Fig. 4.

Deficiency of IL-21R reduces class switch to IgG2a. On day 0, 8 million AM14 sd-Tg or AM14 sd-Tg.IL-21R KO B cells were purified (88–90% purity) and transferred into CD45.1 BALB/c recipients. Mice were either left untreated or injected with PL2-3. On day 6, splenocytes were assayed by flow cytometry to detect the 4–44⁺ population (A) and CD22^lo CD44^hi plasmablasts within the 4–44⁺ population (B). (C) Splenic 4–44⁺ AFCs of IgM or IgG2a; and (D) IgG2b, IgA, or IgG3 isotypes. Data are compiled from three independent experiments. *P < 0.05; ***P < 0.001; ****P < 0.0001, Mann-Whitney two-tailed test.