NSP Antibody Production Rules Of Swine After FMDV Infection And Its Interacted Proteins Identification In Serum

Foot-and-mouth disease(FMDV)is a severe infectious disease of cloven-hoofed animals caused by FMDV.FMDV belongs to the genus of picornavirus acanthus virus and except for the viral capsid,which is mainly composed of structural proteins(SP)of viral proteins(VP)1 to 4,and also includes L,2A,2B,2C,3A,3B,3C,3D,their precursors and other non-structural proteins(NSP).NSP participates in the replication of viruse,the cleavage of polyproteins,and assembly of viral particles.Animals infected with FMDV can produce both SP and NSP antibodies.Vaccine-immunized animals mainly induce product of SP antibodies.Therefore,NSP is used as an antigen to detect NSP antibodies in animals to distinguish FMDV-infected animals and vaccinated animals has been obtained.It has been widely recognized that the earliest detection time of NSP antibodies is decisive significant in the prevention and control of FMD.NSP can interact with serum proteins,and the interacts may also be composed of substrates or molecular components regulated by the target protein.Recognizes a given protein’s interacts protein can provide information about the function of the protein and the clues of the molecular mechanism its involved.At present,the FMDV diagnostic kits on the market is cluttered,the earliest appearance time of immunoglobulin after animals infected with FMD and the interaction protein between NSP and pig serum is still unclear.In this paper,three different kits were used to detect the serum levels of IgA,IgM and IgG of pigs artificially infected with FMDV to obtain the changes at different time points of different immunoglobulins and the earliest appearance time of antibody;3AB was used as bait protein.The protein of 3AB and its interact protein of FMDV-NSP positive pig serum was identified by immunoprecipitation combined with mass spectrometry,and its protein function was analyzed.The results showed that the kit A most suitable for FMDV NSP antibody detection,and found that FMDV NSP IgG first appeared on the 5th day,IgA,IgM content began to rise gradually after 3 days of FMDV infected,Ig M showed the highest content on the 3rd day when the body was attacked by FMDV.Serum IgA content showed a gradual rising trend in 3rd days.Eighty-one proteins of 3AB interact with FMDV-positive NSP serum were identified by co-immunoprecipitation combined with mass spectrometry.They were mainly involved in response to stimuli,biological regulation,immune system response,and regulation of biological processes through GO analysis.It mainly concentrated in extracellular regions,organelles,extracellular regions,cells,and certain parts of cells,and participate in combine binding,structural molecular activities,molecular function regulators,catalytic reactions,and signal transduction activities.Through KEGG Pathway analysis,it was found that the interact proteins screened were mainly involved in Staphylococcus aureus infection,PI3K-Akt signaling pathway and other signal pathways.In this study,We detect the NSP antibody in the serum of pigs infected with FMDV,and obtained the earliest appearance time and different time points of different immunoglobulins appearance rule,which can provide a scientific basis for further research on the replicaction of foot-and-mouth disease virus and the earliest appearance time of FMDV NSP antibody.The interacted protein with NSP were obtained by co-immunoprecipitation combined with mass spectrometry,it can provide a scientific basis for the replication and regulation of FMDV in pigs.