The cellular control of delayed hypersensitivity to Staphylococcus aureus in mice

The cells which suppressed delayed hypersensitivity (DH) to Staphylococcus aureus in the mice were non-phagocytic, adhered to nylon wool and possessed surface immunoglobulin but no detectable Thy 1. antigen. They were probably B lymphocytes and the suppression which they mediated appeared to be specific. The mature suppressor cells were radiosensitive. Their precursors were sensitive to large doses of cyclophosphamide. Suppressor-cell activity in the spleen reached a peak after two subcutaneous S. aureus infections and declined thereafter. This decline might be related to the appearance of DH to S. aureus in mice after four or more staphylococcal infections.