1318. Brucella melitensis T cell Epitope Recognition by Humans Recovered From Brucellosis in Peru
Session: Poster Abstract Session: Biomarkers and Correlates of Protection
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • apc_pres_11in.pdf (4.8 MB)
  • Background: B. melitensis infection may relapse despite appropriate antibiotic therapy. While T cell immunity in brucellosis has been studied in mice, no T cell epitopes recognized by humans have been delineated. 

    Methods: Twenty-seven pools of 500 MHC-II restricted peptides were created by computational prediction of promiscuous CD4+ T cell derived from the top 50 proteins recognized by human sera on a genome-level B. melitensis protein microarray. Interferon-g(IFN-g) and Interleukin-5 (IL-5) ELISPOT analyses were used to quantify TH1 vs. TH2 responses of leukapheresis-obtained peripheral blood mononuclear cells from patients cured after acute infection (N=9) vs. patients who relapsed (N=5).

    Results: Four peptide epitopes derived from 3 B. melitensis proteins (BMEI1330, DegP/HtrA protease; BMEII0029, Type IV secretion system component VirB5; BMEII0691,predicted periplasmic binding protein of a peptide transport system) were found repeatedly to produce significant IFN-g ELISPOT responses in both acute and relapsing patients; none of the peptides distinguished the patient groups. IL-5 responses against the panel of peptides were insignificant, suggesting a lack of significant TH2 response to the 50-most recognized proteins in the B. melitensis genome.

    Conclusion: These experiments are the first to systematically identify B. melitensis peptide epitopes recognized by the human immune response, with the potential for new approaches to brucellosis diagnostics.

    Anthony Cannella, M.D., Medicine/Infectious Diseases, University of California, San Diego, San Diego, CA, Cecilia Lindestam-Arlehamn, Ph.D., Infectious Diseases, La Jolla Institute for Allergy & Immunology, La Jolla (San Diego, CA, Kailash Patra, Ph.D., Medicine; Infectious Diseases, University of California, San Diego, La Jolla (San Diego), CA, Katherine Torres, M.S., Tropical Medicine, Universidad Peruana Cayetano Heredia, San Martin de Porres Lima, Peru, John Sidney, Ph.D., Infectious Diseases, La Jolla Institue of Allergy and Immunology, La Jolla (San Diego, CA, Renee Tsolis, Ph.D., Medicine/Infectious Diseases, University of California, Davis, Davis, CA, Li Liang, Ph.D., Medicine/Infectious Diseases, University of California, Irvine, irvine, CA, Philip Felgner, Ph.D., Medicine/Infectious Diseases, University of California, Irvine, Irvine, CA, Mayuko Saito, M.D., Ph.D., Medicine/Infectious Diseases, University of California, San Diego, La Jolla (San Diego), CA, Eduardo Gotuzzo, MD, Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru, Robert Gilman, MD, DTMH, Johns Hopkins Bloomberg School of Public Health, Asociación Benéfica PRISMA, Universidad Peruana Cayetano Heredia, Lima, Peru, Alessandro Sette, PhD, La Jolla Institute for Allergy and Immunology, San Diego, CA and Joseph Vinetz, MD, FIDSA, Medicine, University of California San Diego, La Jolla, CA

    Disclosures:

    A. Cannella, None

    C. Lindestam-Arlehamn, None

    K. Patra, None

    K. Torres, None

    J. Sidney, None

    R. Tsolis, None

    L. Liang, None

    P. Felgner, None

    M. Saito, None

    E. Gotuzzo, None

    R. Gilman, None

    A. Sette, None

    J. Vinetz, None

    Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.