a proportional relationship between the frequency of protective alleles with control of viral load. Interestingly, no differences in the frequency of protection/risk polymorphisms were found between elite controllers and LTNPs maintaining viral loads <2.000 copies/mL throughout the follow-up.
Assuntos
Síndrome da Imunodeficiência Adquirida/genética , HIV-1 , Antígenos HLA/genética , Polimorfismo de Nucleotídeo Único , Carga Viral , Síndrome da Imunodeficiência Adquirida/sangue , Adolescente , Adulto , Idoso , Progressão da Doença , Feminino , Antígenos HLA/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , EspanhaRESUMO
Peptides generated by proteases in the cytosol must be translocated to endoplasmic reticulum lumen by the transporter associated with antigen processing (TAP) prior to their assembly with major histocompatibility complex (MHC) class I molecules. Nonfunctional TAP complexes produce a drastic decrease of the MHC class I/peptide complexes presented on the cell surface. Previously, the cellular MHC class I ligandome from TAP-deficient cell lines was determined, but similar analysis from normal tissues remains incomplete. Using high-throughput mass spectrometry to analyze the MHC-bound peptide pools isolated from ex vivo spleen cells of TAP-deficient mice, we identified 210 TAP-independent ligands naturally presented by murine MHC class I molecules. This ligandome showed increased peptide lengths, presence of multiple nested set peptides, and low theoretical MHC binding affinity. The gene ontology enrichment analysis of parental proteins of this TAP-independent subligandome showed almost exclusively enrichment in tissue-specific biological processes related to the immune system as would be expected. Also, cellular components of the extracellular space (namely proteins outside the cell but still within the organism excluding the extracellular matrix) were specifically associated with TAP-independent antigen processing from these ex vivo mice cells. In addition, functional protein association network analysis revealed low protein-protein interactions between parental proteins from the TAP-independent ligandome. Finally, predominant endoproteolytic peptidase specificity for Leu/Phe residues in the P1 position of the scissile bond at both ligand termini was found for the ex vivo TAP-independent ligands. These data indicate that the TAP-independent ligandome from ex vivo cells derives from a more diverse collection of both endoprotease activities and parental proteins and where the cell origin and contribution of the extracellular environment are more relevant than in its equivalent cell lines.
Assuntos
Antígenos de Histocompatibilidade Classe I/genética , Ligantes , Peptídeos/genética , Baço/metabolismo , Animais , Apresentação de Antígeno/genética , Apresentação de Antígeno/imunologia , Citosol/metabolismo , Retículo Endoplasmático/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Camundongos , Peptídeos/isolamento & purificação , Ligação Proteica/genética , Transporte Proteico/genética , Proteólise , Baço/químicaRESUMO
Cytomegaloviruses (CMVs) present singular features that are particularly advantageous for human vaccine development, a current medical need. Vaccines that induce neutralizing antibodies are among the most successful and efficacious available. However, chronic and persistent human infections, pathogens with high variability of exposed proteins, as well as tumors, highlight the need for developing novel vaccines inducing strong and long-lasting cellular immune responses mediated by effector or effector memory CD8+ cytotoxic T lymphocytes. CMVs induce the most potent CD8+ T lymphocyte response to a pathogen known in each of their hosts, maintain and even increase it for life for selected antigens, in what is known as the ever growing inflationary memory, and maintain an effector memory status due to recent and repeated antigen stimulation that endows these inflationary T lymphocytes with superior and faster protective potency. In addition to these CMV singularities, this family of viruses has two more common favorable features: they can superinfect an already infected host, which is needed in face of the high CMV prevalence, and they can harbor very large segments of foreign DNA at many different genomic sites. All these properties endow CMVs with a singular potential to be used as human vaccine vectors. Current developments with most of the recombinant CMV-based vaccine candidates that have been tested in animal models against clinically relevant viral and bacterial infections and for their use in tumor immunotherapy are reviewed herein. Since CMV vectors should be designed to avoid the risk of disease in immunocompromised individuals, special attention is also paid to attenuated vectors. Taken together, the results support the future use of CMV-based vaccine vectors to induce protective CD8+ T lymphocyte responses in humans, mainly against viral infections and as anti-tumor vaccines.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Citomegalovirus/genética , Portadores de Fármacos , Vetores Genéticos , Vacinas Virais/imunologia , Descoberta de Drogas/métodos , Humanos , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Vacinas Virais/genéticaRESUMO
