Figure 5: Anti-DR6-specific antibody delays lupus-like syndrome progress in lupus-prone mice.

(a) Effect of 25-1 Ab (25-1) or nonspecific rat IgG (ctrl-IgG; 10 μg ml⁻¹) administration on Il-21 production of CD3⁺ CD4⁺ PD1^high/int CXCR5^high/int CXCR4⁺ cells was assessed as described in Fig. 4f. (b–d) 15-week-old female BWF1 mice were intraperitoneally administered nonspecific control rat IgG (ctrl-IgG) or 25-1 Ab (300 μg per mouse every 2 days, from 15 to 27 weeks old; n=8 per group). (b) anti-dsDNA Ab production in sera of these mice was assessed by ELISA. Error bar: s.d. (n=8 per group). (c) Percentages of proteinuria positive (>100 mg protein per dl) mice in each group are shown (P=0.0314 by Gray test). (d) The survival rate of these groups is also shown (P=0.0251 by Log-rank test). (e–i) Twenty-four-week-old proteinuria-positive female BWF1 mice were treated as described above (until 32 weeks old) (n=4 per group). Two days after the last administration, frequency of DR6⁺ cells in CD4⁺ T cells (e), GL7⁺ GC B cell in B220⁺ B cells (f) or syndecan-1^high B220⁻ plasma cells in live total splenocytes (g) obtained from these mice was assessed by flow cytometry. Gate strategies that were used for identifying each cell population were shown in Supplementary Fig. 15a–e. Error bar: s.d. (n=4 per group). (h) Splenic cryosections obtained from these mice were stained by GL7 Ab for detecting GCs (magenta). The sections were also stained by anti-B220 Ab (green) for detecting B cell area. Bar, 100 μm. The results obtained from the other sections are also represented in Supplementary Fig. 9. (i) Area of GL7⁺ in each section was also calculated. Error bar, s.d. (n=4–6 per section). Asterisks in each panel indicate statistical significance (P<0.05, Student’s t-test).