ENVELOPE GLYCOPROTEINS OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 - PROFOUND INFLUENCES ON IMMUNE FUNCTIONS

Infection by human immunodeficiency virus type 1 (HIV-1) lends to prog ressive destruction of the CD4(+) T-cell subset, resulting in immune d eficiency and RIDS. The specific binding of the viral external envelop e glycoprotein of HIV-1, gp120, to the CD4 molecules initiates viral e ntry. In the past few years, several studies have indicated that the i nteraction of HN-I envelope glycoprotein with cells and molecules of t he immune system leads to pleiotropic biological effects on immune fun ctions, which include effects on differentiation of CD34(+) lymphoid p rogenitor cells and thymocytes, aberrant activation and cytokine secre tion patterns of mature T cells, induction of apoptosis, B-cell hypera ctivity, inhibition of T-cell-dependent B-cell differentiation, modula tion of macrophage functions, interactions with components of compleme nt, and effects on neuronal cells. The amino acid sequence homologies of the envelope glycoproteins with several cellular proteins have sugg ested that molecular mimicry may play a role in the pathogenesis of th e disease. This review summarizes work done by several investigators d emonstrating the profound biological effects of envelope glycoproteins of HIV-1 on immune system cells. Extensive studies have also been don e on interactions of the viral envelope proteins with components of th e immune system which may be important eliciting a ''protective immune response.'' Understanding the influences of HIV-1 envelope glycoprote ins on the immune system may provide valuable insights into HIV-1 dise ase pathogenesis and carries implications for the trials of HIV-1 enve lope protein vaccines and immunotherapeutics.