In vivo properties of attenuated rubella virus, “Cendehill”® strain

Summary

Thein vivo properties of the “Cendehill” strain of attenuated rubella virus were further studied. The absence of seroconversion in rabbits inoculated subcutaneously was confirmed. When the virus was given intravenously most rabbits seroconverted and virus could be recovered from the organs of inoculated animals. Virulent virus given subcutaneously even in minute amounts, regularly evoked antibodies.

When given by the combined intrathalamic, intraspinal and intramuscular routes, the “Cendehill” strain evoked antibodies in about one third ofCercopithecus monkeys in 17 to 19 days. When cortisone was given simultaneously with the virus the seroconversion rate in monkeys inoculated under similar conditions dropped to about 3%. A depressive effect of cortisone on the production of antibodies was also observed when virulent virus or the attenuated RA 27/3 virus were used.

Comparative tests with virulent virus and “Cendehill” virus were also carried out in the following species: rats, mice, ferrets, gerbils and guinea-pigs. They all responded serologically to a single parenteral inoculation of wild virus. Mice, ferrets, gerbils and guinea-pigs failed to seroconvert when inoculated with “Cende-hill” virus. The rat was the only species in which a seroconversion could be regularly obtained.