Immune responses in irradiated mice. I. Radiosensitivity of antibody response against sheep erythrocytes in C57BL/6 mice.

*愼 殿玲子 ,**野 本亀久雄,**武 谷健二:九 州大学医学部放射線科学 教室,微 生物学 教室 福岡市東区馬 出3-1-1〒812 Radiosensitivity of T and B lymphocytes/In vivo X-irradiation/Immune Response to SRBC 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) anti body 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 non thymectomized 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.