B-cell depletion with CD22/cal inhibits the development of histologic CIA. Mice (n = 10/group) were immunized on day 0 with collagen II in CFA and injected on days 5 and 10 with PBS or CD22/cal. Paws were collected on days 25 or 75 for histologic evaluation. (A) Histopathology of hematoxylin and eosin-stained joints of front paws of control PBS mice collected on day 25. The paws were infiltrated by neutrophils and macrophages consistent with active inflammation. (B) Histopathology of joints of front paws of CD22/cal-treated mice (collected on day 25) showing normal joint architecture. Joint histopathology of (C) control and (D) of B-cell-depleted mice on day 75 after immunization with collagen II. Paws from control mice had remodeling and destruction of the joints consistent with chronic arthritis; paws from B-cell-eted mice had normal joints.