Antigen-specific IgE production is diminished in Stat5a^−/− mice but not in Stat5b^−/−mice.

(A) The titer of anti-OVA IgE antibody in sera was assessed at 2 weeks after the second immunization by a 24-hour passive cutaneous anaphylaxis (PCA) reaction. Data are means ± SD for 10 mice in each group. *P < .005. (B-C) Anti-OVA IgG1 (B) and IgG2a (C) antibodies in sera were assessed at 2 weeks after the second immunization by ELISA as described in “Materials and Methods.” Data are means ± SD for 10 mice in each group. *P < .01, **P < .005.