Conversion of human fibroblasts to tissue macrophages by the Snyder-Theilen feline sarcoma virus (ST:FeSV) is associated with the de-novo expression of IL-1 alpha, IL-1 beta, IFN-alpha, TNF-alpha, GM-CSF, and CD4.

In an earlier study, we have demonstrated the conversion of human fibroblasts (HF) to tissue macrophages (TM) by the Snyder-Theilen feline sarcoma virus (ST:(FeSV)) [1]. The present study shows that conversion of cultured HF by the ST:FeSV to TM resulted in the de-novo expression of interleukin-1 alpha, IL-1 beta, interferon-alpha, tumor necrosis factor-alpha, granulocyte-macrophage colony stimulating factor, and CD4. The conversion of HF to TM was also associated with increased expression of non-specific esterases as well as increased amount of ingested lipid material by the TM. Clonotypic and organotypic analyses of cells infected with the ST:FeSV(FeLV) showed a similar degree of conversion to TM among eleven individual clones of skin fibroblasts, and among fibroblasts obtained from eight different organs. These findings bear on the origin (heterogeneity) of TM, the nature of TM-induced cytokines, and the potential role of ST:FeSV-recruited TM during immune reactions in vivo.