Fig. 2.

The age of the host environment determines the extent of an OX40-enhanced antigen-specific transgenic TCR T cell immune response. Two- or 12-month-old transgenic TCR CD4 T cells specific for a peptide of ovalbumin (323–339) were isolated from the spleens of DO11.10 mice and adoptively transferred into 2- or 12-month-old BALB/c recipients. Adoptively transferred mice were immunized s.c. with 500 μg whole ovalbumin and 50 μg anti-OX40 or rat IgG. A second dose of anti-OX40 or rat IgG was also given the next day. a Schematic of the adoptive transfer of transgenic TCR T cells. b Representative FACs plots of DO11.10 T cells (gated on CD4⁺ and the transgenic TCR⁺) expressing both IFNγ⁺ and IL-2⁺ from the antigen-draining LNs 4 days after challenge. c Enumeration of the DO11.10 T cells that co-expressed the cytokines IL-2 and IFNγ. Statistical representation: Student’s t test (two-tailed). For analysis, values of P ≤ 0.05 were considered significant and expressed as follows: *P ≤ 0.05 and **P ≤ 0.001