title: Cytolytic activity of circulating human monocytes on transformed and untransformed human fibroblasts.
abstract: Monocytes from the peripheral blood of 10 normal adult human donors were tested for their cytolytic activity on untransformed or SV40-transformed, early passage, human fibroblasts. Two pairs of human fibroblast lines (2303 and SV40-2303, 2931 and SV40-2931) were used and lysis was assessed in terms of release of [3H]thymidine from prelabelled target cells over a 72-h incubation period. High levels of cytolytic activity were consistently observed on transformed fibroblasts at attacker to target cell (A:T) ratios ranging from 5:1 to 40:1. Low, but significant, lysis of untransformed cells was observed only with two donors at the highest (40:1) A:T ratio tested. With all donors, the cytolytic activity on transformed lines was significantly greater than on untransformed fibroblasts. Thus natural human monocyte-mediated cytotoxicity is preferentially expressed on transformed, as compared to untransformed, cells although sparing of the latter is not absolute.
mesh_terms: D000328:Adult; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D003602:Cytotoxicity, Immunologic; D005347:Fibroblasts / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D015470:Leukemia, Myeloid, Acute / Q000276:immunology; D009000:Monocytes / Q000276:immunology*