Section 1 1 — Immunogenetics 



ones 18.3 U./ml, the sera of the hybrid animals 

 contained 48.3 U./ml of properdin. These re- 

 sults suggest that immunobiological titres are 

 determined by genetic factors, and heterosis 

 effects may occur in them, though it seems to be 

 evident by the results of the author's other in- 

 vestigations that environmental factors (such as 

 exposure to cold) can change the degree of 

 immunity within a comparatively short period. 



11.28. Histocompatibility and Linkage Relationships 

 of Loci Determining Isoantigens of the Rat. 



Joy Palm (Philadelphia, U.S.A.). 



Histocompatibility and linkage relationships 

 of genes determining cellular antigens in three 

 inbred rat strains (Lewis, N.B. and W.I.F.) are 

 being investigated. Allelic genes determine two 

 red cell antigens, 1 of Lewis and 3 of B.N. 11 ' 

 The histocompatibility function of the locus was 

 indicated by the rapid (under 12 days) rejection 

 of Lewis or B.N. grafts on Fo hybrids which 

 always occurred when donor and host were 

 incompatible for these antigens. W.I.F. strain 

 rats lacked antigens 1 and 3 but did possess 

 an antigen with the B specificity. The segrega- 

 tion ratios in backcross tests indicated that the 

 genes determining antigens 1 and 3 were allelic 

 with the gene for the B antigen, but were trans- 

 mitted independently of sex and the non-anti- 

 genic loci for albinism and hooding. Tests for 

 linkage with other mutant genes are in progress. 

 The C-D antigenic locus, defined by Owen 

 (loc. cit.), was not associated with histocompati- 

 bility reactions even with the exchange of tissue 

 grafts between inbred rats differing only for 

 these antigens. The locus was not obviously 

 sex-linked or linked to loci controlling albinism, 

 chocolate coat color and hooding, or to the 

 locus determining antigens 1 and 3. A search 

 is being made for evidence (either by linkage 

 relationships or serological cross-reactivity of 

 specific antisera) indicating an homology of the 

 antigenic loci with those of the mouse. 



1. Palm, N. Y. Acad. 97, 1962 



2. Bogden and Aptekman, loc. cit . 



11.29. (D.) Genetics of the Anaphylactoid Reaction in 

 Rats. H. Kalmus, J. M. Harris and G. B. 

 West (London, Great Britain). 



A single injection of dextran or egg white 

 produces hyperemia, pruritis and oedema in the 



face, ears and paws of most laboratory rats. 

 This reaction resembles an anaphylactic reac- 

 tion, but no prior sensitization is necessary. 

 Rats which do not react in the described way 

 even after repeated injections were found in some 

 Wistar albino colonies and pure strains of 

 reactors and non reactors were bred. The dif- 

 ference appears to be caused by a recessive auto- 

 somal gene dx which in the homozygous state 

 prevents the reaction; Dx dx and Dx Dx animals 

 are reactors. The gene was outbred into other 

 strains and segregates independently of the fur 

 colour genes c, b and a. In 14 colonies of dif- 

 ferent origin non-reactivity occurred in 3 Wistar 

 strains at frequencies of 17.5, 23.4 and 100 per 

 cent. Two of these colonies were maintained by 

 brother sister matings and the third as a closed 

 population. 



J. M. Harris, H. Kalmus and G. B. West, 

 Genetical control of the anaphylactoid reaction 

 in rats. Genetical Research 1963 (in press). 



11.30. New Crossreacting Hetero- and Iso-antigenic 

 Systems in Serum of Mammals including 

 Man. J. Moor-Jankowski and K. S. Brown 

 (Bethesda, U.S.A.). 



On the basis of our previous results on gene- 

 tically controlled variations in serum isoantigens, 

 a working hypothesis was established for experi- 

 mental determination of antigenic markers in 

 animal sera. Experiments were performed in 

 (1) closely related species, e.g. monkeys and 

 man, and in (2) inbred strains of mice. 



(1) Numerous selective antisera produced 

 recognized polymorphisms of several serum 

 components in isologous, and in closely related 

 species. A system of notation was developed to 

 define the antigen antibody relationships between 

 the antigen donor, the antibody producer, and 

 the reacting propositus: I, isogenic iso-antibodies 

 (ii). II, isogenic heteroantibodies (ih); III, 

 heterogenic isoantibodies (hi) (still hypothetical); 

 IV, heterogenic isospecific heteroantibodies 

 (hih); and V, heterogenic heteroantibodies 

 (hh). The abbreviations are used to classify the 

 following experimental results. 



Individual human isoprecipitating antisera 

 recognized polymorphisms in serum lipopro- 

 teins and gamma-globulins of (ii) man and of 

 (ih) Papio cynocephalus, and yet undefined 

 serum polymorphism in (ih) Macacus rhesus. 



Individual isoprecipitating antisera of Papio 

 cynocephalus recognized polymorphisms in se- 

 rum lipoproteins and gamma-globulins of 



198 



