Immune Lysis of Thymus and Spleen Cells of Embryonic and Neonatal Mice

Abstract

Summary The cytotoxic effect of H-2 isoantibodies and complement on thymus and spleen cells of embryonic and neonatal C3H mice was investigated. The sensitivity of the cytotoxic test employed was increased by using small numbers of cells and by washing the antibody-sensitized cells prior to the addition of complement. Spleen cells showed a low though definite sensitivity to the cytotoxic effect of isoantibodies and complement as early as on the 15½ day of gestation and throughout the rest of gestation. During the first days of life the sensitivity of the spleen cells increased rapidly, and thereafter it gradually increased further to adult levels. The thymus of 15½-day-old embryos was almost completely refractory to the cytotoxic effect of isoantibodies and complement. In the 17½-day-old embryo the thymus cells had already developed a high sensitivity. The sensitivity of the thymus cells showed only minor fluctuations throughout the gestation period and remained unchanged during the 1st month of life. A higher sensitivity was found in thymus cells of 6-month-old mice. Fresh guinea pig serum had a distinctive toxicity for mouse thymus cells, probably due to the action of heat-labile naturally occuring antibodies in the presence of complement. Sensitivity of the thymus cells to the toxic effect of guinea pig serum appeared between the 15½ and 17½ day of gestation.