Immunoglobulin V _H 3 Gene Products: Natural Ligands for HIV gp120

Abstract

Infection with human immunodeficiency virus-type 1 (HIV-1) depletes T cells expressing CD4 and B cells expressing immunoglobulin (Ig) VH3 gene products. A subpopulation of normal B cells from non-HIV-infected individuals was shown to bind to HIV gp120 by means of membrane Ig; most of these B cells expressed VH3 family Ig. Serum VH3 IgM from uninfected individuals also avidly bound gp120. Finally, gp120 selectively induced Ig secretion by VH3 B cells, indicating that the binding of gp120 functionally activated these cells. These results indicate that naturally occurring VH3 Ig is a second ligand for gp120 and a candidate superantigen for VH3 B cells.