Preparation of high-titred antisera for sigma virus strains from Hawaii and France and their use in neutralization tests in vitro and in vivo.

Antisera were prepared in rabbits against two strains of sigma virus, from France and Hawaii respectively, using purified virus from cell cultures. All antisera had the same titre by immunofluorescence, 1/400 or 1/800, whether tested against the homologous or the heterologous virus. An antiserum prepared with the French strain neutralized the Hawaiian virus at a dilution of 1/800 both in vitro and in vivo. The Hawaiian virus was not neutralized to a significant extent by reference mouse ascitic fluids for 26 different vertebrate rhabdoviruses.