Enzymatic conversion of human group O red cells into Group B active cells by alpha-D-galactosyltransferases of sera and salivas from group B and its variant types.

Salivas from group B secretor or non-secretor, acting on O red cells in the presence of UDP-galactose, each converted them into B cells, which were agglutinated against anti-B human serum (1:512) at the titre of thirty-two-fold, while secretor or non-secretor group AB salivas converted O red cells into B active cells, which were agglutinated by anti-B human serum (1:512) at the titre of eight- to sixteen-fold. The results indicate that the alpha-galactosyltransferases which participate in the biosynthesis of group B substance are secreted in group B or AB salivas of both secretor and non-secretor types as well as in their sera. Agglutinabilities of enzymatically converted B-active red cells against anti-B human serum indicate that alpha-galactosyltransferase activities of both serum and saliva from a weak B (Bw) individual, who has weak B antigens in red cells and saliva, were lower than those of normal group B. The alpha-galactosyltransferase activities in group Bm sera were lower than those of normal group B, while the enzyme activities in salivas of group Bm were demonstrated to the same degree in normal group B salivas.