Differential target cell susceptibility to SFV-immune cytotoxic T-cells

Semliki Forest virus (SFV) infects a variety of murine cell types of H-2k haplotype. However, only L929 fibroblasts can be productively infected. Thioglycollate-induced peritoneal macrophages (TGM), and BW 5147 thymoma cells can be infected with SFV as demonstrated by SFV antigen expression on the cell surface and intracellularly. SFV-immune cytotoxic T (Tc) cells lyse only infected TGM and L929 target cells, however different times after infection are required for lysis of these two cell types. Split clone limiting dilution and cold target competition experiments are consistent with the interpretation that these two cell types display qualitatively different epitopes to SFV-immune Tc cells but do not exclude additional quantitative differences.