Section 11 — Immiinogenetics 



three loci. The genetic potential of sires with 

 regard to egg white protein types was inferred 

 by pedigree analyses. Blood types of all birds 

 were determined by saline agglutination tests 

 employing specific blood-typing reagents made 

 by iso-immunization within each inbred line. 

 Linkage analyses of egg white protein types and 

 blood types were made on data from two 

 generations and part of a third generation. No 

 evidence was found for close linkage between the 

 A and B blood groups and the three loci con- 

 trolling the egg white protein variants. 



1. Nature 189, 981. 1961. 



2. Brit. Poultry Sci. 3, 161. 



1962. 



11.16. Effects of B Locus Genotype on Immunological 

 Tolerance in Fowl. L. W. Schifrman and 

 A. W. Nordskog (Ames, U.S.A.). 



Similarity of the B blood group locus in 

 chickens with the H-2 locus in mice has previous- 

 ly been established. Techniques employed to 

 study immunological tolerance were similar to 

 those of workers using birds of unknown histo- 

 compatibility relationships except that B geno- 

 type was determined by blood typing. Of 70 B 

 compatible skin transplants exchanged between 

 closely related chicks at 17 days of age only 

 three were rejected prior to 34 days post-grafting. 

 All of 47 transplants between B incompatible 

 birds were rejected early; median survival time 

 (MST) being 6.6 1 0.4 days. Survival time of 47 

 transplants between B incompatible birds 

 injected at hatching with erythrocytes of the 

 same B incompatibility did not differ signifi- 

 cantly (MST 6.8 i 0.5 days) although the bird's 

 ability to produce B hemagglutinins at 3 months 

 of age was markedly reduced. Neonatal injection 

 of donor-type leukocytes was relatively effective 

 in inducing tolerance to later B incompatible 

 transplants. In a subsequent experiment injection 

 of erythrocytes at hatching and leukocytes at 

 17 days induced a greater degree of tolerance to 

 B incompatible transplants, exchanged on the 

 27th day, than did injection of leukocytes at 

 17 days only. Of interest was the fact that 

 heterozygous B incompatible transplants re- 

 mained intact significantly longer than homo- 

 zygous B incompatible transplants; presumably 

 an effect of differences in concentration of 

 foreign B antigens at the cell surface. Partial 

 tolerance existed in some cases such that a 

 homozygous incompatible (e.g. fl'/fi 1 ) transplant 

 was rejected early while a heterozygous incom- 

 patible (e.g. B l 'B 2 ) transplant on the same 



individual (eg. B 2 /B 2 ) showed no apparent 

 rejection during the bird's lifetime. 



11.17. Genetics of Rabbit 7S y-globulins. S. Dray, 

 J. E. Colberg, G. O. Young, L. Gerald 

 ( Bethesda, U.S.A.), and A. Nisonoff (Urbana, 

 U.S.A.). 



Isoantibodies identify several rabbit y-globulin 

 allotypic specificities which are heritable. Analy- 

 sis of progeny confirm the hypothesis that the 

 Al, A2 and A3 allotypic specificities are deter- 

 mined by three autosomal allelic genes at the 

 a locus; the A4 and A5 specificities, by two 

 autosomal allelic genes at the b locus. Progeny 

 tests show that the a and b loci are not closely 

 linked. An allotypic specificity P is determined at 

 a third locus. Using I 181 -labeled y-globulins, 

 molecules with Aal, Ab4 and Ab5 specificities 

 were estimated quantitatively by repeated 

 precipitations with antibody. In the Ab4 or 

 Ab5 homozygotes or the Ab4-Ab5 heterozygote, 

 80-90 per cent of the y-globulin-I 131 molecules 

 have Ab4 or Ab5; 10-20 per cent of the y- 

 globulin molecules have neither Ab4 nor Ab5. 

 In the Ab4-Ab5 heterozygote, the quantities of 

 y-globulin molecules precipitable by anti- 

 Ab4 (64 percent) or anti-Ab5 (27 per cent) are 

 independent of the order of precipitation indi- 

 cating that allelic specificities Ab4 and Ab5 are 

 not found on the same y-globulin molecules. 

 However, cellular studies of lymph nodes, using 

 anti-A4 and anti-A5 conjugated with fluorescein 

 isothiocyanate or lissamine rhodamine B, show 

 that allelic specificities Ab4 and Ab5 are found 

 within the same cell. Aal, Ab5 and Aa3, Ab4 

 double homozygous rabbits were mated and 

 y-globulin from a doubly heterozygous offspring 

 tested: 68 percent of the molecules with Aal also 

 had Ab4; 16 per cent of the molecules with Aal 

 also had Ab5 specificity. If, as is probable, non- 

 allelic specificities are present on different 

 polypeptide chains, the data are consistent with 

 random assortment of non-allelic chains in 

 molecules of the offspring. 



11.18. Immunogenetics of Rabbit y-globulin. 



A. S. Kelus and P. G. H. Gell (Birmingham, 

 Great Britain). 



There are known six (Al, A2, A3, A4, A5 

 and A6) allotypes of rabbit y-globulin dis- 

 tinguishable serologically. 



The inheritance of all six allotypes has been 

 studied in nearly 100 matings with several 



194 



