Studies on Japanese B Encephalitis Virus Vaccines from Tissue Culture

Summary

Twenty-four volunteer terminal cancer patients, not recently treated in any manner to increase susceptibility to viral infection or inhibit antibody response were injected with an experimental lot of live attenuated OCT-541 24°C line of Japanese B encephalitis virus prepared as a vaccine for human use. They were observed clinically for signs of possible disease and for oncolysis, and a long series of serum specimens was checked in the laboratory for viremia and a variety of antibody responses. Twenty-three patients survived long enough for the desired observations.

None showed any recognizable sign of disease from the virus. One patient with clinically diagnosed (not biopsy proven) carcinoma of the rectum developed low grade viremia on days 10 and 12, developed excellent antibody response and his tumor disappeared. One other appeared to have a similar but less confirmable viremia, but no significant antibody or oncolytic response occurred. All other patients, including 9 with proven carcinoma of the rectum, failed to respond with oncolysis, viremia or antibodies of any type.

Two patients were given multiple injections with adequate follow-up and one of these responded with antibody, the other (2 injections, the first i.v.) did not.

It is concluded that this “cold” attenuated virus strain is probably too attenuated to infect and produce antibody as a result of replication in normal man, as had been shown to be the case previously in many other mammals with higher body temperatures, including other primates. No further human volunteer testing of this live virus preparation is planned for antibody response or oncolysis.