Development of a VirB12 gene-deleted Brucella abortus A19 strain as a vaccine candidate for differentiating infected from vaccinated animals in cattle and establishment of a differentiating ELISA assay.
Feng Ye, Xiaojing Ma, Liya Liu, Wenxi Gu, Qi Zhong, Xinping Yi, Yingyu Liu
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引用次数: 0
Abstract
Objective: To evaluate the application of a VirB12 gene-deleted Brucella abortus A19 strain (A19-ΔVirB12) as a vaccine for differentiating infected from vaccinated animals in cattle and to develop an indirect ELISA (i-ELISA) for serological differentiation between vaccinated and naturally infected animals.
Methods: A total of 115 Holstein cattle were immunized with A19-ΔVirB12 vaccine at 6 X 1010 CFUs, and sera were collected at 15, 30, 60, 90, 120, 150, and 180 days after vaccination. To determine the optimal threshold, serum from 180 infected cattle and 204 cattle immunized with A19-ΔVirB12 vaccine were confirmed positive for brucellosis tested by serum agglutination tests and a commercial ELISA kit. A differential identification i-ELISA was assembled and tested.
Results: The results showed that the Brucella antibody titers peaked at 15 days after immunization with a positive rate of 100%. The titers then continued to decrease over time until 180 days after immunization, when the positive rate was approximately 6.67%. No adverse reactions were observed in the herd after immunization. The differentiating i-ELISA kit had good differential efficiency to distinguish Brucella-positive antibodies induced by immunization with A19-ΔVirB12 vaccine from natural infection, with a sensitivity of 98.9%, specificity of 94.6%, positive predictive value of 94.2%, negative predictive value of 99%, and accuracy of 96.6%.
Conclusions: Application of A19-ΔVirB12 vaccine and differential identification kits would support brucellosis control and eradication efforts in dairy herds.
Clinical relevance: This study demonstrates that the application of A19‑ΔVirB12 vaccine and its differential identification kit in dairy farms can effectively distinguish infected animals from immunized, which support brucellosis control and eradication efforts.
期刊介绍：
The American Journal of Veterinary Research supports the collaborative exchange of information between researchers and clinicians by publishing novel research findings that bridge the gulf between basic research and clinical practice or that help to translate laboratory research and preclinical studies to the development of clinical trials and clinical practice. The journal welcomes submission of high-quality original studies and review articles in a wide range of scientific fields, including anatomy, anesthesiology, animal welfare, behavior, epidemiology, genetics, heredity, infectious disease, molecular biology, oncology, pharmacology, pathogenic mechanisms, physiology, surgery, theriogenology, toxicology, and vaccinology. Species of interest include production animals, companion animals, equids, exotic animals, birds, reptiles, and wild and marine animals. Reports of laboratory animal studies and studies involving the use of animals as experimental models of human diseases are considered only when the study results are of demonstrable benefit to the species used in the research or to another species of veterinary interest. Other fields of interest or animals species are not necessarily excluded from consideration, but such reports must focus on novel research findings. Submitted papers must make an original and substantial contribution to the veterinary medicine knowledge base; preliminary studies are not appropriate.
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