Efficacy of Montanide (IMS 3015) as an adjuvant for an inactivated Rift Valley fever (RVF) vaccine in sheep.

This study was conducted to evaluate an adjuvant, Montanide (IMS 3015), in improving the quality of Rift Valley fever (RVF) vaccine relative to the traditional adjuvant, aluminum hydroxide gel. Vaccinated sheep were evaluated using biochemical analysis, kidney function tests, liver function tests, and immunological tests. Sheep vaccinated with Montanide (IMS 3015) adjuvant showed significantly higher total protein, total globulin, and gamma globulin concentrations from the second week until the fifth month than the controls. Conversely, albumin concentration and the A/G ratio significantly decreased during this period. Kidney function and liver function tests revealed no differences among any of the groups. There was a significant increase in lymphocyte proportion and a decrease in neutrophil proportion in sheep vaccinated with the Montanide (IMS 3015) adjuvant. Lymphocyte cell proliferation was significantly different in sheep vaccinated with the Montanide (IMS 3015) adjuvant from that in controls. Neutralizing indices were significantly higher in sheep vaccinated with the Montanide (IMS 3015) adjuvant than in controls. The current study showed that sheep vaccinated with inactivated RVF virus with Montanide (IMS 3015) as an adjuvant were protected and no pathological symptoms or biochemical changes were detected. Moreover, the vaccine induced rapid onset of immunological responses with long durations unlike inactivated RVF vaccine with aluminum hydroxide gel.