Improving mccp vaccine in sheep: novel strategies for development, efficacy and cross-protection

Vaccination serves as a straightforward and efficient method for preventing numerous infectious diseases in animals. One such disease is contagious caprine pleuropneumonia (CCPP), a severe lung ailment affecting small ruminants. This research aimed to create a vaccine utilizing Mycoplasma capricolum subsp. capripneumoniae (Mccp) isolated from KPK, Pakistan. The local Mccp strain was rendered inactive alongside saponin, a substance, to produce the vaccine. The viable count of Mycoplasma mycoides subsp. capripneumoniae (Mccp) was determined to be 1x108 CFU/mL from the stock culture, with an estimated protein content of 0.2g/ml. The developed vaccine underwent testing and comparison with a standard CCPP vaccine in sheep to assess safety and efficacy. Twelve experimental sheep were divided into three groups: A, B, and C. Group A received the new vaccine, group B received the standard vaccine, and group C acted as the control. Groups A and B were further split into two subsets: one remained healthy while the other fell ill. The sheep were closely monitored for any changes over a 75-day post-vaccination period. Blood samples were analyzed for antibodies, showing average antibody GMT titers of 24.3, 84.4, and 128 on days 21, 28, and 35 post-immunization. By day 35, sheep vaccinated with the new vaccine displayed the highest antibody levels. The quadratic relationship (R2) indicated that both saponized and lyophilized vaccines were influenced by the number of days by 57.4% and 55%, respectively. The new vaccine demonstrated superior efficacy in sheep compared to the standard vaccine, with saponin playing a role in its effectiveness. The study successfully deactivated Mycoplasma mycoides subsp. capripneumoniae cells with autoclaved saponin, ensuring a sterile vaccine. In vivo testing in rabbits confirmed the vaccine's safety, while serum analysis in sheep revealed protective antibody responses, with the saponized vaccine eliciting higher titers than the lyophilized version. These findings suggest the potential efficacy of the saponized vaccine against Mccp infection