RESUMEN
DNA sequence-based typing at the HLA-A, -B, -C, -DPB1, -DQA1, -DQB1, and -DRB1 loci was performed on anonymized samples provided by 339 healthy adult blood bank donors in Managua, Nicaragua. The purpose of the study was to characterize allele frequencies in the local population to support studies of T cell immunity against pathogens, including Dengue virus. Deviations from Hardy Weinberg proportions were detected for all class II loci (HLA-DPB1, -DQA1, -DQB1 and -DRB1), and at the class I C locus, but not at the class I A and B loci. The genotype data will be available in the Allele Frequencies Net Database.
Asunto(s)
Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Antígenos HLA-DP/genética , Antígenos HLA-DQ/genética , Antígenos HLA-DR/genética , Adulto , Bases de Datos Genéticas , Dengue/inmunología , Frecuencia de los Genes , Genética de Población , Genotipo , Prueba de Histocompatibilidad , Humanos , Desequilibrio de Ligamiento , Nicaragua , Análisis de Secuencia de ADN , Linfocitos T/inmunologíaRESUMEN
Brucella melitensis, one of the causative agents of human brucellosis, causes acute, chronic, and relapsing infection. While T cell immunity in brucellosis has been extensively studied in mice, no recognized human T cell epitopes that might provide new approaches to classifying and prognosticating B. melitensis infection have ever been delineated. Twenty-seven pools of 500 major histocompatibility complex class II (MHC-II) restricted peptides were created by computational prediction of promiscuous MHC-II CD4(+) T cell derived from the top 50 proteins recognized by IgG in human sera on a genome level B. melitensis protein microarray. Gamma interferon (IFN-γ) and interleukin-5 (IL-5) enzyme-linked immunospot (ELISPOT) analyses were used to quantify and compare Th1 and Th2 responses of leukapheresis-obtained peripheral blood mononuclear cells from Peruvian subjects cured after acute infection (n = 9) and from patients who relapsed (n = 5). Four peptide epitopes derived from 3 B. melitensis proteins (BMEI 1330, a DegP/HtrA protease; BMEII 0029, type IV secretion system component VirB5; and BMEII 0691, a predicted periplasmic binding protein of a peptide transport system) were found repeatedly to produce significant IFN-γ ELISPOT responses in both acute-infection and relapsing patients; none of the peptides distinguished the patient groups. IL-5 responses against the panel of peptides were insignificant. These experiments are the first to systematically identify B. melitensis MHC-II-restricted CD4(+) T cell epitopes recognized by the human immune response, with the potential for new approaches to brucellosis diagnostics and understanding the immunopathogenesis related to this intracellular pathogen.