Preliminary Assessment of Newly Developed Escherichia coli Mastitis Vaccines in Laboratory Animals: Promising Results
Preliminary Assessment of Newly Developed Escherichia coli Mastitis Vaccines in Laboratory Animals: Promising Results
Saira Jabeen1, Muhammad Avais1*, Jawaria Ali Khan1, Kamran Ashraf2, Aftab Ahmad Anjum3
ABSTRACT
Escherichia coli is recognized as an environmental mastitis pathogen and a significant contributor to clinical mastitis cases in dairy cows. Due to environmental nature of this pathogen, conventional mastitis control measures often prove ineffective. Hence, the endeavor to combat E. coli mastitis through vaccination appears feasible and economically prudent. This study was aimed at preparation and evaluation of mastitis vaccines prepared by using local E. coli isolate, bearing the aggR gene, derived from mastitis cases in dairy cows. Prior to embarking on vaccine preparation, the immunogenicity of this E. coli (aggR) strain was determined across various concentrations in a cohort of 20 locally bred rabbits. For preparation of vaccines, the antigen concentration was adjusted to 10^10 cells/mL, a level determined to trigger highest IHA antibody response in rabbits. Three distinct vaccine types were prepared, each employing different adjuvants. To ensure the quality and safety of these vaccines, quality control assessment was carried out. The efficacy evaluation of the vaccines was performed on 24 locally bred rabbits, divided into 4 groups. Each group received a different type of vaccine, with booster doses at 15-day intervals following the priming. Serum samples were collected biweekly over a 60-day period, and the antibody titers were measured using IHA test. Geometric mean titers (GMT) were computed and subsequently analyzed statistically. The results indicated that the E. coli (aggR) isolate exhibited immunogenicity in rabbits, with the antigen concentration of 10^10 cells/mL yielding highest antibody titers. Vaccines demonstrated sterility and safety, exhibiting no adverse effects when administered to laboratory animals. Furthermore, upon comparing the effectiveness of the vaccines, it became evident that the Montanide-adjuvanted vaccine elicited significantly higher antibody titers (P<0.05) in comparison to the plain vaccine or the aluminum hydroxide-adjuvanted vaccine. Challenge protection assay revealed that Montanide and aluminum adjuvanted vaccines had 100% survival rate among rabbits compared to 16.7% of placebo group. It was concluded that newly developed E. coli (aggR) mastitis vaccines have promising results to combat E. coli mastitis in dairy cows.
Novelty Statement | This research presents a novel approach to combating E. coli mastitis in dairy cows through the development and evaluation of newly formulated vaccines. The findings offer a significant advancement in mastitis vaccine development, shedding light on potential strategies to mitigate the economic burden of mastitis in the dairy industry.
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