ANTIBODY-DIRECTED NATURAL CYTOTOXICITY RESULTS IN ENHANCED KILLING OFHIV GP120-COATED CEMNKR CELLS

Cellular cytotoxicity may be an important defense in the control of HI V progression. In the present study antibodies were attached to periph eral blood mononuclear cells (PBMC) by exposing them to polyethylene g lycol and phthalate oil in the presence of HIV human hyperimmune IVIG (HIVIG). The attachment procedure is known as ''franking'' and the res ultant cytotoxicity is termed ''antibody-directed.'' The majority of t he cells that are franked with attached HIVIG are CD16(+) (Fc gamma RI II), placing them in the natural killer cell population. Franking incr eased the cytotoxicity of PBMC from both healthy controls and HIV-sero positive patients approximately fourfold compared to conventional anti body-dependent cellular cytotoxicity using CEM cells coated with HIV g p120 antigen as targets. Use of anti-HIV monoclonal antibodies for fra nking was less efficient than polyclonal HIVIG. The HIVIG-franked PBMC suppressed p24 production of in vitro HIVIIIb-infected human PBMC. Th e ability of HIVIG to enhance and direct cytotoxicity to HIV targets m ay suggest a new therapeutic approach to HIV control. (C) 1997 Academi c Press.