Chaudhuri Pallab, Saminathan Mani, Ali Syed Atif, Kaur Gurpreet, Singh Shiv Varan, Lalsiamthara Jonathan, Goswami Tapas K, Singh Ashwini K, Singh Sandeep K, Malik Praveen, Singh Raj K
Division of Bacteriology and Mycology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243122, India.
Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243122, India.
Vaccines (Basel). 2021 Dec 2;9(12):1423. doi: 10.3390/vaccines9121423.
Vaccination of cattle and buffaloes with strain 19 has been the mainstay for control of bovine brucellosis. However, vaccination with S19 suffers major drawbacks in terms of its safety and interference with serodiagnosis of clinical infection. S19∆, a perosamine synthetase B gene deletion mutant, overcomes the drawbacks of the S19 vaccine strain. The present study aimed to evaluate the potential of S19Δ vaccine candidate in the natural host, buffaloes. Safety of S19∆, for animals use, was assessed in guinea pigs. Protective efficacy of vaccine was assessed in buffaloes by immunizing with normal dose (4 × 10 colony forming units (CFU)/animal) and reduced dose (2 × 10 CFU/animal) of S19Δ and challenged with virulent strain of S544 on 300 days post immunization. Bacterial persistency of S19∆ was assessed in buffalo calves after 42 days of inoculation. Different serological, biochemical and pathological studies were performed to evaluate the S19∆ vaccine. The S19Δ immunized animals showed significantly low levels of anti-lipopolysaccharides (LPS) antibodies. All the immunized animals were protected against challenge infection with S544. Sera from the majority of S19Δ immunized buffalo calves showed moderate to weak agglutination to RBPT antigen and thereby, could apparently be differentiated from S19 vaccinated and clinically-infected animals. The S19Δ was more sensitive to buffalo serum complement mediated lysis than its parent strain, S19. Animals culled at 6-weeks-post vaccination showed no gross lesions in organs and there was comparatively lower burden of infection in the lymph nodes of S19Δ immunized animals. With attributes of higher safety, strong protective efficacy and potential of differentiating infected from vaccinated animals (DIVA), S19Δ would be a prospective alternate to conventional S19 vaccines for control of bovine brucellosis as proven in buffaloes.
用19号菌株对牛和水牛进行疫苗接种一直是控制牛布鲁氏菌病的主要手段。然而，接种S19疫苗在安全性以及干扰临床感染的血清学诊断方面存在重大缺陷。S19∆是一种过胺合成酶B基因缺失突变体，克服了S19疫苗株的缺点。本研究旨在评估S19∆候选疫苗在自然宿主水牛中的潜力。在豚鼠中评估了S19∆用于动物的安全性。通过用正常剂量（4×10菌落形成单位（CFU）/动物）和降低剂量（2×10 CFU/动物）的S19∆免疫水牛，并在免疫后300天用强毒株S544进行攻毒，评估疫苗的保护效力。在接种42天后评估S19∆在水牛犊牛中的细菌持续性。进行了不同的血清学、生化和病理学研究以评估S19∆疫苗。接种S19∆的动物显示出极低水平的抗脂多糖（LPS）抗体。所有免疫动物均受到保护，免受S544的攻毒感染。大多数接种S19∆的水牛犊牛血清对RBPT抗原显示中度至弱凝集，因此，显然可以与接种S19疫苗和临床感染的动物区分开来。S19∆比其亲本菌株S19对水牛血清补体介导的裂解更敏感。接种疫苗6周后扑杀的动物器官未出现明显病变，接种S19∆的动物淋巴结中的感染负担相对较低。S19∆具有更高的安全性、强大的保护效力以及区分感染动物和接种动物（DIVA）的潜力，如在水牛中所证实的，它将是控制牛布鲁氏菌病的传统S19疫苗的一种有前景的替代品。
