Immune Responses In Irradiated Mice I. Radiosensitivity of Antibody Response Against Sheep Erythrocytes In C57BL/6 Mice

The effect of whole body irradiation on antibody response to sheep erythrocytes was investigated in C57BL/6 mice. 1) The degree of reduction in antibody production observed shortly after irradiation increased with the increase in X-ray dose. Recovery from the damage of immunocompetent cells was not complete even one month after irradiation. 2) Some mice exposed to 300 R or more could not produce antibodies immediately after irradiation. Inability to produce antibodies in these mice may largely be attributable to the damage of B cells, since anti-2, 4, 6-trinitrophenyl (TNP) antibody was produced in all thymectomized mice, when they were irradiated with 300 R or more and immunized two months after irradiation. 3) Antibody production ceased in thymectomized mice sooner than non-thymectomized mice irrespective of radiation dose. 4) Neither nonthymectomized nor thymectomized mice could produce IgG antibodies after irradiation of 40O R or more. These irradiated mice, however, produced IgG antibody, when 1×106 activated T cells were transferred together with sheep erythrocytes. These results indicate the inability to produce IgG antibody may be attributable to lack of T cells participating as helper cells in IgG antibody production.