A review of HIV-1 Tat protein biological effects.

The authors have reviewed some biological properties of HIV-1 Tat protein, and have also reported some personal data. This viral regulatory protein is endowed with multifunctional activities, acting as an endogenous factor in the infected cells and exogenously, on those uninfected. In particular, Tat-induced proliferation and differentiation of HIV target cells which promotes viral infection, is discussed in this review. However, exogenous Tat protein can sometimes also produce, directly or indirectly, damaging effects in different organs and host systems, such as myocardium, kidney, liver and central nervous system (CNS). For example some data also demonstrate an increase in the apoptotic index induced by Tat at various levels, including the immune system. The effective role of HIV-1 Tat protein in promoting viral replication and its high immunogenicity suggest useful employment of this protein for therapeutic or preventive vaccine preparations. Copyright 2004 John Wiley & Sons, Ltd.