Clin Exp Vaccine Res.  2021 May;10(2):141-147. 10.7774/cevr.2021.10.2.141.

Immunogenicity of an inactivated rabies vaccine for animals derived from the recombinant ERAGS strain

• Yang DK
• Kim HH
• Park YR
• Yoo JY
• Park Y
• An S
• Hyun BH

• KMID: 2525801
• DOI: http://doi.org/10.7774/cevr.2021.10.2.141

Abstract

Purpose
The aims of the present study were to evaluate the immunogenicity of an inactivated rabies vaccine based on the ERAGS strain
Materials and Methods
The ERAGS virus propagated in Vero cells was inactivated with 3 mM binary ethylenimine for 8 hours. Three types of inactivated rabies vaccines were prepared to determine the minimum vaccine virus titers. Four further types of inactivated rabies vaccines were prepared by blending inactivated ERAGS with four different adjuvants; each vaccine was injected into mice, guinea pigs, and dogs to identify the optimal adjuvant. The immunogenicity of a Montanide (IMS) gel-adjuvanted vaccine was evaluated in cats, dogs, and cattle. Humoral immune responses were measured via a fluorescent antibody virus neutralization method and a blocking enzyme-linked immunosorbent assay.
Results
The minimum virus titer of the inactivated rabies vaccine was over 10^7.0 50% tissue culture infectious doses (TCID₅₀ values)/mL. Of the four kinds of adjuvants, the IMS gel-adjuvanted vaccine induced the highest mean viral neutralizing antibody (VNA) titers of 6.24 and 2.36 IU/mL in guinea pigs and dogs, respectively, and was thus selected as the vaccine for the target animals. Cats, dogs, and cattle inoculated with the IMS gel-adjuvanted vaccine developed protective VNA titers ranging from 3.5 to 1.2 IU/mL at 4 weeks post-inoculation (WPI).
Conclusion
Our data indicate that cats, dogs, and cattle inoculated with an inactivated rabies vaccine derived from the ERAGS strain developed protective immune responses that were maintained to 12 WPI.

Keyword

Inactivated rabies vaccine; Dog; Cat; Cattle