The occurrence of materials cross-reacting with anti-A and -B agglutinins in fruit or seed extracts of higher plants.

Fourteen species of higher plants were found to contain materials in their fruit or seed extracts which were heat stable, inhibitory for and capable of absorbing anti-H, -A and -B agglutinins and also lectins. The majority of species exhibiting a high grade of such cross-reactivity belonged to two genera, Viburnum of the Caprifoliaceae and Acer of the Aceraceae. Gel diffusion patterns indicated, however, that the A- and B-like activities of the Viburnum fruits were somewhat distinct serologically from blood group A and B substances of human origin.