The maintenance of T-cell homeostasis must be tightly regulated. Here, we have identified a coordinated role of Poly(ADP-ribose) polymerase-1 (PARP-1) and PARP-2 in maintaining T-lymphocyte number and function. Mice bearing a T-cell specific deficiency of PARP-2 in a PARP-1-deficient background showed defective thymocyte maturation and diminished numbers of peripheral CD4+ and CD8+ T-cells. Meanwhile, peripheral T-cell number was not affected in single PARP-1 or PARP-2-deficient mice. T-cell lymphopenia was associated with dampened in vivo immune responses to synthetic T-dependent antigens and virus, increased DNA damage and T-cell death. Moreover, double-deficiency in PARP-1/PARP-2 in T-cells led to highly aggressive T-cell lymphomas with long latency. Our findings establish a coordinated role of PARP-1 and PARP-2 in T-cell homeostasis that might impact on the development of PARP-centred therapies.
Assuntos
Linfoma de Células T/genética , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerases/genética , Linfócitos T/imunologia , Animais , Morte Celular , Células Cultivadas , Dano ao DNA , Linfoma de Células T/imunologia , Linfoma de Células T/patologia , Camundongos , Poli(ADP-Ribose) Polimerase-1/deficiência , Poli(ADP-Ribose) Polimerases/deficiênciaRESUMO
The plasminogen activator receptor (uPAR) is required for lung infiltration by innate immune cells in respiratory bacterial infections. In order to verify if this held true for respiratory viruses, wild type (WT) and uPAR knockout (uPAR(-/-)) mice were inoculated intranasally with the human respiratory syncytial virus (HRSV) and the influenza A virus. At several days post-infection (dpi), viral titers in the lungs were determined while cell infiltrates in the bronchoalveolar lavage (BAL) were analyzed by flow cytometry. In the case of influenza A, body weight loss and mortality were also monitored. Only minor differences were observed between infected WT and uPAR(-/-) mice, primarily in influenza virus replication and pathology. These results indicate that uPAR does not play a major role in limiting virus replication or in orchestrating the innate immune response against HRSV or influenza infections in mice. This suggests that there are fundamental differences in the immune control of the viral infections studied here and those caused by bacteria.
Assuntos
Receptores de Ativador de Plasminogênio Tipo Uroquinase/deficiência , Infecções Respiratórias/imunologia , Infecções Respiratórias/virologia , Ativador de Plasminogênio Tipo Uroquinase/deficiência , Animais , Feminino , Humanos , Imunidade Inata/imunologia , Vírus da Influenza A/imunologia , Vírus da Influenza A/patogenicidade , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Ativador de Plasminogênio Tipo Uroquinase/imunologia , Vírus Sincicial Respiratório Humano/imunologia , Vírus Sincicial Respiratório Humano/patogenicidade , Análise de Sobrevida , Ativador de Plasminogênio Tipo Uroquinase/imunologia , Carga Viral , Replicação Viral/fisiologiaRESUMO
Major histocompatibility complex class I proteins (MHC-I) load short peptides derived from proteolytic cleavage of endogenous proteins in any cell of the body, in a process termed antigen processing and presentation. When the source proteins are altered self or encoded by a pathogen, recognition of peptide/MHC-I complexes at the plasma membrane leads to CD8(+) T-lymphocyte responses that clear infections and probably underlie tumor immune surveillance. On the other hand, presentation of self peptides may cause some types of autoimmunity. The peptides that are presented determine the specificity and efficiency of pathogen clearance or, conversely, of immunopathology. In this review we highlight the growing number of peptidases which, as a by-product of their regular activity, can generate peptide epitopes for immune surveillance. These â¼20 peptidases collectively behave as a guerrilla army partnering with the regular proteasome army in generating a variety of peptides for presentation by MHC-I and thus optimally signaling infection.
