Section 11 — Immunogenetics 



1. The possibility of closely linked genes each 

 controlling one single antigenic factor. 



2. The assumption of series of multiple alleles 

 of which each member produces one anti- 

 genic complex. 



The data on blood groups in cattle as collected 

 in the U.S. and in Europe have contributed 

 largely to the second assumption as the blood 

 groups were usually found to be composed of 

 serologically closely related antigenic factors. 



The blood grouping work in cattle, as per- 

 formed by now in more than 20 laboratories all 

 over the world, has as a result of this been based 

 upon this assumption of multiple alleles of which 

 each is controlling one antigenic complex. 



During the last decade several authors have 

 drawn attention to irregularities by taking this 

 assumption into consideration. 



Recent studies in Holland including over 

 8000 parentage cases are indicating that the 

 assumption of non-crossover units each control- 

 ling a part of the blood groups on the loci 

 controlling the B- and C-groups are presenting 

 a more satisfactory explanation for the inherit- 

 ance of the blood groups in these systems. 



11.13. Possible Somatic Recombination in Twin 

 Cattle with Erythrocyte Mosaicism. W. H. 



Stone, Janis Friedman, Audrey Fregin and 

 Joan Caulton (Madison, U.S.A.). 



About 90 per cent of dizygotic cattle twins 

 contain a mixture of two antigenically distinct 

 kinds of blood cells derived from genetically 

 different tissues. This condition is known as 

 erythrocyte mosaicism (chimerism) and presuma- 

 bly results from an anastomosis of embryonic 

 membranes in utero followed by a reciprocal 

 exchange of primordial erythropoietic tissues. 

 Chimeric twins are immunologically tolerant to 

 erythrocyte and to transplantation antigens of 

 their co-twins. Recent observations indicate 

 that the proportion of the two kinds of cells in 

 co-twins is not constant, suggesting that a twin 

 may lose tolerance for the antigens of the co- 

 twin. In 6 sets of twins tested over a period of 

 years there was evidence of a shift in the propor- 

 tion of the two kinds of cells to a predominant 

 type. In addition, one surviving twin of a set 

 showed a shift toward a "recombinant" cell 

 type containing blood group factors that were 

 previously unique to each of the two original 

 types. This recombinant type represents over 

 95 per cent of the erythrocytes and may have been 

 associated with an abrogation of tolerance. We 

 have sub-lethally irradiated one member of 

 each of 4 pairs of chimeric twins, the other 



serving as a control, to determine if there are 

 changes in the proportion of the two cell 

 types and if "recombinant" types appear. At 10 

 weeks post-irradiation, only 3 of the irradiated 

 twins have survived, but there were no definite 

 changes in their bloods. 



11.14. Production and Effects of Antileukemic 

 Globulins from Animals pretreated with Normal 

 Human Blood. B. Sekla (Prague, Czechoslo- 

 vakia). 



Immunogenetic conception of the origin of 

 malignant cells through somatic mutation and 

 thus acquisition of distinctive antigenic proper- 

 ties of these cells led to trials at production of 

 specific immune sera by biological means; the 

 principle of acquired immunological tolerance 

 (or lowered reactivity) towards antigens applied 

 during early ontogenesis and in large amounts, 

 has been exploited for this aim. 



Pretreatment of new-born sheep was made 

 with large doses of whole human blood mixed 

 from many normal donors. Later, the pretreated 

 and control sheep were immunized with human 

 leukemic cells, every patient having his own 

 experimental and control group of animals. 



In vitro tests have shown that immune sera 

 from pretreated animals do not agglutinate 

 erythrocytes of normal persons as well as those 

 of the patient in question in any considerable 

 measure. Furthermore, these sera have in vitro 

 a relatively specific cytotoxic effect against the 

 leukemic cells in question. 



First trials in vivo have shown that relatively 

 large doses of immune globulins, produced by 

 ammonium sulfate fractionation of immune sera, 

 did not alter the red blood cell count of the 

 patient. Indications of specific effect upon the 

 white blood cell count which have been obtained, 

 must be considered cautiously in connection 

 with previous other therapy. 



11.15. Independence of Genetic Variants of Egg White 

 Proteins and Blood Group Alleles of the A and 

 B Systems of the Chicken. G. R. J. Law 



(Johnston, U.S.A.). 



Egg whites obtained from hens of six inbred 

 lines of chickens were subjected to starch-gel 

 electrophoresis. Variations were observed in 

 three regions corresponding to those reported 

 by Lush d) and by Baker and Manwell ( 2 >. No 

 one line of chickens exhibited segregation of 

 each of the genes controlling the variants at all 



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