INTERSPECIFIC CHIMERISM—THE CHARACTERIZATION AND IMMUNOLOGICAL RESPONSIVENESS OF BOS TAURUSBOS INDICUS HAEMOPOIETIC CHIMERAS PRODUCED BY EMBRYO TRANSFER

Abstract

Summary. Bos inuriis-Bos imiicits twin calves were produced by embryo iran^fer and their degree of bacmopoielic chimerism and immune responsiveness examined. All 10 pairs of Friesiiin-Brahman twins were chimeric compared wilb only f> out of 12 pairs of Jersey-Brahm;in twins. In Ihe Friesian-Brahman twins. Friesian lymphoL-ytes predominated in all calves while in the Jersey-Brahman Iwins there was no uniform dominance of one cell type over anoiber. All calves th;it had chimeric lymphocyte popuUitions were also erythrocyte chimeras, although in two pairs of twins the genotype of the erythrocytes was different from the genotype of the lymphocytes. The lymphocytes of all chimeric calves failed to respond in mixed lymphocyte culture fMLCl lests to the lymphocytes of their co-twins but gave vigorous responses lo cells from other calves.Primary and secondary immune responses to keyhole limpet baemocyanin (KLH) antigen were studied in the efferent prefemoral lymph in normal Jersey. Friesian and Brahman calves, in 1 set of Jersey-Brahman twins anil in 5 sets of Friesian-Brabman twins. The immune responses of chimeric twins with genetically identical lymphocyte populations were quite dissimilar and were characteristic of the somatic genotype of the calf and not of the genotype of the lymphocyte population. The chimeric status of ihe cell population in the lymph did not change significantly during the response. These results suggest that either the genetic capacity of ii population of lymphocytes to recognize and respond to antigens can be modified during ontogeny in an ;ilien genetic environment or that a crucial determinant of the final outcome of an immune response is not the immunocompetent cell itself but tbe physiological and anatomical environment in wbicb il exists.

Bede Morris: a perspective from an early PhD candidate

“…Although he published extensively in many international journals, he contributed to the Australian Journal of Experimental Biology and Medical Science 1–27 (now Immunology & Cell Biology 28 ) over almost the whole of his scientific career, and clearly regarded this as a key forum for the promulgation of his work on the role lymphatics in the whole animal.…”

Embryo Manipulation in Research and Animal Production

“…This natural model has been extremely productive in studies of immunological tolerance (Owen 1945;Burnet and Fenner 1949) and differentiation of organs of the reproductive tract (Jost et al 1972). Summers et al (1983bSummers et al ( , 1984 used embryo transfer to produce an artificial situation in which bovine fetuses of the two species, Bos taurus and Bos indicus, shared the one uterus and thus had the opportunity of becoming chimeric and immunologically tolerant to one another. These experiments produced a number, of interesting results.…”

“…At present the composition of chimeric animals cannot be predetermined although in some genetic combinations a preponderance of one genotype can be expected in certain cells (Tuffrey et at. 1973;Summers et at. 1984).…”

Degree of leukochimerism with calf age in Angus‐crossbred twin sets

“…In a previous study in which researchers created twins by embryo transfers with Jersey, Brahman, Friesian and Angus breeds, evidence was provided suggesting that chimerism changed with age (Summers et al, 1984), although the effect of age was not statistically tested. We hypothesized that circulating WBC populations shortly after birth would reflect the combined genetic make-up of both twins, whereas with increasing age the population would reflect the hematopoeitic stem cell population which had established within the individual.…”