Inhibition of antigen-induced lymphocyte proliferation by Tat protein from HIV-1

Raphael P. Viscidi, Kumudini Mayur, Howard M. Lederman, Alan D. Frankel

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306 Scopus citations


The purified human immunodeficiency virus type-1 (HIV-1) Tat protein inhibited lymphocyte proliferation induced by tetanus toxoid or Candida antigens by 66 to 97% at nanomolar concentrations of Tat. In contrast, Tat did not cause a significant reduction of lymphocyte proliferation in response to mitogens such as phytohemagglutinin or pokeweed mitogen. Inhibition was blocked by oxidation of the cysteine-rich region of Tat or by incubation with an antibody to Tat before the assay. A synthetic Tat peptide (residues 1 to 58) also inhibited antigen-stimulated proliferation. Experiments with H9 and U937 cell lines showed that Tat can easily enter both lymphocytes and monocytes. The specific inhibition of antigen-induced lymphocyte proliferation by Tat mimics the effect seen with lymphocytes from HIV-infected individuals and suggests that Tat might directly contribute to the immunosuppression associated with HIV infection.

Original languageEnglish (US)
Pages (from-to)1606-1608
Number of pages3
Issue number4937
StatePublished - 1989

ASJC Scopus subject areas

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