title: Competition between ABO and Le gene specified enzymes. I. A Lewis related difference in the amount of A antigen in saliva of A1 and A2 secretors.
abstract: Radioimmunoassays were prepared using two anti-A and one anti-B reagents. The specificity of the procedures was assessed with 13 artificial antigens. The amounts of A and B natural antigens in saliva of ABH secretors of known Lewis phenotype were measured with these assays. The results confirmed that the average amount of A antigen is lower in Lewis-positive (Leb) than in Lewis-negative (Led) donors and in A2 than in A1 donors. However, the differences among the four combined A and Lewis phenotypes were only supported by significantly lower amounts of A antigenic determinants in A2Leb as compared to the other three phenotypes (A1Leb, A1Led and A2Led) that had similar amounts of A antigenic determinants. No Lewis-related difference could be detected in the amounts of B antigens between BLeb and BLed donors. The results are discussed in terms of competition between A, B and Lewis-gene-specified enzymes for their common acceptors. The difference in the efficiency of the A2 enzyme as compared to that of the A1 enzyme is proposed as a possible explanation for the A1-A2 phenotypic difference.
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics*; D000939:Epitopes; D005796:Genes; D006801:Humans; D007106:Immune Sera; D007202:Indicators and Reagents; D007983:Lewis Blood Group Antigens / Q000235:genetics*; D010641:Phenotype; D011863:Radioimmunoassay; D012463:Saliva / Q000276:immunology
chemical_list: D000017:ABO Blood-Group System; D000939:Epitopes; D007106:Immune Sera; D007202:Indicators and Reagents; D007983:Lewis Blood Group Antigens