|Zajchowski, L. - UNIV OF CALGARY-CANADA|
|Clark, M. - UNIV OF GUELPH-CANADA|
|Etches, R - ORIGIN THERAPEUTICS CALIF|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 8, 2002
Publication Date: October 1, 2002
Citation: Bacon, L.D., Zajchowski, L., Clark, M.E., Etches, R.J. 2002. Identification and evaluation of major histocompatibility complex antigens in chicken chimeras and their relationship to germline transmission. Poultry Science. 81:1427-1438. Interpretive Summary: When donor cells from a black-feathered line of chickens were transferred into a recipient embryo from a white feather line the resulting chick would frequently possess black feathers attributable to the donor cells, i.e. the chick was a chimera. Furthermore, when some adult chimeras were bred to a black feather line breeder some of the hatched chicks had black feathers. This indicated that donor line reproductive cells had also developed in the chimera. In this study the blood types of the donor and recipient line chickens were evaluated. Subsequently donor blood-types were demonstrated in blood cells of recipient chicks. In chimeras the percentage of blood cells of the donor type was correlated with the percent of black feathers in the plumage, as well as the percent of black chicks produced by a chimera. It was concluded that blood-typing for donor cells is an excellent way to estimate chimerism in chickens. Furthermore, this may enhance the selection of chimeras capable of transmitting donor line traits into another line of chickens.
Technical Abstract: Chimeric chickens are being evaluated as an intermediate for development of transgenic chickens. The transfer of Barred Plymouth Rock (BR) blastodermal cells (BC) into White Leghorn (WL) embryos results in BR to WL chimeras, and some breeder males generate over 30% germ-line transmission (GLT) to offspring based on a feather-color trait. Our objectives were to: 1) identify the MHC (B haplotypes) in resident BR and WL lines, 2) establish that B antigens could be detected and quantified in red blood cells (RBC) of chimeras, 3) establish if there is a correlation in chimeras between percentage of RBC with donor B antigens and percentage GLT, and 4) evaluate if the MHC genotype influences chimera development. RBC agglutination data indicated three B haplotypes are present in each line. B*2-like, and B*19-like genes are unique to the WL line, and B*13-like and B-15-like genes are unique to the BR line, whereas a B*21-like gene is present in both lines. In adult BR to WL, as well as 10-14 day old WL to WL chimeras, donor-type B antigens were detectable and quantifiable on RBC using flow cytometry (FC). In BR to WL chimeras the percentage GLT was significantly correlated with the percentage of RBC with donor B antigen, as well as percentage of black feathers in the plumage. In existing BR to WL chimeras the level of chimerism and GLT was higher in B*21/*21 type recipients, but this was not statistically verified in two prospective studies. We conclude that MHC antigens on RBC can be used for identifying, quantifying and selecting chicken chimeras developed by the transfer of BC.