Transgenic Mouse Strains for B Cell Study

C57BL/6NCrSlc (B6) mice were purchased from Japan SLC. All the following mice were backcrossed to the B6 or B6-CD45.1 strain: B1-8^flox/+ mice (Lam et al., 1997 (link)), B1-8^hi mice (Shih et al., 2002 (link)), Igk^–/– mice (Chen et al., 1993 (link)), Cd19^cre/+ mice (Rickert et al., 1995 (link)), and Prkcd^–/– mice (Miyamoto et al., 2002 (link)). Prkcd ^fl/fl mice on the B6 background were developed by Drs. Niino, Shioda, and Sakimura (Niino et al., 2021 (link)) and purchased from the RIKEN BioResource Center (RBRC06462). Mice were immunized i.p. with 100 µg of NP₄₆-Ficoll (F-1420; Biosearch Technologies), 1 µg of PPS3 (169 X; American Type Culture Collection) or 100 µg of NP₄₀-CGG in alum (Haniuda et al., 2016 (link)) unless otherwise noted. For flow cytometry of spleen cells, mice were immunized i.v. with 100 µg of NP₄₆-Ficoll. Sex-matched 7–14-week-old mice were used for all experiments. All mice were maintained in the Tokyo University of Science (TUS) mouse facility under specific pathogen-free conditions. Mouse procedures were performed under protocols approved by the TUS Animal Care and Use Committee (Approval No. S19017 and S20011).