Figure 3.

Costimulatory requirements for activation of adoptively transferred CD8 T cells. C57BL/6-Ly5.2 OT-I T cells (1 × 10⁷) were injected i.v. into C57BL/6-Ly5.1 mice. Two days later 5 mg of ovalbumin was administered i.p. One hundred micrograms of the indicated antibody was injected i.p. daily beginning on the day of immunization. Three days after immunization cells were isolated and analyzed for Ly5.2 and CD44 expression by fluorescence flow cytometry. Numbers in parentheses indicate the mean fluorescence intensity of CD44 expression for the donor cells. Numbers above the plots indicate the total number of donor cells. This experiment has been performed three times with similar results.