CD8A and infection: Since we could not also observe significant differences in T cell responses by using an in vitro culture system in which two immunization groups were directly infected with O. tsutsugamushi genotypes (Figure 6(C)), we further screened CD8+ T cell epitopes using a 10-mer peptide library derived from CBs of TSA56 and examined whether the immunogenic epitopes themselves could provide protective immunity against lethal infection (Figure 7).