EXAMINATION FOR COMPLEMENT-REQUIRING NEUTRALIZING ANTIBODIES AGAINST JAPANESE ENCEPHALITIS, WESTERN EQUINE ENCEPHALITIS AND VACCINA VIRUSES.

The discovery of the complement-requiring neutralizing CRN antibody against herpes simplex virus was of great importance from the viewpoint of diagnosis of infections, because in the natural infection of man by this virus the appearance of CRN antibody preceded that of other antibodies, and also one serum sample was often enough to give positive diagnosis. The specificity of this antibody was also confirmed. Such a simple and quick diagnosis procedure must be advantageous over the conventional serodiagnosis method, which usually requires two serum samples, acute and convalescent, for giving positive diagnosis, especially when the disease under suspicion is an endemic one. These results have pointed to the necessity to examine whether or not a similar antibody response exists in other viral infections. If there is any similarity of immune reaction in other cases, the detection of specific CRN antibody would serve as a useful tool for early diagnosis of those diseases. Therefore, attempts were undertaken to see at first whether this would be the case with Japanese encephalitis, Western equine encephalitis and vaccinia viruses. Author