An Alternative Inactivant for Rift Valley Fever Virus using Cobra Venom-derived L-Amino Oxidase, which is Related to its Immune Potential

ABSTRACT Vaccine improvement depends on the formulation, adjuvant type and inactivant used. The type of formulation may interfere with immunogenicity. The present work aimed to evaluate the inactivation activity and related immune potential of the Cobra venom-derived LAO enzyme compared to the currently used inactivants (BPL and formalin) for both animal and human vaccines. The RVF virus was completely inactivated within 6 hrs, 4 hrs and 2 hrs after treatment with Formalin, LAO and BPL, respectively. The vaccine potency [ED50] was arranged in a descending order from formalin (0.016) to BPL (0.005) and LAO (0.002). The total IgG levels, Neutralizing Index (NI) and Interferon levels were significantly increased compared to those detected after immunization with the BPL- and Formalin-inactivated vaccine candidates