Naja naja oxiana (NNO) is one of the important venomous species in Iran. The current snakebite treatment is antivenom therapy that deals with hyper immunization of horses with crude or fractionated snake venom plus traditional adjuvants, like Freund’s adjuvant. For improvement of antivenom production, it has been suggested to use different adjuvant systems or immunization procedures. In this study, humoral immune responses against immunogenic fractions of NNO venom (NNO3 and NNO4) and crude venom have been compared by usage of different adjuvant and immunization routes. Additionally, a new indirect enzyme-linked immunosorbent assay (ELISA) was set up for the detection of specific antivenom antibodies. This study was conducted on six different groups of female Dutch rabbits that were hyperimmunized using crude and fractionated NNO venom, along with Freund’s and MF59 adjuvants through subcutaneous or intramuscular route. The immunization was performed four times with 10-day intervals and the levels of specific antibodiees were detected by indirect ELISA. The statistical analysis reveals a negligible variation in the antivenom titers among the venom-inoculated groups, regardless of the adjuvant type or the immunization route. Finally, it was concluded that the fractions are efficient for antivenom production, and it is possible to use MF59 adjuvant via subcutaneous routes as an alternative to Freund’s adjuvants considering its fair immunopotentiation capacity and safety in animals.

Foot-and-mouth disease (FMD) has a high prevalence in cloven-hoofed animals. It is also highly contagious and remains a serious threat to livestock worldwide. Despite the widespread vaccination program in Iran, outbreaks of FMD continue to occur. Vaccination is one of the most effective methods of preventing FMD. The vaccines used in Iran are of the inactivated type and contain several serotypes. Since inactivated vaccines without adjuvants do not induce a high and durable antibody response, it is necessary to use adjuvants. Montanide ISA 206 VG is a mineral oil-based adjuvant that produces a water-in-oil-in-water (w:o:w) emulsion in vaccine preparations. However, a large number of manufacturers in Iran and around the world still use alum adjuvant (with or without saponin) to produce the FMD vaccine. This study used Montanide ISA 206 and alum adjuvants to administer the O2010 serotype of the FMD virus to goats. A total of six goats were divided randomly into three groups. Vaccines were administered subcutaneously twice, at a one-month interval. Blood sampling was done at different times, and the micro-neutralization method was used to measure the neutralizing antibody titer in each serum. Seven days after the second vaccination, the alum group’s antibody titer was higher but not statistically significant. However, from the 28th day after the second injection until the end of the study, the Montanide ISA 206 group’s antibody titer was significantly higher than that of the alum group. Six months after the second injection, the antibody titer in the ISA 206 group remained at the peak level, while in the alum group, it decreased and reached the minimum protective level. Nine months after the second injection, the antibody titer remained at its peak level in the ISA 206 group, whereas it dropped significantly in the alum group. Based on the findings, ISA 206 VG is capable of generating long-term humoral immunity in goats against the FMD serotype O2010 and could replace aluminum hydroxide adjuvants in FMD vaccine preparations.

Aluminum-containing adjuvants are extensively used for inactive human and animal vaccines owing to their favorable immunostimulative and safe properties. Nonetheless, there is controversy over the effects of different aluminum salts as an adjuvant for the bovine parainfluenza virus type 3 (BPIV3) vaccine. In order to find a suitable adjuvant, we studied the effects of two adjuvants (i.e., aluminum hydroxide [Al(OH)3] and aluminum potassium sulfate [AlPO4]) on the production of neutralizing antibodies (NAbs) for an experimental BPIV3 vaccine. The animals under study (Guinea pigs) were randomly assigned to five groups of experimental vaccines containing Al(OH)3 (AH), AlPO4 (AP), Al(OH)3-AlPO4 mixture (MIX), commercial vaccine (COM), and control (NS). The treatment groups were immunized with two doses of vaccine 21 days apart (on days 0 and 21), and the control group received normal saline under the same conditions. The animals were monitored for 42 days, and blood samples were then taken. The results indicated that all vaccines were able to induce the production of NAbs at levels higher than the minimum protective titer (0.6). An increase in titer was observed throughout the monitoring period. Moreover, an increase in both the level and mean titer of NAbs obtained from the vaccine containing Al(OH)3 adjuvant was significantly higher than in the other studied groups (P≤0.005). The comparison of NAbs titer in other groups did not display a significant difference. Considering the speed of rising and the optimal titer of NAbs production in the experimental vaccine, the Al(OH)3 adjuvant is a suitable candidate for preparing a vaccine against BPIV3 for immunization.