Relationships among differentiated T-cell subpopulations. III. Radioresistance of delayed hypersensitivity to heterologous erythrocytes

Effects of whole body irradiation with 600 rad on delayed hypersensitivity, direct cytotoxicity and antibody production were examined in mice immunized with chicken erythrocytes (CRBC) or sheep erythrocytes (SRBC) in saline. Delayed footpad reactions to CRBC were not affected by the exposure to irradiation 3 h before or after antigenic stimulation. On the other hand, direct cytotoxic activities in spleen cells and antibody titres to CRBC were reduced by such exposures. Additionally, delayed footpad reactions to SRBC were not affected by the exposure to irradiation. Generation of effector cells responsible for delayed footpad reactions proved to be resistant to irradiation.