Extended Data Figure 7: IgG1 inhibits IgG3-induced cryoglobulin kidney disease independent of complement and FcγRIIB and better than IgG2a and IgG2b.

a, Wild-type (WT) mice (4 per group) were injected i.v. with 4 mg of mouse IgG1, IgG2a, IgG2b or IgG3 anti-TNP monoclonal antibody and s.c. with 100 µl of TNP-goat serum on days 0 and 1. Urine leukocyte esterase and blood was measured before injections and on day 1 and day 2. b, Urine leukocyte esterase (LE) and blood for BALB/c wild-type and C3⁻ mice (4 per group) injected i.v. with 4 mg of IgG3 anti-TNP monoclonal antibody and s.c. with 400 µl of TNP-goat serum on day 0 and day 1. c, Wild-type and FcγRIIB-deficient (FcγRIIB⁻) mice (4 per group) were injected s.c with 100 µl of TNP-goat serum and i.v. with 4 mg of IgG3 anti-TNP plus or minus 5 mg of IgG1 anti-TNP on day 0 and day 1. Urinalysis on days 0, 1 and 2. d, BALB/c mice were injected i.v. with 4 mg of IgG3 anti-TNP and s.c. with 1.4 mg of TNP-BSA on days 0 and 1. Some mice were also injected with 0.625, 1.25, 2.5 or 5 mg of switch variants of IgG1, IgG2a or IgG2b anti-TNP monoclonal antibodies on days 0 and 1. Urine protein was determined on day 0 (data not shown), day 1 (top) and day 2 (bottom). Results are pooled from a total of seven experiments. Group size was as follows. IgG3 alone: 19 mice; 0.625 mg of IgG1, IgG2a or IgG2b: 4 mice; 1.25 mg of IgG1, IgG2a or IgG2b: 8 mice; 2.5 mg of IgG1, IgG2a or IgG2b: 6 mice; 5 mg of IgG1, IgG2a or IgG2b: 8 or 9 mice. The significance of differences between treatment groups was determined as described in the legend to Fig. 4f. *P < 0.05 as compared to IgG3 alone; †P < 0.05 as compared to IgG2b plus IgG3; e, Binding of the Ig isotype switch variants to ELISA wells coated with TNP-BSA, reported as percentage of maximal binding. f, Binding of the Ig isotype switch variants to ELISA wells coated with IgG3 anti-TNP monoclonal antibody. g, Binding of IgG3 and the Ig isotype switch variants to ELISA wells coated with themselves.