Fig. 4.

Requirement of CD4⁺ cells but not CD8⁺ cells and B220⁺ in the development of delayed-type hypersensitivity (DTH) arthritis. B220⁺ (a), CD8⁺ (b) or CD4⁺ (c) cells were depleted from splenocytes of BALB/c mice using immunomagnetic beads conjugated with monoclonal antibodies (MoAb) to B220, CD8 and CD4, as described in Materials and methods. Then these depleted splenocytes (▴) or undepleted splenocytes (○) were transferred adoptively (1 × 10⁷ cells/0·5 ml/body) into SCID mice. The next day, the SCID mice were immunized with methylated bovine serum albumin (mBSA) (0·5 mg/body). Four days after the immunization, the mice were injected intravenously with anti-CII MoAb (1 mg/0·5 ml/body). Seven days after the immunization, DTH arthritis was elicited in the mice by challenging mBSA into the footpad (0·05 mg/0·05 ml/footpad). The clinical scores were graded, as described in Materials and methods. The data were expressed as the mean ± s.e.m. of the five mice in each group. The clinical scores of the SCID mice reconstituted with the CD4⁺ cell-depleted splenocytes were significantly different from those of the SCID mice reconstituted with the undepleted splenocytes (*P < 0·05; **P < 0·01).