Human immunodeficiency virus type 1 protease inhibitor modulates activation of peripheral blood CD4(+) T cells and decreases their susceptibility to apoptosis in vitro and in vivo.
CD4(+) T cells from patients with human immunodeficiency virus (HIV) infection undergo apoptosis at an increased rate, which leads to their depletion during disease progression. Both the Fas-Receptor (Fas-R) and interleukin-1beta (IL-1beta)-converting enzyme (ICE; caspase 1) appear to play a role in the mechanism of apoptosis of CD4(+) lymphocytes. Although Fas-R is upregulated on both CD4(+) and CD8(+) cells in HIV-infected patients, results from our laboratory and others indicate that, in patients with advanced disease, CD4(+) cells preferentially express ICE. Protease inhibitors have successfully halted the progression of HIV disease and increased CD4(+) T counts. In this study, we examined the effect of protease inhibitors on Fas-R (CD95), ICE (caspase 1) expression, apoptosis, and cell death in CD4(+) T cells of (1) HIV-infected patients who were receiving protease inhibitors, and (2) normal and patient CD4(+) T cells cultured with a protease inhibitor in vitro. Fifteen patients with advanced HIV disease on treatment showed dramatically decreased CD4(+) T-cell ICE expression, diminished apoptosis, and increased numbers of CD4(+) cells within 6 weeks of institution of protease inhibitor therapy, and before down-modulation of Fas-R (CD95) expression was evident. To determine the role of HIV infection, we studied the effect of ritonavir, a protease inhibitor, on normal and patient cells in vitro. Stimulated and unstimulated normal CD4(+) T cells, cultured with protease inhibitor, demonstrated markedly decreased apoptosis and ICE expression (P =. 01). While Fas-R expression was not significantly altered during short-term culture by such treatment, Fas-Ligand (Fas-L) membrane expression of phytohemagglutinin (PHA)-stimulated blood lymphocytes was decreased by protease inhibitor. In the presence of ritonavir, CD4(+) T cells from HIV-infected patients showed similar changes in ICE intracellular levels without alteration of Fas expression. In conclusion, protease inhibitors appear to decrease CD4(+) T-cell ICE expression and apoptosis before they affect Fas-R expression in HIV-infected patients. This action was independent of HIV infection, as similar effects were seen in CD4(+) T cells from normal controls. Some of the benefit of protease inhibitors may be related to modification of programmed cell death, which increases CD4(+) T-cell number. Whether this is due to directly to the changes effected in the caspase system remains to be determined.
Sloand
E M
EM
National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Kumar
P N
PN
Kim
S
S
Chaudhuri
A
A
Weichold
F F
FF
Young
N S
NS
D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology* / Q000473:pathology; D020170:Caspase 1 / Q000276:immunology; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000473:pathology; D017320:HIV Protease Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D019438:Ritonavir / Q000494:pharmacology* / Q000627:therapeutic use; D019014:fas Receptor / Q000276:immunology
D017320:HIV Protease Inhibitors; D019014:fas Receptor; D020170:Caspase 1; D019438:Ritonavir