Influence of adoptive transfer of regulatory DCs on the frequency and phenotype of memory CD4 T cells in vivo. (A) Schematic of experimental design of the induction of antigen-specific CD4 T-cell response in vivo with or without adoptive transfer of diffDCs. (B) Frequency of peripheral blood CD45.1⁺ CD4⁺ OT-2 T cells after adoptive transfer into C57BL/6J mice immunized with OVA, presented as the percentage of total CD4⁺ T cells. (C) The percentage of peripheral blood and splenic CD45.1⁺ CD4⁺ OT-2 memory T cells among total CD4⁺ T cells was assessed by flow cytometry in the mice 30 days after immunization. Absolute numbers of CD45.1⁺ CD4⁺ OT-2 memory T cells present in spleen were counted. NS indicates no statistical significance. (D) The expression of CD62L and CD44 on CD45.1⁺ CD4⁺ OT-2 memory T cells and endogenous CD4⁺ T cells from the spleen of immunized mice 30 days after immunization. Numbers in the plots indicate the percentage of gated cells. Similar results were obtained in at least 3 independent experiments.