Increased autoantibody production in B/WcKO mice. (A-C) Sera of 6-month-old WT, B/WcKO, and WKO mice were tested by ELISA for IgG Abs specific for anti-ssDNA (A), anti-dsDNA (B), and chromatin (C). Data of individual mice are shown. Significance was calculated with the Mann-Whitney test. *P < .05 and **P < .01. (D) An autoantibody array chip was used to detect autoantibodies of IgM (left) or IgG (right) isotype against 73 different autoantigens (listed on the right). Sera from 6 WT mice (blue bar), 9 B/WcKO mice (green bar), and 7 WKO mice (gray bar) were tested. A serum from a lupus-prone MRL/NZM mouse (first row) served as a positive control. A red dot in the array indicates a 4-fold increase of autoantibody titer compared with average values in control sera.