Cytotoxic T-lymphocytes that kill autologous CD4+ lymphocytes are associated with CD4+ lymphocyte depletion in HIV-1 infection
Grant, M.D.; Smail, F.M.; Rosenthal, K.L.
Journal of Acquired Immune Deficiency Syndromes 7(6): 571-579
1994
ISSN/ISBN: 0894-9255 PMID: 7909845 Document Number: 431204
Human immunodeficiency virus type 1 (HIV-1)-infected individuals, but not HIV-seronegative controls, have non-HLA-restricted T-cell receptor alpha-beta+ CD8+ cytotoxic T-lymphocytes (CTL) that kill activated uninfected CD4+ lymphocytes. In vitro stimulation of peripheral blood mononuclear cells from HIV-1-infected individuals with concanavalin A (Con A) or by coculture with phytohemagglutinin-activated autologous lymphoblasts induced CTL that killed autologous and heterologous CD4+ lymphocytes, but not Con A-activated CD8+ lymphocytes or Epstein-Barr virus (EBV)-transformed B lymphocytes. EBV did not stimulate such CTL in two subjects tested, although stimulation with Con A or autologous lymphoblasts induced CTL activity against CD4+ lymphocytes in both subjects. CTL activity against autologous CD4+ lymphocytes varied over time; killing of heterologous CD4+ lymphocytes was often higher than that of autologous CD4+ lymphocytes. HIV-infected individuals with Con A-inducible CTL against autologous CD4+ lymphocytes lost more CD4+ lymphocytes within 6 months of testing than HIV-infected individuals with no such CTL (p lt .01). The mean (+- SD) decrease in CD4+ lymphocyte counts in a group of HIV-infected individuals with CTL activity against autologous CD4+ lymphocytes was 121 +- 84, or 36%, of total CD4+ lymphocytes over 6 months. In contrast, there was no significant change in mean CD4+ lymphocyte count over 6 months in a group of HIV-infected individuals without CTL activity against autologous CD4+ lymphocytes. In some HIV-infected individuals, CTL activity against autologous CD4+ lymphocytes fell coincident with a drop in CD4+ lymphocyte number in vivo. The same individuals maintained CTL activity against CD4+ lymphocytes from an uninfected individual, consistent with elimination of autologous CD4+ targets of CTL from the HIV-infected individuals in vivo. These results suggest that CTL against CD4+ lymphocytes contribute to CD4+ lymphocyte loss in HIV infection.