This study aims to evaluate the immunogenicity of membrane surface protein P4 from Mycoplasmacapricolum subsp. capripneumoniae (Mccp) and its potential as a candidate antigen for vaccine. Preliminary laboratory work identified the membrane surface protein P4. In this study, recombinant protein was prepared using a prokaryotic expression system, after purification, the recombinant protein was emulsified with an adjuvant to prepare vaccine. Immunization and challenge experiments were conducted on goats, and the immune efficacy was evaluated based on clinical symptoms, pathological changes, serum antibodies, bacterial load in lung, and cytokines. The results showed that the rP4 protein was successfully expressed and purified, and could specifically react with the His-tag antibody, rP4 polyclonal antibody and Mccp infection antibody. Immunization with the rP4 stimulated high levels of antibody production in goat but did not alleviate clinical symptoms, with a survival rate of only 40%, the same as the PBS control group. Pathological observations indicated that both acute and chronic cases in the P4 group were more severe than those in the control group. The average bacterial load in the lungs was higher in the P4 group than that in the inactivated vaccine group and the PBS control group. Serum cytokines analysis revealed that the P4 group had upregulated IL-2 level and downregulated IL-4 level post-immunization. In conclusion, this study successfully expressed and purified rP4 and the prepared P4 protein induced antibody production in goats but failed to protect them from Mccp challenge, even exacerbating the pathogenic effects of Mccp on the goats. The findings provide a reference for the design and development of future new type vaccines for contagious caprine pleuropneumonia.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |