Suppression of autoantibody formation. (A
B) At day 56 post first type II collagen (CII) immunization, serum samples were collected from C57BL/6 mice (n = 22) and RORγt Tg mice (n = 21) for measurement of CII-specific total IgG levels (A), and CII-specific IgG1, IgG2a, IgG2b, and IgG3 (B) by ELISA. Horizontal lines represent the mean values. (C
D) At day 10 post first CII immunization, the expression of CXCR5 (C) and the expression of inducible T-cell co-stimulator (ICOS) and programmed cell death-1 (PD-1) (D) in draining lymph nodes (LNs) were analyzed by fluorescence-activated cell sorting (FACS). Data represent gated CD4+
(C) and CXCR5+CD4+ cells (D). Bar graphs show percentages of CXCR5+ cells (C) and ICOS+PD-1+ cells (D). (E) cDNA was obtained from sorted CXCR5+CD4+ T cells isolated from draining LNs on day 10 post first CII immunization, and expression levels of Bcl-6 and IL-21 were analyzed by real-time PCR. Data are representative of two independent experiments with similar results, and represent the mean ± standard error of the mean. *P < 0.05, versus C57BL/6 mice, Student’s t-test.