Immunohistochemical analysis of cells infiltrating Rous sarcoma virus-induced tumors in chickens.

The aim of our experiments was the analysis of peripheral blood lymphocytes (PBL) and tumor infiltrating lymphocytes (TIL) in chicken inbred congenic lines, CB line with regressing and CC line with progressing RSV-induced sarcomas. For serological analysis, monoclonal antibodies to CD4, CD8, TCR1, TCR2, MHC class I and class II antigens were used. Significant differences determined by flow cytometry in CD4+ and CD8+ populations of PBL between CB chickens with tumors in progressive phase and CC chickens were not confirmed by means of TIL analysis. TIL were analysed either in suspension prepared from tumors by means of flow cytometry or on cryostat section of tumors. But using the histochemical method we observed more non-specific esterase positive cells in cryostat sections from CB than CC tumors. The role of macrophages in the regression of RSV-induced tumors in CB chickens has to be further analysed.