Specificity of allogeneic and xenogeneic cell recognition in the fetal lamb
Asantila, T.; Toivanen, P.
Journal of Immunology 117(2): 555-562
1976
ISSN/ISBN: 0022-1767 PMID: 133189 Document Number: 109197
Cells prepared from liver, thymus, and spleen of fetal lambs at different stages of gestation were confronted with allogeneic and xenogeneic cells and UV light together with a subsequent restimulation was used to study the specificity of the reaction. The response of fetal liver cells was not based on the existence of specifically recognizing cellular subpopulations; the response was concluded to be due to stimulatory products released by the stimulating cells or to the multipotentiality of the responding cells. Specifically recognizing cells first appeared in the thymus at 58 days postconception and in the spleen at 70 days. In the response of sheep lymphocytes against allogeneic and xenogeneic cells, a cross-reactivity occurred. Fetal lamb lymphocytes were also capable of recognizing intraspecies differences on the xenogeneic cells. This capacity developed simultaneously with specific recognition of allogeneic cells. No clear difference was observed in the reactivity of fetal thymus cells and spleen cells when compared to that of adult peripheral blood lymphocytes. Immunologically specific recognition of foreign cells is probably created in the sheep during the early intrauterine development.