Figure 1.

Lpr/sIgM^−/− mice developed elevated levels of IgG to dsDNA and histones. Serially diluted sera from 3- and 6-month-old lpr and lpr/sIgM^−/− female littermates were assayed by ELISA for the levels of each IgG isotype (A and B) and the levels of IgG specific to dsDNA (C and D) or to histones (E and F). ●, lpr/sIgM^−/− mice; ○, lpr mice. Horizontal bars indicate the median levels of IgG antibodies. * and **, P values of <0.005 and <0.05, respectively, between lpr and lpr/sIgM^−/− mice. Values below “//” are considered below the detection of the assay.