The present study was conducted in 33 new horses, randomly divided into four groups and hyperimmunized using crude mixture of snake venoms, viz.; Cobra venom (CV), Russell's viper venom (RV), Krait venom (KV) and Saw-scaled viper (EV) along with four above mentioned adjuvants through subcutaneous (s.c.) route at intervals of two weeks. Periodic standard safety assessments were done. Immunopotentiation ability of each adjuvant group in terms of percent responders were estimated at 14th, 21st, 30th and 43rd week. The neutralization activity (ED50) of pooled sera samples by 43rd week, obtained with IMS 3012 group for CV, RV, KV and EV venoms were 0.133, 0.143, 0.070 and 0.270 mg venom/ml of serum respectively. The antivenom potency with IMS 3012 and overall responding horses (100 % ) even against weak immunogen like CV was significantly higher (p < 0.05) than other three adjuvants studied. The horses of IMS 3012 group showed minimum local reactions at injection site, while horses from other three groups exhibited moderate (++) reactions; 66.7 % in ISA 206, 12.5 % in ISA 35 and 14.3 % in IFA respectively, however these were transient and reabsorbed or healed subsequently.
Finally, we conclude that, nanoparticle adjuvant IMS 3012 could be a possible alternative to the emulsion adjuvants for primary phase of immunization in antivenom preparation considering its better immunopotentiation capacity and safety in donor animals.