The haemagglutinating activity of Berne virus.

Berne virus possesses haemagglutinating activity which is inhibited by antisera that neutralize the infectivity of the virus. In decreasing order, human, rabbit and guinea-pig erythrocytes were agglutinated whereas agglutination was not observed with rat, goose, chicken or horse red blood cells. This pattern is different from that seen with the closely related Breda virus of cattle. Haemagglutinin was found to co-sediment with viral infectivity in sucrose density gradients. Transmission electron microscopy showed that intact virus particles form bridges between adjacent erythrocytes. The viral envelope was seen at a distance from the erythrocyte surface suggesting that the peplomers possess haemagglutinating activity. Haemagglutination was decreased in the presence of fetuin and gangliosides and also by pretreatment of the erythrocytes with periodate, suggesting that the virus binds to glycoproteins and/or glycolipids on the erythrocyte surface.