Evalution Of Immunoprotective Effects Of Microneme Protein 3 And Microneme Adhesive Region Protein Of Eimeria Acervulina,Eimeria Maxima And Eimeria Mitis

Chicken coccidiosis is a kind of poultry disease which is great harm to the breeding,There are seven common chicken coccidia,including E.acervulina,E.praecox,E.maxima,E.necatrix,E.mitis,E.brunetti and E.tenella.Among them,E.acervulina and E.praecox mainly parasitize in the front part of the small intestine,E.maxima and E.necatrix mainly parasitize in the middle part of the small intestine,E.mitis and E.brunetti mainly parasitize in the back part of the small intestine,and E.tenella mainly parasitizes in the cecum.Preliminary research in the laboratory found that the microneme(MIC)secreted by the microneme of the apical complex plays a key role in the invasion of host cells by chicken coccidia.It was also found that the different microneme adhesive regions(MAR)of the MIC3 protein have different ability to bind to the host cell during the invasion process of the worm,which may be the key molecule for the invasion of the host cell by the worm.Therefore,this study compared the immunoprotective effects of Eimeria acervulina,Eimeria maxima,and Eimeria mitis MIC3 protein and its main MAR on coccidia infection,and further clarified the MIC3 protein and its MAR.It provides a basis for its role in the process of parasite invasion and lays a foundation for the construction of new vaccines using recombinant MAR protein.After prokaryotic expression and purification,the recombinant MIC3 protein of Eimeria acervulina was obtained in this experiment,and the domain proteins with the strongest and weakest binding ability to small intestinal epithelial cells,MAR3 and MAR6,the recombinant MIC3 protein Em MIC3 and the recombinant domain proteins MAR2 and MAR5 of Eimeria maxima,the recombinant MIC3 protein EmiMIC3 and the recombinant domain proteins MAR4 and MAR5 of Eimeria mitis.Recombinant proteins were injected intramuscularly and polyclonal antibodies were injected intravenously to evaluate the immune protective effects of tthese proteins against.Through intramuscular injection of recombinant protein and wing intravenous injection of polyclonal antibodies;detection of serum Ig Y antibody levels,and recording of weight gain,oocyst reduction rate,intestinal lesion scores,etc.to calculate the anti-coccidial index(ACI)to evaluate its immune protection.The immunization results showed that Ea MIC3,MAR3 and MAR6 can all increase the level of antigen-specific Ig Y antibodies;in the recombinant protein immunization group,the ACI of MIC3 and MAR3 were 178 and 165,respectively,while the ACI of MAR6 was 130;in the recombinant protein antiserum immunization group,The ACI of MIC3 and MAR3 are 179 and 166,respectively,while the ACI of MAR6 is 158.The above results indicate that compared with the control group,both MIC3 and MAR3 have obvious immune protection effects,and their weight gain effects are particularly prominent.It is suggested that MAR has a certain immune protection effect,which can block the invasion of coccidia,so as to achieve the effect of resisting coccidia infection.The immunization results showed that all of them can increase the level of antigen-specific Ig Y antibodies;the recombinant protein immunization group was injected into the leg muscles Among them,the ACI of MIC3 and MAR2 were 180 and 170,respectively,and the ACI of MAR5 was 137;in the wing intravenous injection of recombinant protein antiserum immunization group,the ACI of MIC3 and MAR2 were 180 and 164,respectively,and the ACI of MAR5 was 137.The above results indicate that compared with the control group,both the recombinant protein immunization group and the recombinant protein antiserum immunization group have better immune protection effects,and the weight gain effect is particularly obvious.It is suggested that MAR may play a better immune protection ability by blocking the coccidia invasion process.The results showed that immunization with EmiMIC3,MAR4,and MAR5 can all increase the level of antigen-specific Ig Y antibodies;in the recombinant protein immunization group,the ACI of MIC3 and MAR4 were 172 and 164,respectively,while the ACI of MAR5 was 153;in the recombinant protein antiserum immunization group,The ACI of MIC3 is 183,and the ACI of MAR4 and MAR5 are 153 and 142.The above results indicate that in the two immunization methods,compared with the control group,MIC3 and MAR4 have immunoprotective effects,and the increase in weight gain is particularly obvious,suggesting that MAR is in the process of coccidial parasitism by playing a role in blocking the invasion.Cut off the effect,provide a certain degree of immune protection.The experimental results show that MAR3 in Em MIC3 has a better immune effect,MAR2 in the domain protein of Em MIC3 has a better immune effect,and MAR4 in EmiMIC3 has a better immune effect.Among the three kinds of coccidia,MAR,which has a strong ability to bind to intestinal epithelial cells,has a certain immunoprotective effect,while MAR with weak binding ability has a weaker immune protective ability.The above results indicate that the immunoprotective effect of MAR is consistent with its ability to bind to intestinal epithelial cells,which further proves the key role of these MARs in the process of coccidian invasion,and also provides a basis for subunit vaccine antigen screening.