Radioresistance of carrier-specific helper thymus-derived lymphocytes in mice.

The effect of x-irradiation on the capacity of carrier-specific mouse T (thymus-derived) lymphocytes to exert a helper function for hapten-specific B (bone marrow-derived) lymphocytes in vivo has been investigated again. Helper function is abolished by exposure of such cells to x-irradiation before, or immediately after, transfer to adoptive hosts. On the other hand, when exposure to x-irradiation occurs under circumstances in which the carrier-primed cells are well-localized in the appropriate lymphoid organs, i.e., either in the carrier-primed animal or 24 hr after adoptive transfer to syngeneic recipients, the capacity of T lymphocytes to serve as specific helper cells is clearly radioresistant. Evidence indicates that x-irradiation results in undefined, and subtle, changes in the migratory capacity of mouse T lymphocytes, but not in abrogation of T-cell helper function.