FIG. 3.

Antibody responses and IgG isotype profile in CD8-depleted CD4⁺ T-cell-deficient C57BL/6 mice after immunization with inactivated PR8 virus. CD4⁺ T-cell-deficient mice (n = 5) were depleted of CD8 T cells by i.p. injection of MAb. 2.43. These mice were then i.m. immunized with formalin-inactivated PR8 virus (10 μg/mouse) at day 0 and boosted at day 15 with the same dose. Pre, serum samples before immunization. Prime, serum samples taken at day 15 after first immunization. Boost, serum samples taken at day 10 after boost.