抄録
Guinea pig embryos 2 or 3 days before birth were thymectomized or sham-operated as soon as possible after the delivery of them by the cesarean operation. Several days after operation they were injected into foot pad with heat-killed BCG in saline. As a result both thymectomized and shamoperated animals similarly became tuberculin sensitive one or two weeks after the sensitization. Moreover, the circulating antibody formation as well as the gain of body weight were not affected by the thymectomy. On the other hand, peripheral blood leukocytes diminished slightly in the thymectomized group. Histological examinations of lymphoid organs at various stages of gestation revealed that the thymus and axillar lymph nodes were already lymphoidal in early fetal life. On the contrary, the spleen remained reticular in nature until a few days before birth. These findings indicate that the delayed type hypersensitivity is not affected by the thymectomy in the guinea pig embryos as well as the humoral antibody formation.
