Study of the nature of A1- and A2-antigenic differences with use of monoclonal antibodies: a role of glycoprotein and glycolipid epitopes in their formation

摘要

The author used of A1- and A2-red blood cells to absorb Workshop-IV monoclonal reagents (anti-A1 2-24, 2-25, 2-27; anti-A 2-4, 2-10, 2-28; anti-H 2-71, 2-74) and anti-AHP protection, inhibited them with protein glycoconjugates (Apr), obtained by treating red blood cells with trypsin at pH 6.6 and by separating the supernatant on anion-exchange columns, and with lipid glycoconjugates (Alp), obtained by isolating glycosphingolipids from the trypsin-pretreated red blood cell membranes by the chloroform-methanol method and by subsequently performing anion-exchange gel chromatography. Judging from the results of the absorption using A1- and A2-red blood cells, the antigenic spectrum of A1 is more complete and exceeds that of A2, which permitted the use of the uniform test system of glycoconjugates from A1-red blood cells. Unlike monoclonal antibody's anti-A, the anti-A1-reagents were inhibited more slightly by glycolipid conjugates (other than those of the alkaline type (A1p-0), elution area pH 8.0-8.2), but more strongly by glycoprotein conjugates of the alkaline and moderately acid types (Apr-) and Apr-1 elution area pH 7.9 and 7.1) and they also reacted with the acid type of glycoprotein and glycolipid conjugates (Apr-3 and A1p-3 elution area pH 6.5-6.7). The use trypsin-treated A1-test-red blood cells dramatically decreased the titer of anti-A1-antibodes and failed to reveal the inhibitory activity of Apr-glycoconjugates. The difference in the inhibition of antibodies by glycoconjugates of various types, as well as the selectivity in the responsiveness of anti-A1-antibodies are attributable to the fact that A2-red blood cells show attenuation of not only glycosphingolipid epitopes of the alkaline types (A1p-0), but also glycoprotein epitopes of the acid type (Apr-3) in particular.