title: A model for the selective loss of major histocompatibility complex self-restricted T cell immune responses during the development of acquired immune deficiency syndrome (AIDS).
abstract: Functional analyses of peripheral blood leukocytes (PBL) from high risk HTLV-III antibody-negative and antibody-positive donors, as well as from patients with acquired immune deficiency syndrome (AIDS), lymphadenopathy syndrome (LAS), and AIDS-related complex (ARC) were performed by the in vitro generation of cytotoxic T lymphocyte (CTL) and proliferative responses to the HLA self-restricted antigens of influenza virus (S + X) and to nonself restricted HLA alloantigens (ALLO). All 40 antibody-negative donors tested responded to both S + X and ALLO in the CTL response, whereas six of 14 antibody-positive, two of three LAS, four of five ARC, and seven of 17 AIDS patients exhibited a selective absence of CTL to S + X, but generated normal or elevated CTL responses to ALLO. Of the remaining 10 AIDS patients, nine did not respond to either S + X or ALLO, and one responded to both S + X and ALLO. A similar selective loss of the proliferative response to S + X was found. We also observed antibody-positive donors who initially generated CTL responses to S + X and ALLO, but lost the S + X response as a function of time. We were able to restore the selective loss of S + X CTL activity in vitro by the addition of IL 2 and, to some extent, by co-stimulation with S + X plus ALLO. Depletion of CD4+ T helper cells and removal of autologous antigen-presenting cells from the PBL of healthy antibody-negative donors indicated that distinct T helper cell subsets exist in human PBL, and that S + X responses must use a CD4+ T helper population, whereas ALLO responses can utilize an alternate CD4- T helper pathway. A model is presented indicating the selective depletion of CD4+ T helper function in the developmental stages of AIDS. The functional test for T helper activity to self restricted antigens may be the earliest indicator of immune functional loss in the development of AIDS, and may precede a reduction in the absolute number of CD4+ cells.
mesh_terms: D000386:AIDS-Related Complex / Q000276:immunology; D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000914:Antibodies, Viral / Q000032:analysis; D006678:HIV / Q000276:immunology; D015483:HIV Antibodies; D006680:HLA Antigens / Q000032:analysis; D006801:Humans; D007519:Isoantigens / Q000032:analysis; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D015483:HIV Antibodies; D006680:HLA Antigens; D007519:Isoantigens