[Suitability of monoclonal reagents for antigen determination in T-antigen activation]

The lack of additional antibodies--for example anti-T--which can be contained in test sera of human origin has been pointed out as an advantage of monoclonal reagents in blood group serology. It was the aim of our study to examine whether the reactions of monoclonal reagents are nevertheless disturbed by T activation of red blood cells or not.

Monoclonal reagents of several manufacturers of the specificities anti-A, -B, -AB, -A1, -H, -C, -c, -D, -E, -e, -K, -Jka, -Jkb, -Lea, -Leb, -M, and -N were tested. For this study we examined sialidase-treated and not treated red blood cells with and without the tested blood group antigen by the reagent using the tube centrifugation method.

We found no significant disturbances for the monoclonal reagents of the AB0-system, A subgroups, Rhesus system, Kidd system, Kell antigen, and Leb antigen. Monoclonal anti-M and anti-N showed missing reactivity with sialidase-treated erythrocytes, which is already known from polyclonal test sera. Most of the monoclonal anti-Lea reagents showed strong false-positive reactions with T-positive Le(a-) erythrocytes. After several absorptions of one of the monoclonal anti-Lea reagents with T-activated Le(a-b-) red blood cells, the reactivity of the reagent with the Lea antigen and the T antigen had disappeared.

In contrast to the other monoclonal reagents for most of the monoclonal anti-Lea reagents the lack of additional anti-T antibodies does not indicate the lack of false-positive reactions. This cross-reactivity might be caused by the fact that the type 1 chain antigen Lea and the type 3 chain antigen T have the same terminal saccharide (galactose) in beta 1-->3 connection to the preterminal saccharide of their peripheral core structure.