FETAL RESPONSE TO IMMUNIZATION.
Annual progress rept. no. 4, 1 Apr 67-30 Jun 68,
JOHNS HOPKINS UNIV BALTIMORE MD SCHOOL OF MEDICINE
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A broad study of the fetal immunologic response to immunization was undertaken. The fetus is able to respond actively to antigenic stimulus quite early in gestation, but develops this competence to different antigenic stimuli at different stages of development. The fetus is capable of immunologic response in the absence of any organized lymphoid structures in either regional nodes or spleen, and apparently even prior to the development of a lymphoid thymus. Thymectomy of the fetus at the end of the first third of gestation, while retarding its lymphoid development, fails to affect significantly its immunologic development. The suggestion that the Peyers patches of the intestinal tract might be the mammalian analog of the avian Bursa of Fabricius as a central lymphoid control organ was tested by extirpation of the fetal intestinal tract, a procedure without effect on the normal course of immunologic development. It was found that antilymphocyte serum prepared in the rabbit would, when injected into the fetal lamb, produce a severe lymphoid depletion, accompanied by an inability to form circulating antibody, to reject orthotopic skin allografts, and even an inability to reject grafts of guinea pig skin. A study of the secretory immunoglobulins of the sheep colostrum, saliva, tears, etc. discloses that the principal component in this species is a gamma G-1 immunoglobulin derived from the blood, rather than the locally formed gamma A immunoglobulin with an attached special polypeptide chain typical of many other species. Author
- Medicine and Medical Research