CD44 and infection: Vaccinated/PPK-treated and Mock-vaccinated/untreated rabbits were euthanized on day 58 post-infection, and the frequencies of HSV-1 peptide-specific CD8+ T cells of the resident memory CD8+ T cells expressing CD103, CD69; effector memory CD8+ T cells expressing CD62L, and CD44 among total cells (i.e., effector memory [TEM], resident memory [TRM], and central memory [TCM]) were determined by FACS, as described in Materials and Methods.