Fig 1: Effect of Bruton’s tyrosine kinase (BTK) inhibition on the affinity for topo I of topo I-reactive B cells and the development of fibrosis in the topo I-induced systemic sclerosis (SSc) model mice.(A) Frequencies of topo I-reactive B cells in splenic B cells from mice immunized four times with topo I and from mice treated with a BTK inhibitor along with topo I were examined. Ibrutinib (12.5 mg/kg/day, administrated orally) was used as the BTK inhibitor. (B) We measured the dermal thickness, lung fibrosis score, titer of serum IgG anti-topo I antibodies, and titer of IgG anti-topo I antibodies produced by individual topo I-reactive B cells in these mice (n = 6). Frequencies of cytokine-producing topo I-reactive B cells (C, total 200 cells) and the amount of produced cytokine (D, 100 cells each) are shown in the pie charts. (E) Topo I-reactive B cells (104 cells) obtained from these mice (n = 6) were adoptively transferred to wild-type mice, and the dermal thickness and lung fibrosis score were measured after 14 days. Topo I, topo I-induced SSc model mice; Topo I + BTKi; BTK inhibitor-treated topo I-induced SSc model mice. The bar graphs show the mean + SD. *p<0.05, ***p<0.005. Figure 7—source data 1.Source file for the effect of Bruton’s tyrosine kinase (BTK) inhibition on the affinity for topo I of topo I-reactive B cells and the development of fibrosis in the topo I-induced systemic sclerosis (SSc) model mice.This archive contains all data used for the quantitative analysis shown in Figure 7.