Figure 5.

TCRβ+CD138+ cells activate autoreactive B cells when auto-antigens are included in the culture. (A–D) Sorted splenic TCRβ+CD138+ and TCRβ+CD138- cells from 12 weeks old MRL/Lpr mice were co-cultured with purified splenic B cells from the same mice for 5 days. (A) DNA was included in the co-cultured cells and culture supernatant anti-dsDNA IgM and IgG antibodies were measured by ELISA. Mean ± SD of six mice from three independent experiments are plotted. (B) T and B cells were incubated as mixed (contact) or separated with Transwell^® (separate) in the presence of DNA. After gating-out TCRβ+ T cells, the differentiation of B cells into plasma cells (CD19^intCD138+) was quantified by flow cytometry. Mean percentages ± SD of six mice from three independent experiments are plotted. (C) SM was included in the co-cultured cells and differentiation of B cells into plasma cells (CD19^intCD138+) were quantified by flow cytometry after gating-out TCRβ+ T cells. Mean percentages ± SD of six mice from three experiments are plotted. (D) Cells were incubated in the presence of antibody against CD4 or control IgG and the differentiation of B cells into plasma cells was quantified by flow cytometry. Mean percentages ± SD of three independent experiments are plotted. (E) Splenic TCRβ+CD138+ and TCRβ+CD138- cells from 10 to 12 weeks old MRL/Lpr mice were sorted and then adoptively transferred into 5 to 6 weeks old MRL/Lpr mice with or without DNA. Mice that received PBS or DNA only served as control. Serum anti-dsDNA IgG and IgM antibody as well as proteinuria levels at indicated days were measured. Mean ± SEM of five mice are plotted. Two tailed Mann-Whitney rank sum test was used to calculate statistical significance.