Protection against virulent Brucella spp. by gamma-irradiated B. ovis in BALB/c mice model

Purpose: Brucella spp. is a zoonosis that causes undulant fever in humans and abortion in livestock worldwide. Lately, it was conveyed that vaccines developed by irradiation have induced a strong cellular and humoral immune response which have made these types of vaccines highly effective. Materials and Methods: In this study, we aimed to use the gamma-irradiated B. ovis as a vaccine and to study the humoral immune response and cytokines production in order to evaluate it for protecting mice against B. abortus 544, B. melitensis 16M, and B. ovis. Results: The humoral immune response in immunized mice with gamma-irradiated B. ovis showed a lasting for 8 weeks after immunization. Moreover, immunoglobulin G (IgG), IgG1, IgG2a, and IgG2b isotypes antibodies against B. oviswere observed after 4 and 8 weeks of the last immunization. It was noticed that the production of tumor necrosis factor-alpha, interferon-gamma, and interleukin (IL)-10 continued after 4 and 8 weeks by splenocytes from immunized BALB/c mice, while no production of IL-4 or IL-5 was observed. Conclusion: Our results indicate that the protection of BALB/c mice against B. melitensis 16M, B. abortus 544, and B. ovis was induced and the developed vaccine at our laboratory could stimulate similar protection to those induced by the traditional vaccine.