These results indicate that the elimination of a majority of T. gondii cysts by anti-cyst activity of CD8+ immune T cells resulted in a selection of the cysts that express significantly increased mRNA levels for at least the five selected secretory molecules, GRA1, GRA2, GRA3, GRA7, and ROP35, suggesting that these GRA and ROP proteins could mediate in the capability of T. gondii cysts to persist in the presence of anti-cyst CD8+ T-cell immunity. This evidence concerns the gene CD8A and cyst.