ELISA titration of mouse serum anti-flagellin against recombinant flagellins CBir1 and Fla-X with secondary antibodies specific for mouse IgG, IgG1, and IgG2a antibodies. Colitic C3H/HeJBir serum (pool of five) versus noncolitic C3H/HeJ serum (pool of two) was used in the upper panel and colitic mdr1a^–/– serum (pool of five) versus noncolitic FVB serum (pool of five) was used in the lower panel.