Histiocytic conversion of human adult skin fibroblasts by the Snyder-Theilen feline sarcoma virus

Oncogenes are apparently involved in the transformation/neodifferentiation of human cells. We now report a novel example of transformation/neodifferentiation: the specific conversion of cultured human adult skin fibroblasts (HSF) to histiocytes (tissue macrophages (TM)) by the Snyder-Theilen feline sarcoma virus (ST: (FeSV)). The de novo conversion of cultured HSF was demonstrated in a large fraction of ST:FeSV (FeLV)-transformed foci in the presence of dexamethasone (DX). Identification of tissue macrophages in ST:FeSV(FeLV)-infected HSF cultures was established by light-and transmission electron microscopy, histochemistry, immunohistochemistry, adherence-reattachment, latex particle uptake, and secretion of bioactive interleukin-1. The ST:FeSV gene and glucocorticosteroids, or other naturally occurring hormones, may play a role in morphogenetic processes within cells from a variety of normal and diseased tissues in situ, including induction of non-bone marrow, mesenchyme-derived, tissue macrophages.