Q489A and G490A prime endogenous site V-specific T cell responses in the presence of the dominant TAg determinants. (A–C) B6 mice were immunized with the indicated B6-derived cell lines. 10 days following immunization, spleens were harvested and cells were stained with anti-CD8 and site V MHC-tetramer. The percentage of endogenous site V-specific CD8+ T cells was assessed ex-vivo or following two rounds of in-vitro restimulation with K-3,1,4 cells. (A) Values indicate the percent of CD8+ T cells that are site V MHC-tetramer positive. For comparison purposes, the data for site I (B) and site IV (C) are plotted along with the CD8+Tet-V+ T cell response to site V. Each data-point represents an individual mouse, and the open and closed paired symbols represent data from the same animal. Results are representative of at least two independent experiments with three mice per group.