Selective impairment of TD IgG responses in Stat3^fl/flCD19^Cre/+ mice. TD antibody responses (left panels) and ASC formation (right panels) were assessed in Stat3^fl/flCD19^+/+ (Wt) and Stat3^fl/flCD19^Cre/+ (KO) mice immunized with TNP-CGG in CFA by TNP-specific ELISAs or ELISPOTs of splenocytes, respectively. (A) TD IgM antibody responses and ASC formation were equivalent between Wt and KO mice. TD IgG1 (B), IgG2a (C), and IgG2b (D) antibody responses and ASC formation were sharply diminished in KO mice. Filled symbols represent Wt mice; open symbols, KO mice. For TD antibody response data, each circle represents one mouse. TD ELISPOT data are representative of multiple experiments. Error bars represent SD. ^*P = .016 based on Mann-Whitney analysis.