Examination for Complement-Requiring Neutralizing Antibodies Against Japanese Encephalitis, Western Equine Encephalitis Vaccinia Viruses

摘要

Rabbits and guinea pigs were immunized with betapropiolactone-inactivaated Western equine encephalitis (WEE) virus vaccine and complement (C') enhancement of early and late neutralizing antibodies was compared. If the early antibody had shown a greater C' enhancement than the late antibody, it would have been regarded as a good tool for early diagnosis of infection. However, contrary to our previous work, the early and late sera showed the same extent of C' enhancement, which was 2 to 4 -fold throughout. The reason for the discrepancy between the earlier and the present results was explored. Since herpes simplex virus induced early neutralizing antibody which was enhanced by C' in an all-or-none fashion but induced a quick development of the late type antibody after a booster injection, it was thought possible that a virus closely related to WEE virus may have infected the animals previously and resulted in a booster effect. However, the anti-WEE rabbit serum did not contain antibody cross-reactive with a very closely related Sindbis virus even in the presence of C'. It may be possible that the previous vaccine contained some viable virus which induced a response different from that induced by inactivated virus. Alternatively, it may be there are a group of viruses which induce the herpes-type response while other viruses induce the WEE-type response with respect to the extent of C' enhancement of early neutralizing antibody. (Author)