Assuntos
Aminopeptidases/metabolismo , Apresentação de Antígeno/genética , Células Dendríticas/enzimologia , Endopeptidases/metabolismo , Exopeptidases/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Aminopeptidases/imunologia , Citosol/imunologia , Citosol/metabolismo , Células Dendríticas/citologia , Células Dendríticas/imunologia , Endopeptidases/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Exopeptidases/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Peptídeos/imunologia , Peptídeos/metabolismo , Fagossomos/genética , Fagossomos/imunologia , Complexo de Endopeptidases do Proteassoma/imunologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Linfócitos T Citotóxicos/citologia , Linfócitos T Citotóxicos/imunologiaRESUMO
CD8(+) T cells identify and kill infected cells through the specific recognition of short viral antigens bound to human major histocompatibility complex (HLA) class I molecules. The colossal number of polymorphisms in HLA molecules makes it essential to characterize the antigen-presenting properties common to large HLA families or supertypes. In this context, the HLA-B*27 family comprising at least 100 different alleles, some of them widely distributed in the human population, is involved in the cellular immune response against pathogens and also associated to autoimmune spondyloarthritis being thus a relevant target of study. To this end, HLA binding assays performed using nine HLA-B*2705-restricted ligands endogenously processed and presented in virus-infected cells revealed a common minimal peptide motif for efficient binding to the HLA-B*27 family. The motif was independently confirmed using four unrelated peptides. This experimental approach, which could be easily transferred to other HLA class I families and supertypes, has implications for the validation of new bioinformatics tools in the functional clustering of HLA molecules, for the identification of antiviral cytotoxic T lymphocyte responses, and for future vaccine development.
Assuntos
Antígenos Virais/metabolismo , Antígeno HLA-B27/metabolismo , Proteínas Virais/metabolismo , Motivos de Aminoácidos , Animais , Apresentação de Antígeno , Antígenos Virais/imunologia , Linhagem Celular , Antígeno HLA-B27/química , Humanos , Ligantes , Camundongos , Ligação Proteica , Estabilidade Proteica , Vírus Sincicial Respiratório Humano/imunologia , Proteínas Virais/imunologiaRESUMO
Signals from the TCR that specifically contribute to effector versus memory CD8⺠T cell differentiation are poorly understood. Using mice and adoptively transferred T lymphocytes lacking the small GTPase N-ras, we found that N-ras-deficient CD8⺠T cells differentiate efficiently into antiviral primary effectors but have a severe defect in generating protective memory cells. This defect was rescued, although only partly, by rapamycin-mediated inhibition of mammalian target of rapamycin (mTOR) in vivo. The memory defect correlated with a marked impairment in vitro and in vivo of the antigen-mediated early induction of T-box transcription factor Eomesodermin (Eomes), whereas T-bet was unaffected. Besides N-ras, early Eomes induction in vitro required phosphoinositide 3-kinase (PI3K)-AKT but not extracellular signal-regulated kinase (ERK) activation, and it was largely insensitive to rapamycin. Consistent with N-ras coupling Eomes to T cell memory, retrovirally enforced expression of Eomes in N-ras-deficient CD8⺠T cells effectively rescued their memory differentiation. Thus, our study identifies a critical role for N-ras as a TCR-proximal regulator of Eomes for early determination of the CD8⺠T cell memory fate.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Proteínas Proto-Oncogênicas p21(ras)/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas com Domínio T/imunologia , Animais , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/imunologia , Memória Imunológica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteínas Proto-Oncogênicas p21(ras)/deficiência , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas com Domínio T/biossíntese , Proteínas com Domínio T/genéticaRESUMO
INTRODUCTION: Human immunodeficiency virus type 1 (HIV-1) dual infection (DI) in long-term nonprogressor-elite controller patients (LTNP-EC) has been described only in sporadic cases and then, consequences in disease progression are not clearly established. To fill-up this limited knowledge, we analyzed, for the first time, the prevalence, host genetic polymorphisms, and clinical consequences of HIV-1 DI in a group of LTNP-EC. METHODS: For DI detection, nucleotide sequences in env gene from viruses from 20 LTNP-EC were analyzed by maximum likelihood. Epidemiological and clinical parameters and host factors of patients were also studied. RESULTS: DI was detected in 4 (20%) of the 20 LTNP-EC, of which 3 maintained the elite controller status. CD4⺠T-cell counts were not different between single and DI patients although higher CD8⺠T-cell counts were observed in DI patients, and, consequently, the CD4âº/CD8⺠ratios were lower in LTNP-EC DI patients. CONCLUSIONS: Prevalence of HIV-1 DIs in LTNP-EC is similar to other groups of HIV-1 patients; in addition, DI was not associated with loss of disease control in the patients. These DI LTNP-EC patients showed, in comparison with single infected patients, higher numbers of CD8⺠T cells and lower CD4âº/CD8⺠ratios.
