Specific unresponsiveness in nude mice given antigen before T cells

Nude mice given antigen before being given congenic T cells are specifically tolerant to that antigen and recovery of the ability to respond takes at least 2 weeks. If, after giving antigen, spleen cells are transferred to irradiated congenic recipients together with normal congenic thymocytes, the recipients usually remain unresponsive. Treatment of the spleen cells with supernatant from lysed cells renders them responsive in transfer. Spleen cells from unresponsive mice do not suppress normal spleen cells in transfer and the unresponsiveness is not broken by allogeneic cells. It is therefore probable that this is a case of reversible blocking of the B cell receptors and that T cells are not involved.