STUDIES ON THE IMMUNOLOGICAL OVERLAP AMONG CERTAIN ARTHROPOD-BORNE VIRUSES. II. THE ROLE OF SEROLOGIC RELATIONSHIPS IN EXPERIMENTAL VACCINATION PROCEDURES

Abstract

In vitro neutralization tests, as well as hemagglutination-inhibition and complement-fixation antibody studies have indicated that certain arthropod-borne viruses are immunologically related. Four such viruses that appear to be rather closely related are West Nile (WN), St. Louis encephalitis (ST.L.), Murray Valley encephalitis (MV), and Japanese B (JB) encephalitis viruses. It has been shown by others that monkeys infected with St. L. virus and then with Ilheus virus, which is also related to the above group, developed not only St. L. neutralizing antibodies and Ilheus neutralizing antibodies but also JB and WN neutralizing antibodies. Human beings, given live WN virus and then live Ilheus virus, formed JB neutralizing antibodies after infection with Ilheus virus. Work in this laboratory has involved using a live virus of low virulence, combined with an injection of a killed vaccine of a related, virulent virus in order to produce a good antibody response against certain of the arthropod-borne viruses against which good vaccines have not as yet been prepared. The data described in this paper present further evidence for the possibility of using in humans a live WN virus in combination with one injection of killed JB virus to protect against several related virulent viruses of the group B classification. The difficulties of using such a vaccination scheme are also presented.