@article{4cef5ede04d44a8794e2ff76c9e58803,
title = "Mycobacterium avium and purified protein derivative-specific cytotoxicity mediated by CD4+ lymphocytes from healthy HIV-seropositive and-seronegative individuals",
abstract = "HIV is the greatest single risk factor for the development of tuberculosis. Diseases caused by M. tuberculosis and mycobacteria are the most common opportunistic infections in HIV-infected persons, which may stem from a functional defect of the CD4+ T-cell-mediated killing of macrophages harboring mycobacteria. Our objective was to investigate the M.tuberculosis-and M. avium-specific cytotoxic capacity of T cells from healthy, bacille Calmette-Gu{\'e}rin-vaccinated, HIV-seropositive individuals. Blood mononuclear cells were obtained from 10 healthy HIV-seropositive and 10 healthy seronegative persons with no history of previous or active mycobacterial infection. Antigen-specific killing of macrophages presenting mycobacterial antigens (purified protein derivative or M. avium culture filtrate) was conducted. The phenotype of the killer cells was determined by a fluorescence-activated cell sorter after antigen stimulation and by using purified CD4+ and CD8+ cell subsets. Substantial, but reduced antigen-specific cytotoxicity was observed in patients with asymptomatic HIV infection. The immunological dysfunction leading to reduced cytotoxic activity in healthy HIV-seropositive subjects could not be explained by a defect in the cytotoxic capacity of the individual CD4+ lymphocyte after antigen stimulation, and it could not be explained by a reduction in the total number of CD4+ cells before antigen stimulation. The antigen-specific cytotoxic activity was, however, closely related to the ability of the CD4+ T cells to respond to mycobacterial antigens. The immunological dysfunction leading to reduced mycobacterial-specific cytotoxic activity in healthy HIV-seropositive subjects is caused either by a reduction in the number of antigen-responsive CD4+ T cells (memory) or by an impairment of their ability to respond to antigenic stimuli.",
keywords = "Adult, BCG Vaccine, CD4-CD8 Ratio, CD4-Positive T-Lymphocytes, CD8-Positive T-Lymphocytes, Cytotoxicity, Immunologic, Female, HIV Seronegativity, HIV Seropositivity, HIV-1, Humans, Immunologic Memory, Lymphocyte Activation, Macrophages, Male, Matched-Pair Analysis, Mycobacterium avium Complex, Mycobacterium tuberculosis, T-Lymphocyte Subsets, Tuberculin, Vaccination",
author = "P Ravn and Pedersen, {B K}",
year = "1996",
language = "English",
volume = "12",
pages = "433--41",
journal = "J Acquir Immune Defic Syndr Hum Retrovirol",
issn = "1077-9450",
publisher = "Lippincott Williams and Wilkins",
number = "5",
}