Effects Of African Swine Fever Virus On Immune Proteasome Subunit LMP2

African swine fever(ASF)is an acute and febrous infectious disease caused by African swine fever virus(ASFV)in domestic pigs and wild boars,which seriously affects the economic development of the countries and regions where ASF occurs.The purpose of this paper is to study ASFV infection in pigs for swine major histocompatibility complex(SLA)class I and II molecules expression level,the influence of ASFV protein and the interaction between immune protease subunits,in order to further analysis of ASFV caused by immune escape provide basic data and other application research.(1)A 90 day healthy landwhite pig was artificially infected with ASFV,after 0,1,3,5 and 7days of infection,the pigs were euthanized and the spleen macrophages were isolated.The expression of SLA-I/II molecules on the surface of spleen macrophages was detected by flow cytometry;At the same time,bone marrow macrophages were isolated from 90 day healthy landlocked pigs after euthanasia,and the expression of SLA-I/II molecules on the surface of bone marrow macrophages was detected after they were infected with ASFV for 24 hour.The results showed that ASFV infection significantly down-regulated the expression of SLA-I class molecules in spleen macrophages in vivo(P<0.01),and had no significant effect on the expression of SLA-II molecules(P>0.05);In vitro,ASFV infection significantly down-regulated the expression of SLAI class molecules in bone marrow macrophages(P<0.01),and had no significant effect on the expression of SLA-II molecules((P>0.05).The results suggest that ASFV infection in pigs has a certain effect on SLA in vitro and in vivo.(2)The effect of ASFV infection on immune proteasome activity of BMDM and i PAM cells was detected by elisa.The effects of ASFV on the expression of immune proteasome subunit in spleen macrophages were investigated.The results showed that the activity of immune proteasome in BMDM and i PAM cells was significantly inhibited after infection with ASFV(P<0.01).The expression of immune proteasome subunits LMP2 and LMP10 was significantly inhibited in spleen macrophages infected with ASFV at the transcriptional level on day 7(P<0.05),significantly inhibited the expression of immune proteasome subunits LMP2,LMP7 and LMP10 at protein level.The results indicated that ASFV infected pigs had significant effects on the activity and subunit of immune proteasome.(3)The optimal induction dose of IFN-γ was screened by Western Blot;The expression of IFN-γ induced immune proteasome subunit was detected after infection with ASFV;Screening and verifying the expression of ASFV proteins that affect IFN-γ induced immune proteasome subunits;The interaction between ASFV protein and IFN-γ induced immune proteasome subunit was screened by immunoprecipitation assay.The results showed that IFN-γ significantly increased the activity of immune proteasome subunits at 3 μg;All the selected ASFV proteins could be expressed,and the ASFV protein B475 L inhibited the expression of IFN-γ induced immune proteasome subunits LMP2,LMP7 and LMP10;B475L interacts directly with IFN-γ induced immune proteasome subunit LMP2.In conclusion,by studying the influence of ASFV infection on the expression level of SLA class molecules in immune cells and the interaction between immune protease,it was revealed that ASFV protein B475 L can directly interact with IFN-γ induced immune proteasome subunit LMP2,down-regulated SLA-I expression was involved in immune evasion,the results provided basic information for further study of the cellular immune mechanism of ASFV and the development of new vaccines.