Hemagglutinins in marine algae.

We surveyed the Japanese marine algae for hemagglutinins with rabbit erythrocytes. Algae used in this screening were 53 species; 6 species of green algae, 42 of red algae and 5 of brown algae. The results showed the presence of the active components with strong activities in 14 species; 4 species of the green algae, 9 of the red algae and 1 of the brown algae. The extracts of the algae which gave positive results were further examined for hemagglutinating activity against other erythrocytes of animals and human A, B, O and AB groups. Of the 14 species positive to hemaggutination with rabbit erythrocytes, 5 species showed no hemagglutinating activity with human erythrocytes. The results also inticated that the extract of a green alga Ulva arasakii reacted preferentially with erythrocytes of human A and O groups, and that those of both a green alga Bryopsis hypnoides and a red alga Laurencia undulata showed more specific activities with human B erythrocytes than with the others. There were no marked features in the distribution of the hemagglutinins among marine algae tested.