title: Brucella melitensis T cell epitope recognition in humans with brucellosis in Peru.
abstract: 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.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of California-San Diego, La Jolla, California, USA.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Cannella
authors.forename: Cecilia S Lindestam
authors.initials: CS
authors.lastname: Arlehamn
authors.forename: John
authors.initials: J
authors.lastname: Sidney
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Patra
authors.forename: Katherine
authors.initials: K
authors.lastname: Torres
authors.forename: Renee M
authors.initials: RM
authors.lastname: Tsolis
authors.forename: Li
authors.initials: L
authors.lastname: Liang
authors.forename: Philip L
authors.initials: PL
authors.lastname: Felgner
authors.forename: Mayuko
authors.initials: M
authors.lastname: Saito
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gotuzzo
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sette
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Vinetz
mesh_terms: D000208:Acute Disease; D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis; D017347:Brucella melitensis / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002908:Chronic Disease; D015331:Cohort Studies; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D046228:Microarray Analysis / Q000379:methods; D010568:Peru
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D015848:Interleukin-5; D007371:Interferon-gamma