Wang JL, Bu RE, Wu JH, Xi LGW, Chen JL, Sun LJ, Wang H. Immunizing mice using different combination antigens of the PI-2a fimbria subunit of
Streptococcus agalactiae.
IRANIAN JOURNAL OF VETERINARY RESEARCH 2019;
20:199-203. [PMID:
31656525 PMCID:
PMC6811712]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 01/29/2019] [Accepted: 02/10/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND
Streptococcus agalactiae is the main causal pathogen of bovine mastitis (BM), causing considerable economic loss to the dairy industry worldwide. Vaccines against S . agalactiae play an important role in preventing disease.
AIMS
The aim of this study was to evaluate the immunoprotection of S. agalactiae pilus island fusion proteins, ancillary protein 1-ancillary protein 2 (AP1-AP2), ancillary protein 1-bone protein (AP1-BP), bone protein-ancillary protein 2 (BP-AP2), and ancillary protein 1-bone protein-ancillary protein 2 (AP1-BP-AP2) in Balb/c mice.
METHODS
Four kinds of fusion antigens and the same volume of Freund's complete adjuvant were mixed vigorously to prepare fusion antigen immuno-samples. The mice were immunized 4 times (on the 0th, 7th, 14th, and 28th days) with these samples with an immunizing dose of 50 g/mouse. After the 4th immunization, serology tests were used to evaluate the antibody. The antibody titre produced by AP1-BP-AP2 fusion antigen was the highest, at up to 1:25600. The mice were then injected with 0.5 ml of 2 × 104 CFU/ml clinically isolated S. agalactiae at day 50 and observed daily for the following 7 days.
RESULTS
Statistical analyses showed that these 4 kinds of fusion antigens had good protective immunity. Among them, AP1-BP-AP2 fusion antigen had the best protective immunity in Balb/c mice, with an immune protection index (PI) of 80%. Conclusion: This research provides a reliable theoretical basis for screening candidate antigens of the subunit vaccine and detecting antigen preparations of S. agalactiae.
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