Determination of homozygosity or heterozygosity for the G2m(n) allotype by a monoclonal, precipitating antibody.
Monoclonal antibody SH 21 was found to be a good anti-IgG2m(n) reagent both for the conventional typing (HA inhibition) and for precipitation in polyethylene glycol containing gel. Antibody SH 21, together with monoclonal antibody HP 6014 (anti-IgG2), was used for the discrimination between G2m(+n) homozygotes and heterozygotes in a double diffusion assay, where the two antibodies and a serum sample were placed in corners of a triangle. In the case of a homozygote SH 21 was able to stop the diffusion of IgG2 to a precipitation line, but some IgG2 of a heterozygote was able to diffuse beyond the precipitate, forming a crossed precipitation pattern. The validity of the typing was checked with serum samples from 54 families. All the 33 'obligatory heterozygotes' (G2m(+n) parent(s) of a G2m(-n) child, or the other way round) exhibited the crossed precipitate. The frequency of the G2mn allele in a Finnish population of 297 unrelated adults was 0.409.
Rautonen
N
N
Department of Bacteriology and Immunology, University of Helsinki, Finland.
Seppälä
I
I
Hallberg
T
T
Grubb
R
R
Mäkelä
O
O
D000483:Alleles; D000911:Antibodies, Monoclonal; D005260:Female; D005387:Finland; D005787:Gene Frequency; D005803:Genes, Immunoglobulin; D005819:Genetic Markers; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D005779:Immunodiffusion; D007129:Immunoglobulin Gm Allotypes / Q000235:genetics*; D008297:Male; D011234:Precipitins
D000911:Antibodies, Monoclonal; D005819:Genetic Markers; D007129:Immunoglobulin Gm Allotypes; D011234:Precipitins