T cells may express multiple activities: specific allohelp, cytolysis, and delayed-type hypersensitivity are expressed by a cloned T-cell line.

A T-cell line that recognizes private specificities encoded in the H-2 IA subregion in the proliferative response, cytotoxic activity, delayed-type hypersensitivity, and allohelp reaction with B cells has been cloned. The individual clones were assayed for ability to express the activities of the parent line. Results show that the cloned sublines tested are able to perform all the activities of the parent line. It is suggested that T cells may express multiple activities and that the apparent monofunctionality of T cells is due to regulation of these activities.