Figure 5.

T-cell receptor (TCR)-activated effector CD4⁺ T cells do not induce the formation of osteoclasts. The cells were activated with anti-CD3 monoclonal antibody in the presence or absence of collagen IV (Coll IV). The cells were washed and co-cultured with monocytes in the presence of macrophage colony-stimulating factor (M-CSF). After 8 days, the cultures were washed and stained for tartrate-resistant acid phosphatase (TRAP) activity as described in the Materials and methods. The results are presented as in Fig. 4(b).