Abstract
The author has obtained the following results through his study of HVJ (type sendai) conducted in the manner described below in comparison with influenza A (PR 8).
The growth of HVJ (type Sendai) on Zinsser's agar slant and in Maitland's culture flask (with chorioallantoic membrane) was thoroughly followed in terms of HA and EID50, and the virus was cultured successively generation after generation on Zinsser's agar slant and was investigated on its infectivity to eggs and mice as well as on its hemagglutination titers in order to reveal the changes in the nature of the virus particles. 1) HVJ can be multiplied on Zinsser's agar slant and moreover, it can be successively cultured generation after generation. But a clear distinction observed between this virus and PR 8, is the fact that its HA negative periode is considerably longer than PR 8, especially when they were inoculated in a small quantity. 2) Both, HVJ and PR 8 cultured on Zinsser's agar slant fall in EID50 titer and rise in HA titre in their first generation when inoculated in a large quantity. Consequently the ratio of EID50 to HA drops considerably.
In view of these facts, it is clear that this culture contains many noninfectious virus particles. But it cannot be easily determined whether this virus particle is premature, incomplete or inactivated in natures IT seems probably that this is incomplete in its first stage of culture (2 to 3 days), whereas it will be mixed with inactivated virus particles in the last stage (4 to 5 days). 3) As mentioned above, HVJ cultured on Zinsser's agar slant contains many non infectious particles in the first generation. But if it is successively cultured generation after generation at an interval of two to three days, it becomes to possess a nature of a complete virus with rising EID50, with comparatively lower HA and with the ratio of I to H being kept between 5-6. 4) The pathogenicity against mice of HVJ cultured generation after generation on Zinsser's agar slant is considerably lower in comparison with that of the egg passage virus even if their egg infective titers were kept in an almost epual values. 5) When cultured by Maitland, s method with chorioallantoic membrane as its culture tissue, HVJ was quite different either from influeuza A or B and was rather similar to NDV so far as their multiplication behaviour is concerned, because its latent period was considerably longer.
