Human IgG Allotypes Co-Occurring in More than One IgG Subclass

Abstract

Inheritance of an excess of immunoglobulin allotypes in one haplotype was encountered which could not be explained by the assumption of a duplicated locus. The surplus of allotypes was related to markers on the CH3 domain of y3 chains. Two such cases were investigated extensively. The IgG3 molecules were isolated by gel filtration and by absorption on protein A. Only the usual combination of allotypes appeared to be present on the IgG3 molecules. The supernumerary markers were found in one case on IgG2 molecules and in the other case on IgG 1 molecules. This followed from investigations of eluates after separation of the subclasses by immune absorptions. A hypothesis was proposed to explain these events by mutation of a particular position of an otherwise homologous stretch of y-subclass DNA.

The genetic diversity of three peculiar populations descending from the slave trade: Gm study of Noir Marron from French Guiana

“…All the plasma were tested for G1m (1,2,3,17), G2m (23), G3m (5,6,10,11,13,14,15,16,21,24) and Gm (28) immunoglobulin allotypic markers by using a classical haemagglutination inhibition method [36]. The reagents used are described by Dugoujon et al [37] and Giraldo et al [38].…”

“…The notation ".." indicates that the sample was tested for G2m (23) but found to be negative for this allotype, and 5 * stands for 5, 10, 11, 13, 14. Gm (28) is presented separately from the other polymorphisms because it has been shown that it is not necessarily located on the gamma 3 chain in African populations [24].…”

“…Gm allotypes are encoded by IGHG genes that are closely linked on chromosome 14 (14q32.33) and are inherited [15]. Data on Gm allotypes of human immunoglobulins in African populations and other populations have been previously reported [16][17][18][19][20][21][22][23][24]. The Gm system has been frequently studied in human populations, due to its heterogeneous haplotype frequencies among populations [25][26][27], and is thus very useful to assess genetic relationships among populations in a given geographic area [28][29][30] or from different geographic areas [23,31,32].…”

Definition of the RFLP alleles in the human immunoglobulin IGHG gene locus

“…Blood samples (20)(21)(22)(23)(24)(25) Hybridizations were carried out at 42 "C overnight in 5 x SSPE (5 x saline sodium phosphate EDTA; 0.9 M NaC1, 50 mM NaH2P04, pH 7.4, 5 mM EDTA, pH 7.4), 50% formamide supplemented with 0.5% SDS, 0.2% Ficoll 400, 0.2% bovine serum albumin (BSA), 0.2% polyvinylpyrrolidone, 5% dextran sulfate, 50 pg/ml sonicated, denatured salmon sperm DNA, and 10 ng/ml of the labeled, heat-denatured probe. The probes were labeled with 32P-dCTP by nick translation [22] at a specific activity of 0.5 x lo8-1 x lo8 cpmlpg.…”

Gene conversion in human immunoglobulin γ locus shown by unusual location of IgG allotypes

“…Converted yl and 72 genes with y3 sequences A few years ago, we demonstrated the occurrence of some human Gm allotypes in more than one subclass [24,32]: the Gm (g5 and v) antigenic determinants, usually located on the CH3 domain of y3 chains (33-351 ( fig.l), were found on 71 chains encoded by an unusual GZrna~gS*v*z yl gene.…”