Evaluation of cellular and humeral immune response of sheep vaccinated with inactivated Rift Valley Fever vaccine adjuvanted with Montanide Gel

Abstract

Rift Valley Fever (RVF) is an acute infectious zoonotic arthropod - born viral disease, affecting many species of animals with causing great economic losses in animal wealth. Vaccination of susceptible animals with RVF vaccines are an important factor for controlling the disease. This study was applied to improve the locally produced vaccine by using Montanide Gel 01™ as an adjuvant in comparison with Aluminium Hydroxide inactivated RVF vaccine, through evaluating the humeral, cellular immune response and the duration of immunity in sheep vaccinated with the prepared vaccines. The antibody titre in the group vaccinated with one dose of Montanide Gel 01TM inactivated RVF vaccine reached the protective level at the 7th-day post-vaccination and stayed within the protective level till the end of the 11th month, while in the group vaccinated with 2 doses, the antibody titre stayed within the protective level till the end of 13th month in sheep vaccinated with the same vaccine. These results revealed that the best vaccine is 20% Montanide Gel 01TM inactivated RVF vaccine (2 doses) as it gave a higher level of antibody throughout the experiment compared with that of other vaccinated groups. Also, the results of cell-mediated immune response showed that: (i) The cell proliferation expressed by optical density showed early significance in sheep vaccinated by Montanide Gel 01TM inactivated RVF vaccine and a slight elevation in sheep vaccinated by Aluminium Hydroxide inactivated RVF vaccine. (ii) The phagocytic activity expressed by phagocytic percentage and phagocytic index showed early significant in sheep vaccinated with Montanide Gel 01TM inactivated RVF vaccine and a slight elevation in sheep vaccinated by Aluminium hydroxide inactivated RVF vaccine. Also, high levels of IL-6 and IL-12 gene expression were detected in sheep vaccinated with Montanide Gel 01TM inactivated RVF vaccine as shown by RT-PCR. All the previous data showed that the Montanide Gel 01TM was highly immunogenic than Aluminium Hydroxide beside that Montanide Gel 01TM inactivated RVF vaccine induces rapid onset immunological response with a long duration which recommended for emergency vaccination.

Keywords

• gene expression
• interleukine (il)
• real-time polymerase chain reaction (rt-pcr)
• rift valley fever (rvf)
• sheep