Quantitative analysis of Le(a) and Le(b) antigens in human saliva

We have measured the H type 1, Le(a) and Le(b) antigens in the saliva from 129 Japanese individuals by a time-resolved europium ion fluorometric immunoassay using artificial antigen-albumin complexes as the reference substances. We confirmed that the amount of Le(b) was larger than that of Le(a) in the saliva from secretors (Le(a-b+)) and vice versa in the saliva from nonsecretors (Le(a+b-)). Unexpectedly, we discovered appreciable amounts of Le(b) with small amounts of H type 1 in the saliva from the nonsecretors. The concentration of Le(b) was about 10, 6 and 35% of the concentration of the Le(a) in the saliva from the nonsecretors of the A, B and O groups, respectively. The possible formation of Le(b) from Le(a), in addition to the formation of Le(b) from H type 1, in the salivary glands is discussed.