DEVELOPMENT OF T-CELL LINES EXPRESSING FUNCTIONAL HIV-1 ENVELOPE GLYCOPROTEINS FOR EVALUATION OF IMMUNE-RESPONSES IN HIV-INFECTED INDIVIDUALS

The human T-lymphoid cell line, GEM, was transfected with gp160 cDNA o f human immunodeficiency virus type 1 (HIV-1)(pm213). Three clones exp ressing the envelope glycoproteins (env), designated CEM-213env1, -env 4, and -env7, were isolated. These clones expressed high levels of sur face gp41 and gp120, as demonstrated by flow cytometry with anti-HIV e nv monoclonal antibodies. Processing and function of env was shown by induction of syncytia with CD4-expressing HeLa cells and by immunoblot analysis. The env expression resulted in specific down-regulation of surface CD4 levels, supporting the role of HIV env in CD4 modulation. Furthermore, serum samples from nine of nine HIV-1-infected individual s bound specifically to the env-expressing transfectants, substantiati ng the presence of conserved antigenic determinants. These sera also m ediated antibody-dependent cellular cytotoxicity (ADCC) of the env-exp ressing cell lines. The env-expressing cell lines provide a relevant, safe, and practical model for qualitative and quantitative analysis of humoral and cellular immune responses and their role in HIV-1 pathoge nesis and therapy.