RADIOSENSITIVITY OF T-LYMPHOCYTES AND B-LYMPHOCYTES .5. EFFECTS OF WHOLE-BODY IRRADIATION ON NUMBERS OF RECIRCULATING T-CELLS AND SENSITIZATION TO PRIMARY SKIN-GRAFTS IN MICE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 89  (2) , 367-378
Abstract
Whole-body exposure of mice to 50, 100, 300 or 500 rads resulted in an acute dose-related decrease in the number of viable recirculating T [thymus-derived] cells. The magnitude of this decrement became more pronounced with the passage of time. The dose-response relationship over this range of dosages appeared to consist of 3 components: a steep drop between 0-50 rad, a plateau between 50-500 rad and a 2nd drop between 300-500 rad. The residual radioresistant cells were able to recognize a histoincompatible skin graft during the initial 5 days after irradiation. Low to moderate doses (50-300 rad) abrogated the partial tolerance noted in nonirradiated receipients exposed to the skin graft for 5 days and then regrafted from the same donor source 25 days after complete removal of the primary graft. A large (500 rad) dose resulted in prolonged graft survival in comparison with the nonirradiated group. The subpopulation of recirculating T cells, which developed partial tolerance during a 5-day exposure to a homograft, was more radiosensitive than the effector subpopulation which was involved in graft rejection.