Using the genetic model of Prague recombinant congenic lines of chickens we found that incompatibility in the B-G region of the major histocompatibility complex (MHC) causes very severe graft-versus-host reaction (GVHR)-associated haemolytic anaemia in newly hatched chickens. Unexpectedly, mild or no signs of this GVH disease are elicited when a recipient chick and an adult donor of lymphocytes are incompatible in the whole B haplotype (B-F/L + B-G regions). On the other hand, the B-G region incompatibility alone (as has been described previously) is not sufficient to produce any GVH splenomegaly in embryos at 14 days of incubation. However, GVH splenomegaly in the donor-recipient combinations with the difference in the whole B haplotype (B-F/L + B-G regions) is significantly greater than in those with the B-F/L region difference only. These results confirm that the B-G region genes of chicken MHC are also involved in the histocompatibility reactions. Furthermore, a new hypothetical model for the structure of the chicken MHC is discussed.

Institute of Molecular Genetics Czechoslovak Academy of Sciences Praha

Cytokine response to the RSV antigen delivered by dendritic cell-directed vaccination in congenic chicken lines

Molecular genotyping of recombinant congenic lines provides evidence for crossing-over within the B-G region of the major histocompatibility complex of the chicken

Tumor induction by the LTR, v-src, LTR DNA in four B (MHC) congenic lines of chickens