Characterization of a monoclonal antibody that neutralizes the hyaluronidase activity of Russell's viper venom.

Three monoclonal antibodies (WPN1, WPN2 and WPN3) raised against a partially purified fraction of Russell's viper venom (RVV) were characterized. All three monoclonal antibodies reacted with crude RVV when tested by ELISA, but only two (WPN1, WPN2) neutralized its hyaluronidase activity. WPN1 was the more potent and was effective at an antigen: antibody ratio of 1:3. Furthermore, WPN1 was shown to recognize only the 14,000 MW component of crude RVV. This has been identified in a previous study to be hyaluronidase. This antibody was also found to recognize some components of Calloselasma rhodostoma venom which also possesses potent hyaluronidase activity. The potential therapeutic role of antibodies that neutralize the hyaluronidase component of snake venoms should be investigated further.

Effect of inosiplex on the humoral and cell-mediated immune responses to intradermal human diploid cell rabies vaccine.

Antigen-stimulated lymphocyte transformation was studied in recipients of intradermal human diploid cell rabies vaccine (HDCV). HDCV was administered intradermally at 8 different anatomical sites, 0.1 ml each, on day 0; followed by another 4-site injection on day 7. Rabies antigen-stimulated in vitro proliferative response was evident as early as 7 days after starting immunization. It reached a peak on day 14 and had declined by day 28. The cellular proliferative response preceded and roughly correlated with the antirabies antibody response. Simultaneous administration of inosiplex, an antiviral and immunopotentiating drug, during the first 10 days of intradermal HDCV immunization did not result in heightened antibody titres or cell-mediated immune response to the vaccine. The number of T cells and the lymphocyte proliferative response to phytohaemagglutinin in inosiplex-treated vaccinees were similarly not significantly different from untreated controls. Our results confirm other previous findings that a specific cell-mediated immune response can be consistently and rapidly induced by an intradermal regimen of HDCV immunization. The addition of inosiplex to this regimen did not enhance the humoral or cell-mediated immune responses to the vaccine. The apparent lack of immunostimulating effect of inosiplex in this setting may be the result of several factors such as the immunization schedule and the immunologic parameters examined.

Lack of interferon induction in man by two rabies tissue culture vaccines.

Both neutralising antibody and interferon play a part in protection of animals against death from rabies virus infection. Interferon induction was therefore sought in 53 volunteers within 24 hours of receiving human diploid cell strain vaccine or fetal bovine kidney cell vaccine given either intramuscularly or intradermally. Repeat observations were made in 18 subjects following a second dose of vaccine seven days later. No interferon was detected in any sample tested although no subject had any detectable rabies neutralising antibody on day 0. The sensitivity of the interferon assay, and comparison with other studies are discussed. An interferon inducer suitable for human use should be sought as an alternative to, or a replacement for, passive rabies immunization.