INTERACTIVE LASER CYTOMETRIC ANALYSIS OF RETROVIRAL PROTEIN EXPRESSION IN HIV-INFECTED LYMPHOCYTIC CELL-LINES

We have used interactive laser cytometry to investigate the expression of human immunodeficiency virus (HIV) envelope glycoproteins gp160,gp41,gp120, and the core protein p24 in the HIV-infected human lymphocyte cell lines H-9, CEM-SS, and C8166. This method allowed for the ultrasensitive detection of fluorescence signals at the single cell level and, when combined with specific anti-HIV antibodies, permitted unique quantitative detection of HIV antigens. Indirect immunofluorescence assays with monoclonal antibodies directed against gp120 revealed that a large proportion of lymphocytic cells expressed increased gp120-associated fluorescence consistent with HTLV-IIIRF infection. Certain monoclonal and polyclonal antibodies were also effective in quantifying gp160, gp41, and p24 expression. Expression of these antigens was found to vary significantly within 48 h. Significant loss (≥ 50%) of gp120 expression was observed when cells were treated with 1.0 μM AZT. The expression of the HIV-associated protein markers gp160, gp41, and p24 was detectable 24 h after infection of C8166, a cord blood lymphocytic cell line. C8166 cells expressed an additional 6- to 10-fold increase in gp120 in 48 h as well as a 3- to 4-fold increase in gp160, gp41, and p24. AZT (0.01 and 0.1 μM) decreased the expression of gp120, gp160, and p24 in a dose-dependent fashion. This new application of interactive laser cytometry permits early, sensitive, and statistically based distinctions in the expression of HIV-associated antigens in infected target cells at the single-cell level, and allows detection of important changes in HIV-associated antigen expression and the kinectics thereof. This technololgy may thereby provide a powerful new tool for investigations of HIV biology as well as facilitate the discovery and characterization of novel antiviral agents. © 1990, Mary Ann Liebert, Inc. All rights reserved.