Serological studies of the H activity of Oh red cells with various anti-H reagents.

Several examples of Oh cells have been investigated with various anti-H reagents. After enzyme treatment of the cells with either papain or neuraminidase, very high titres were obtained, particularly with some preparations of Ulex europeus. Fractionation of anti-H Ulex showed that the anti-H component inhibitable by L-fucose required papain treatment of the Oh cells for optimal activity whereas the component not inhibitable by L-fucose agglutinated preferentially Oh cells treated with neuraminidase. The anti-H lectin Cytisus sessifolius which is not inhibitable by L-fucose gave no reaction with papain-treated Oh cells but reacted well when the Oh cells were treated with neuraminidase. Normal O cells were almost equally well agglutinated by the lectins when treated by either of the two enzymes. That the various lectin components activated by enzymes had H specificity was shown by the fact that their activity was inhibited by purified H substance, partially inhibited to L-fucose and 2-fucosyllactose and not at all by purified Lea substance and non-secretor salivas. In spite of the high titres obtained with Oh cells by the enzyme technique, the amount of H present on the red cells, judged by inhibition tests, in comparison with normal group O cells was very small.