2A). The total number of OT-II T cells in spleen was increased in 11c.OVA (Fig. 2B), indicating the expansion of the OT-II population was consistent with the

division indicated by CFSE dilution. As previously reported for naïve T cells 13, 17, 18, we have found that memory CD8+ T cells exert a transient period of effector function upon interaction with steady-state DC 4. To test whether this was observed here, cytokines in Raf inhibitor culture supernatant of splenocytes restimulated in vitro with or without OVA323–339 were measured by ELISA. This showed that, despite the increase in the number of OT-II T cells in spleens of 11c.OVA recipients 3 days after transfer (Fig. 2B), IFN-γ production was reduced relative to nontransgenic recipients (Fig. 2C). Similarly, IL-2 production Lumacaftor was reduced in 11c.OVA OT-II recipients and a small amount of IL-4 production

in response to OVA323–339 detected in 11c.OVA recipients. To further analyze this, we performed intracellular cytokine staining and analyzed cytokine production specifically in transferred OT-II T cells. This showed that fewer OT-II T cells recovered from 11c.OVA recipients produced IFN-γ and IL-2 relative to those from nontransgenic recipients (Fig. 2D) and also relative to IFN-γ production observed before transfer (Fig. 1B). IL-4 and IL-10 were not detected in either nontransgenic or 11c.OVA recipients. Additionally, Foxp3 was not detectable in OT-II recovered from spleens of 11c.OVA or nontransgenic recipients (data not shown). Overall, these

data demonstrate that the activation of OT-II memory-phenotype CD4+ T cells by steady-state antigen-expressing DC induces proliferation with subsequent damping of IFN-γ and IL-2 production. We next analyzed the time-course of OT-II accumulation in lymphoid and nonlymphoid tissues. In nontransgenic recipients 1 day after transfer, OT-II memory T cells were recovered in largest numbers from the spleen, but by 3 days post-transfer, OT-II T cells appeared to have redistributed from spleen and started to accumulate in larger numbers in LN and lung (Fig. 3) and Vitamin B12 from this point OT-II cells were established as relatively stable populations in spleen and LN (no significant differences were observed between d3, d7, d21, d28 in spl and LN, respectively) and persisted in these sites in similar numbers for up to 4 wk post-transfer. In 11c.OVA recipients, consistent with proliferation demonstrated by CFSE dilution, the total number of OT-II cells recovered from spleen initially increased between 1 and 3 days post-transfer (p<0.01) and then diminished (p<0.001, d3 versus d7; d7 versus d21; d21 versus d28), indicating a period of population contraction following the initial transient expansion. In LN, the pattern of OT-II accumulation in 11c.