Fig. 3.

B7-DC⁺ B cells do not suppress, but moderately augment, antigen-specific T-cell proliferation in vitro. (A) In vitro suppression assay. Single-cell suspensions of the whole spleen from OT-II or OT-I mice were cultured with or without B7-DC⁺ or B7-DC⁻ B 0cells or CD4⁺CD25⁺ Tregs from naïve aged mice in the presence of cognate OVA-specific peptide (OVAp). (B) In vitro proliferation assay. OT-II or OT-I T cells (CD4⁺ or CD8⁺ OVA specific, respectively) were sorted by flow cytometry after magnetic purification, carboxyfluorescein diacetate succinimidyl ester (CFSE) labeled, and cultured with or without sorted B7-DC⁺ or B7-DC⁻ B cells from aged mice in the presence or absence of the respective OVAp. T-cell proliferation was measured by CFSE dilution. The data are representative of five independent experiments with similar results. OVA, ovalbumin.