The genetic control of gammaG1-heavy chains was investigated by taking advantage of two recently described genetic antigens, Gm(z) and Gm(y), both produced by heteroimmunization of rabbits with myeloma proteins. These were studied in conjunction with known genetic markers, Gm(a) and Gm(f). The results indicated that among Caucasians there are two major allelic genes, Gm(za) and Gm(fy), coding for distinct varieties of gammaG1-heavy chains. Each of these contains a pair of genetic antigens which are located on different fragments of the chain and can be separated by enzymatic splitting with papain. The different areas of the heavy chains appear to be under the control of the same gene. In Mongoloid populations a grouping of three genetic antigens, Gm(f), (y), and (a), was found on isolated myeloma proteins and normal gamma-globulins indicating the presence of a Gm(fya) gene. The possible genetic events leading to the contrasting Caucasian and Mongoloid genes are discussed. In the gamma-globulin system the occurrence of multiple genetic antigens in different positions of the same heavy chains is the general rule. A better understanding of the relationships between the genes for the gammaG1-subgroup to those for the gammaG2- and gammaG3-subgroup has been obtained through the use of the multiple genetic markers. Strong evidence was obtained for intergenic crossover mechanisms to explain racial differences in the relationships of these genes as well as certain unusual gene complexes found through family studies. Further evidence was obtained for mapping the closely linked genes for the three subgroups in a specific order.

Black or African American↗

PubMed1967

Studies of the Vi (gamma-2c) subgroup of gamma-globulin. A relationship between concentration and genetic type among normal individuals.

Further delineation of the antigens characteristic of the Vi or gamma(2c) subgroup of gamma-globulin was carried out utilizing a number of rabbit and primate antisera. Two genetic antigens characteristic of this subgroup, Gm(b) and Gm(g), were also detected by precipitation techniques with certain of the antisera. These were clearly differentiated from antigens common to all proteins of this subgroup. The concentration, of Vi protein in normal and pathological sera from several population groups was measured quantitatively utilizing a variety of immunological procedures. All sera studied showed measurable levels. The mean value for Caucasian sera was 1.06 mg/ml, representing approximately 8% of gammaG-globulin. This agreed closely with a figure of 8.4% for the incidence of myeloma proteins of the Vi subgroup among all gammaG-myeloma proteins in Caucasians. A relationship was found between the Vi subgroup concentration and the specific genetic type of a given individual. Measurements of the Gm(b) genetic determinants, which are found solely in Vi-type proteins, brought forward this relationship. Gm(b+) individuals showed higher concentrations of Vi-type gamma-globulin than those who were Gm(b-), and this difference was statistically significant for both the homozygous and heterozygous states. It appeared that the structural genes for Gm(b+) polypeptide chains showed a greater synthetic capacity than those for Gm(b-) types. The possible significance of such effects in governing the relative composition of the antibody population in a given individual is discussed.

Black or African American↗

PubMed1967

The relationship between the Inv (1) and (2) genetic antigens of kappa human light chains.

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Antigens↗

PubMed1966

Genetically determined antigen of the Ne subgroup of gamma-globulin: detection by precipitin analysis.

A genetic antigen, Gm(n), has been described for the Ne subgroup of gamma-globulin previously devoid of Gm factors. It was detected by precipitin tests with a primate antiserum to Ne-type heavy chains. A relation to the Gm(b) antigens of the Vi subgroup and the Gm(f) and Gm(y) antigens of the We subgroup was apparent. The availablity of genetic antigens for the heavy chains of three subgroups of gamma-globulin with varying relationships in different populations offers an approach to the mapping of the genes concerned.

Antigens↗

PubMed1966