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ABSTRACT: Indinavir (IDV) is a potent and selective human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) widely used in antiretroviral therapy for suppression of HIV, but its effects on the immune system are relatively unknown. Recently, it has been reported that PIs inhibit lymphocyte apoptosis. In the present study we have investigated the effects of ex vivo addition of IDV on lymphocyte activation and apoptosis in cells from HIV-infected children (n = 18) and from healthy uninfected individuals (controls, n = 5) as well as in Jurkat and PM1 T-cell lines. Pretreatment of control peripheral blood mononuclear cell (PBMC) cultures with IDV resulted in a dose-dependent inhibition of lymphoproliferative responses to different activation stimuli. Additionally, this treatment led to cell-cycle arrest in G0/G1 phase in anti-CD3 monoclonal antibody-stimulated PBMC cultures in controls and in 15 of 18 HIV-infected children. Spontaneous- or activation-induced apoptosis of PBMCs from HIV-infected or uninfected individuals or of Fas-induced apoptosis in Jurkat and PM1 T cell lines were not inhibited by IDV. Moreover, IDV did not inhibit activation of caspases-1, -3, -4, -5, -9, and -8 in lysates of Jurkat T cells undergoing Fas-induced apoptosis. The findings indicate that IDV interferes with cell-cycle progression in primary cells but does not directly affect apoptosis. It is concluded that IDV may prolong cell survival indirectly by inhibiting their entry into cell cycle. In individuals on PI therapy, PI-mediated effects could potentially modulate immunologic responses independently of antiviral activity against HIV.
Blood 08/2001; 98(2):383-9. · 9.90 Impact Factor
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ABSTRACT: Immune reconstitution after antiretroviral therapy in human immunodeficiency virus (HIV)infected patients may result from the recovery of thymus function, peripheral redistribution, or decreased T cell destruction. This study investigated levels of T cell receptor gene rearrangement excision circles (TRECs) as a measure of recent thymic emigrant cells in peripheral blood lymphocytes of 50 HIV-infected infants and children who were followed-up for 40 months after the start or change of antiretroviral therapy. At baseline, patients exhibited fewer TRECs than did uninfected control subjects. The increase in TRECs after antiretroviral therapy was greater in infants than in older HIV-infected children. Of interest, patients who demonstrated discordant responses (i.e., increased CD4 T cell counts without significant virologic suppression) also had substantial gains in TRECs. Furthermore, TRECs correlated positively with the number of CD4 and naive T cells and negatively with age and virus load. Measurement of TRECs may serve as a useful tool for evaluating immune reconstitution in HIV-infected children receiving antiretroviral therapy.
The Journal of Infectious Diseases 06/2001; 183(10):1445-54. · 6.41 Impact Factor
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ABSTRACT: To examine the influence of change in antiretroviral therapy (ART) on patterns of CD8 T cell clonal dominance in HIV-infected children. Design: Seventeen HIV-infected children with plasma virus loads between 3.1 and 5.7 log10 were investigated before and after changes in ART.
CDR3 spectratyping was performed in 22 T cell receptor (TCR) Vbeta subfamilies by multiplex polymerase chain reaction (PCR) in purified peripheral blood CD8 T cells in conjunction with CD4 cell counts, plasma HIV-RNA copies and lymphoproliferative assays (LPA).
CD8 T cell clonal dominance in two or more Vbeta families was present in eight out of 17 children. After a change in therapy, 13 patients (76%) acquired new clones whereas three patients (17.6%) showed a loss in CD8 cell clones. An increase in the numbers of dominant clones correlated with an increase in percentage CD4 cell counts (P < 0.001) and with improved LPA responses to tetanus (P < 0.05) and alloantigens (P < 0.01). CD4 cell increase was associated with an initial mean gain of 3.1+/-2.1 CD8 cell clones, independent of a virological response. A loss of CD8 cell clones or failure to achieve CD4 T cell increase was associated with failure to achieve virological suppression.
Children with chronic HIV infection manifest CD8 T cell clonal dominance, which appears to be dependent upon the adequacy of the CD4 cells. With optimization of therapy, a gain in clonal dominance is the predominant response, except in situations of failure to contain viral replication.
AIDS 10/2000; 14(15):2229-38. · 6.24 Impact Factor
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ABSTRACT: The study of apoptosis in relation to various human disease states, particularly HIV infection, has seen a tremendous increase in activity. In this article, values obtained by seven different assays, designed to quantify apoptosis and applicable to the study of HIV infection, are compared in two cell systems: (1) stimulus-induced apoptosis in Jurkat cells treated with anti-Fas antibody and (2) spontaneous apoptosis in PBMCs isolated from HIV-infected children. The methods used included measurement of cells with subdiploid DNA content, labeling of DNA strand breaks by the TUNEL reaction, annexin V surface labeling for the detection of exposed phosphatidylserine, cytoplasmic antigen labeling with the apoptosis-specific antibody Apo 2.7, detection of changes in flow cytometric light-scattering properties, trypan blue dye exclusion by light microscopy, and detection of changes in cellular chromatin by fluorescence microscopy. These methods produced well-correlated values in the Jurkat system, whereas the same set of methods produced more discrepant values in the PBMC analyses, especially in those patients with low CD4 counts. Specifically, our results showed that the trypan blue test was unacceptable for quantification of apoptosis during HIV infection, whereas TUNEL, of all the methods tested, showed excellent overall correlation in both cell systems, was highly specific, and matched microscopic observation of the cells. Although many of the methods were suited to the study of a homogeneous cell line, caution must be exercised when examining cell death in a heterogeneous cell mixture from an HIV-infected individual.
AIDS Research and Human Retroviruses 12/1998; 14(16):1413-22. · 2.25 Impact Factor