Assuntos
Coinfecção , Sobreviventes de Longo Prazo ao HIV , HIV-1 , Antígenos HLA-B/imunologia , Imunidade Inata/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Adulto , Sequência de Bases , Contagem de Linfócito CD4 , Relação CD4-CD8 , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Coinfecção/imunologia , Progressão da Doença , Feminino , Seguimentos , HIV-1/imunologia , Humanos , Imunidade Inata/genética , Masculino , Pessoa de Meia-Idade , Filogenia , Prevalência , Espanha/epidemiologia , Carga Viral , Replicação ViralRESUMO
Recognition of infected or altered cells by CD8(+) cytotoxic T lymphocytes is mediated by direct interaction of their T-cell receptor with peptides presented by MHC class I molecules. Peptides are transferred for assembly with newly synthesized MHC molecules by the transporters associated with antigen processing (TAP). Yet, a fraction of described epitopes are presented independently of TAP. Current belief is that most of them derive from membrane proteins, mostly from their signal sequences, and are processed by vesicular proteases. A thorough review of the published data may challenge some of these views.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Apresentação de Antígeno , Antígenos de Histocompatibilidade Classe I/imunologia , Linfócitos T CD8-Positivos/imunologia , Citosol/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Proteínas de Membrana/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de SinaisRESUMO
Respiratory syncytial virus causes lower respiratory tract infections in infancy and old age, affecting also immunocompromised patients. The viral fusion protein is an important vaccine candidate eliciting antibody and cell-mediated immune responses. CD8(+) cytotoxic T lymphocytes (CTLs) are known to have a role in both lung pathology and viral clearance. In BALB/c mice, the fusion protein epitope F249-258 is presented to CTLs by the murine major histocompatibility complex (MHC) class I molecule K(d). In cells infected with recombinant vaccinia viruses encoding the fusion protein, F249-258 is presented by MHC class I molecules through pathways that are independent of the transporters associated with antigen processing (TAP). We have now found that F249-258 can be generated from non-infectious virus from an exogenous source. Antigen processing follows a lysosomal pathway that appears to require autophagy. As a practical consequence, inactivated virus suffices for in vivo priming of virus-specific CTLs.
