Quantitative analysis of AIDS-related virus-carrying cells by plaque-forming assay using an HTLV-I-positive MT-4 cell line.

Quantitation of acquired immune deficiency syndrome (AIDS)-related virus-bearing cells was analyzed by a newly developed plaque-forming assay. A chemically adherent HTLV-I-positive MT-4 cell monolayer was used as the cytolytic responder cells to the AIDS-virus infection. When AIDS-virus-infected cells (Molt-4/HTLV-III, H9/HTLV-III, and CEM/LAV) were seeded with MT-4 cells, plaques were observed corresponding to the number of HTLV-III-positive cells plated. Plaque formation was inhibited by the addition of anti-HTLV-III-positive serum (neutralizing antibody) to the agarose medium. These data suggest that this plaque-forming assay technique should be useful for the quantitative analysis of AIDS-virus-bearing cells.