Figure 4.

Enhanced in vitro and in vivo responsiveness of crt^−/− naive T cells. (a) [³H]thymidine incorporation in purified naive CD4⁺ T cells stimulated with decreasing doses of plate-bound CD3ɛ mAb. •, crt^−/−; ▪, crt^+/+. cpm values (±SD) are from a single experiment representative of three. (b) DCs were loaded with the indicated concentrations of OVAp and used to stimulate purified naive CD4⁺ cells from DO11.10tg crt^+/+ (gray bars) and crt^−/− (black bars) chimeras. The displayed results are representative of four different experiments. Similar proportions of TCR transgenic cells were present in both crt^+/+ and crt^−/− naive T cell suspensions in all experiments (from 75 to 90%). (c) CD4⁺DO11.10tg H-2^d/b crt^+/+ (gray bars) and crt^−/− (black bars) cell recoveries from draining lymph nodes of adoptively transferred H-2^b/d mice immunized with OVAp-loaded DCs into the footpad at days 7 and 11 from immunization. The inset shows two representative draining lymph nodes at day 11 from immunization. Bar, 0.5 cm. (d) Intracellular staining for the indicated cytokine versus CFSE dilution of electronically gated CD4⁺DO11.10tg H-2^b/d cells from the draining lymph nodes of adoptively transferred H-2^b/d mice immunized with OVAp-loaded DCs at day 7 after immunization. This experiment was repeated three times with at least two animals/groups/time points with comparable results.