Assuntos
Apresentação de Antígeno , Epitopos de Linfócito T/imunologia , Lisossomos/metabolismo , Infecções por Vírus Respiratório Sincicial/imunologia , Vírus Sinciciais Respiratórios/imunologia , Linfócitos T Citotóxicos/imunologia , Vacinas Virais/imunologia , Idoso , Animais , Antígenos Ly/metabolismo , Antígenos Virais/genética , Antígenos Virais/imunologia , Autofagia , Linhagem Celular , Epitopos de Linfócito T/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Hospedeiro Imunocomprometido , Lactente , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Vírus Sinciciais Respiratórios/metabolismo , Linfócitos T Citotóxicos/virologiaRESUMO
Toll-like receptors (TLRs) engage networks of transcriptional regulators to induce genes essential for antimicrobial immunity. We report that NFAT5, previously characterized as an osmostress responsive factor, regulates the expression of multiple TLR-induced genes in macrophages independently of osmotic stress. NFAT5 was essential for the induction of the key antimicrobial gene Nos2 (inducible nitric oxide synthase [iNOS]) in response to low and high doses of TLR agonists but is required for Tnf and Il6 mainly under mild stimulatory conditions, indicating that NFAT5 could regulate specific gene patterns depending on pathogen burden intensity. NFAT5 exhibited two modes of association with target genes, as it was constitutively bound to Tnf and other genes regardless of TLR stimulation, whereas its recruitment to Nos2 or Il6 required TLR activation. Further analysis revealed that TLR-induced recruitment of NFAT5 to Nos2 was dependent on inhibitor of κB kinase (IKK) ß activity and de novo protein synthesis, and was sensitive to histone deacetylases. In vivo, NFAT5 was necessary for effective immunity against Leishmania major, a parasite whose clearance requires TLRs and iNOS expression in macrophages. These findings identify NFAT5 as a novel regulator of mammalian anti-pathogen responses.
Assuntos
Regulação da Expressão Gênica/imunologia , Redes Reguladoras de Genes/imunologia , Macrófagos/metabolismo , Receptores Toll-Like/metabolismo , Fatores de Transcrição/metabolismo , Animais , Imunoprecipitação da Cromatina , Primers do DNA/genética , Citometria de Fluxo , Regulação da Expressão Gênica/genética , Redes Reguladoras de Genes/genética , Quinase I-kappa B/metabolismo , Immunoblotting , Interleucina-6/metabolismo , Leishmania/imunologia , Luciferases , Camundongos , Camundongos Knockout , Análise em Microsséries , Óxido Nítrico Sintase Tipo II/metabolismo , Nitritos/metabolismo , Plasmídeos/genética , Fatores de Transcrição/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Susceptibility to HIV infection and disease progression are complex traits modulated by environmental and genetic factors, affecting innate and adaptive immune responses, among other cellular processes. A single nucleotide polymorphism (SNP) 35 kb upstream of the HLA-C gene locus (-35C/T) was previously shown to correlate with increased HLA-C expression and improved control of HIV-1. Here, we genotyped the -35C/T SNP in 639 subjects (180 uninfected patients, 304 HIV progressors and 155 LTNP) and confirmed the association of the -35C/T variant with the LTNP phenotype. The genotype frequencies in the general population subjects did not differ significantly from those seen in HIV progressors (p-value=0.472). However, a significant higher frequency of the protective CC genotype was identified when LTNP were compared either with HIV progressors alone (p-value<0.0001) or progressors and uninfected subjects together (p-value<0.0001). When considering aviremic LTNP alone (elite controllers; viral load below 50 copies/ml), the -35 CC genotype was not overrepresented compared to HIV progressors. Conversely, a significant association was found with the viremic LTNP groups (viral loads below 10,000 copies/ml). These results suggest that other factors alone or in combination with the -35 CC genotype may play an important role in differentiating the elite controller status from LTNP. Combination of different genetic variants may have additive or epistatic effects determining the HIV course of infection.
Assuntos
Genótipo , Infecções por HIV/genética , Infecções por HIV/imunologia , Sobreviventes de Longo Prazo ao HIV , Antígenos HLA-C/genética , Viremia/genética , Viremia/imunologia , Alelos , Infecções por HIV/virologia , Humanos , Fenótipo , Polimorfismo de Nucleotídeo Único , Viremia/virologiaRESUMO
The generation of peptides presented by MHC class I molecules requires the proteolytic activity of the proteasome and/or other peptidases. The processing of a short vaccinia virus-encoded antigen can take place by a proteasome-independent pathway involving initiator caspase-5 and -10, which generate antigenic peptides recognized by CD8(+) T lymphocytes. In the present study, comparing single versus double enzyme digestions by mass spectrometry analysis, both qualitative and quantitative differences in the products obtained were identified. These in vitro data suggest that each enzyme can use the degradation products of the other as substrate for new cleavages, indicating concerted endoproteolytic activity of caspase-5 and -10.