Figure 3: Protection against plasmodium infection in IrPySpz-immunized MHC-I- -Tg mice after depletion of CD8+ T cells or CD4+ T cells. (a) Groups of MHC-I- -Tg mice (4 per group) were immunized with 1 × 105 IrPySpz via IM injection following challenge with 5 × 104 viable P. yoelii sporozoites via IV injection at 2 weeks after immunization. Some cohorts of mice were treated with rat anti-CD4 mAb (GK1.5) or anti-CD8 mAb (YTS 169) 3 days and 1 day prior to challenge with P. yoelii sporozoites. Naive MHC-I- -Tg mice were challenged as infection control. The value of parasite burden was described previously. (b) The dot plots by flow cytometric analysis represent the frequency of total CD4+ and CD8+ T cells among the CD3+ T-cell population of splenocytes, following the indicated antibody treatment to IrPySpz-immunized MHC-I- -Tg mice.