Figure 5
Conversion of CD4
+
CD25
–
T cells to CD4+
CD25+
Tregs in response to IFN-γ in vitro.
(A) CD4+CD25– T cells were purified from splenocytes of unprimed GKO (IFN-γ–/–) and WT (IFN-γ+/+) mice, respectively, and cultured in the presence and absence (medium control) of recombinant mouse IFN-γ for 24 hours. The resulting T cells (inhibitor) were examined for their ability to inhibit the proliferation of syngeneic CD4+CD25– T cells (responder) induced by antibodies to CD3/CD28. Results are given as percentage of inhibition rate. (B) Aliquots of the T cell preparations described above were analyzed in parallel experiments for the expression of Foxp3 by real-time PCR. (C) CD4+CD25– T cells described above were cultured with (gray contours) or without IFN-γ (open contours) in the presence or absence of anti-CD3 antibody. Intracellular expression of Foxp3 was measured in gated CD4+ T cells or CD4+CD25+ T cells. Indicated percentage refers to percentage of change between experimental groups with or without IFN-γ treatment. Purified CD4+CD25+ T cells (Tregs) from WT or GKO mice were stained for intracellular Foxp3 expression. Asterisks indicate that differences between groups are statistically significant; *P < 0.05.
