Human CD4+ T lymphoblastoid Jurkat cells were stably transfected with two different plasmid vectors containing the cDNA of human immunodeficiency virus-type 1 (HIV-1) tat gene under the control of either the promoter of simian virus 40 (pRPneo/tat) or the long terminal repeat region of SL3 murine leukaemia virus (pRPneo/SL3/tat). Both pRPneo/tat and pRPneo/SL3/tat Jurkat cell lines showed a constant and high production of bioactive Tat in transient co-transfection assays with an HIV-1 long terminal repeat (LTR)-chloramphenicol acetyltransferase (CAT) reporter plasmid. Tat-positive and mock-transfected Jurkat cells were cultured with various cytotoxic agents, which have been associated to the progressive loss of CD4 T-lymphocytes characteristic of HIV-1 disease. In the presence of recombinant tumour necrosis factor-alpha (TNF-alpha), anti-fas antibody, Leu3a anti-CD4 antibody, the percentage of apoptosis, evaluated in a 24-72 h short-term assay, was lower (P < 0.05) in tat-positive Jurkat cells than in mock-transfected controls. The low susceptibility to the cytotoxic activity of TNF-alpha and anti-fas antibody of tat-transfected cells was confirmed by counting viable cells up to 15 d of culture. Also, recombinant Tat protein was able to prevent the increase of apoptosis induced in mock-transfected Jurkat by TNF-alpha. Of note, tat-expressing cells showed a better survival with respect to mock-transfected control cells even when acutely infected with high doses (500,000 cpm of reverse transcriptase) of HIV-1 (strain IIIB) or treated with heat-inactivated HIV-1. These data demonstrate that the expression of the regulatory HIV-1 Tat protein is able to rescue Jurkat lymphoblastoid cells from apoptosis induced by a variety of cytotoxic agents. Since Tat protein expression is restricted to the initial phases of an active HIV-1 replication, the anti-apoptotic effect of Tat could have the physiological significance of selectively protecting HIV-1 producing cells from death, at least for the time necessary to allow virus production and spreading.

Tat?expressing Jurkat cells show an increased resistance to different apoptotic stimuli, including acute human immunodeficiency virus?type 1 (HIV ?1) infection

D Gibellini;
1995

Abstract

Human CD4+ T lymphoblastoid Jurkat cells were stably transfected with two different plasmid vectors containing the cDNA of human immunodeficiency virus-type 1 (HIV-1) tat gene under the control of either the promoter of simian virus 40 (pRPneo/tat) or the long terminal repeat region of SL3 murine leukaemia virus (pRPneo/SL3/tat). Both pRPneo/tat and pRPneo/SL3/tat Jurkat cell lines showed a constant and high production of bioactive Tat in transient co-transfection assays with an HIV-1 long terminal repeat (LTR)-chloramphenicol acetyltransferase (CAT) reporter plasmid. Tat-positive and mock-transfected Jurkat cells were cultured with various cytotoxic agents, which have been associated to the progressive loss of CD4 T-lymphocytes characteristic of HIV-1 disease. In the presence of recombinant tumour necrosis factor-alpha (TNF-alpha), anti-fas antibody, Leu3a anti-CD4 antibody, the percentage of apoptosis, evaluated in a 24-72 h short-term assay, was lower (P < 0.05) in tat-positive Jurkat cells than in mock-transfected controls. The low susceptibility to the cytotoxic activity of TNF-alpha and anti-fas antibody of tat-transfected cells was confirmed by counting viable cells up to 15 d of culture. Also, recombinant Tat protein was able to prevent the increase of apoptosis induced in mock-transfected Jurkat by TNF-alpha. Of note, tat-expressing cells showed a better survival with respect to mock-transfected control cells even when acutely infected with high doses (500,000 cpm of reverse transcriptase) of HIV-1 (strain IIIB) or treated with heat-inactivated HIV-1. These data demonstrate that the expression of the regulatory HIV-1 Tat protein is able to rescue Jurkat lymphoblastoid cells from apoptosis induced by a variety of cytotoxic agents. Since Tat protein expression is restricted to the initial phases of an active HIV-1 replication, the anti-apoptotic effect of Tat could have the physiological significance of selectively protecting HIV-1 producing cells from death, at least for the time necessary to allow virus production and spreading.
tat, apoptotic, HIV-1
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1078939
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