The Preliminary Study Of Duplex Subunit Vaccine Combined With PCV2 Cap Protein And PPV VP2 Protein

The diseases of Porcine parvovirus type 2 and Porcine circovirus are major diseases that influence the pig industry in the world.The coinfection of PPV and PCV2 is widespread,and PPV can obviously promote the occurrence of PCV2 related diseases and aggravate the severity of the clinica.At present,immune the singel vaccine of PPV and PCV2 with oil adjuvant are the major strategy to prevent these diseases.However,there is not only the problem of biological safety and side reaction,but also the shortcomings of the stress reaction and the poor level of cellular immune response.Therefore,it is significance that design a kind of duplex vaccine which is safer and more efficient.In this study,on the basic of the function and characteristics of PPV and PCV2 related genes were analyzed,we designed to truncate the sequence of NLS signal peptide that affected the expression of Cap protein.The truncated Cap protein gene sequence and the complete VP2 gene sequence were obtained.These two proteins were successfully expressed by the Escherichia coli expression system,and the concentration was 1213 mg/mL of Cap protein,1025 mg/mL of VP2 protein after purification.They possessed better immunoreactivity identified by SDS-PAGE and western-blotting.In addition,the Cap protein and VP2 protein were emulsified with the Montanide ISA201 adjuvant,which can induce the cellular immune response.Otherwise,we established the mouse model of coinfection by PPV and PCV2.The immune test of guinea pigs and piglets were carried out.The results proved that the subunit vaccine could induce the good humoral and cellular immune response.The antibody titer of duplex subunit vaccine was not lower than that of single vaccine.There was no immunosuppressive effect after emulsification about PPV VP2 protein and PCV2 Cap protein.The successful design of this study proved that PPV VP2 protein and PCV2 Cap protein can be expressed by the Escherichia coli expression system,and the subunit vaccine of Cap protein and VP2 protein emulsified with the Montanide ISA201 adjuvant can make up the defects of singel vaccine with oil adjuvant,which can induce the good cellular immune response and humoral immune response.It lay the foundation for the development of duplex subunit vaccine.