PRF1 and infection: Although the proportion of CD8+ CTLs decreased from 5.48% to 4.13% after infection (Figure 5B), these cells exhibited enhanced expression of cytolytic genes (nkl, gzmb, gzma, and prf1) and chemokines (ccl5l, ccl20, mcp1b, and ccl4l), while decreased the expression of il34 (Figure 5E).