[Passive hemagglutination test for Semliki-Forest Virus (author's transl)].

Several methods of coupling immunoglobulins onto sheep erythrocytes have been examined with a view to demonstrate Semliki-Forest virus by use of a passive hemagglutination tests. With the exception of the carbodiimid coupling reaction, most methods could be used to couple goat anti SFV IgG to erythrocytes. Best results were obtained when anti SFV goat IgG was coupled to sheep red blood cells by using 0.25% glutaraldehyde. Sheep red blood cells treated after that method could be used to identify as well as titrate SFV in any given solution. The actual mode of agglutination was made visible by electron microscopy in so far as SFV was found to form dimers of adjacent erythrocytes via a bridge formation. The passive hemagglutination offers considerable advantages compared to other methods such as the direct hemagglutination with goose erythrocytes, as formalin inactivated virus can be detected therby. The described test therefore offers an additional approach to check the potency of inactivated togavirus vaccines.