Immunological Regulation Roles Of Porcine ?-1,4-galactosyltransferase ? (B4GALT5) In PRRSV Infection

Glycosylation plays an important regulatory role in the process of cell transport and adhesion,recognition of immune molecules.Capsular virus after infected cells can potentially compete for glycosylation-modifying enzymes and affect virus assembly and cell functions.B4GALT5(?-1,4 galactosyltransferase V)exists as a family that consists of seven members,which have different chronological expression,receptor specificities,tissue distribution,biological functions,and are closely related to growth of embryos and many serious diseases.Significant upregulation of B4GALT5 occurred in PRRSV-infected 3D4/21 cells by analysis of transcriptome sequencing data.The purpose of this study is to investigate the regulatory role of this enzyme in PRRSV proliferation and cellullar immunologic response,and to understand the relationship between PRRSV and host cells from the perspective of galactosylated modification.The main results are as shown below:(1)Gene cloning and protein characterization analysis: Porcine B4GALT5(pB4GALT5)gene was cloned from porcine alveolar macrophages based on the transcriptome sequencing results of PRRSV-infected 3D4/21 cells.Meanwhile we also predicted domains and potential functions of encoded protein;(2)Effect of porcine B4GALT5 on PRRSV proliferation: Up-regulation of pB4GALT5 expression occurred in PRRSV-infected cells.Moreover,proliferation of PRRSV was inhibited in 3D4/21 cells overexpressing pB4GALT5.The immunofluorescence between pB4GALT5 and envelope glycoproteins of PRRSV showed that pB4GALT5 had a significant co-localization with GP5.Besides,the interaction between pB4GALT5 and GP5 had been detected by co-immunoprecipitation;(3)Immunomodulatory effects of porcine B4GALT5: The expression levels of different immune-related molecules was up-regulated to some extent in PRRSV-infected 3D4/21 cells overexpressing pB4GALT5,including TNF-?,IL-1?,IL-6,IL-18;MHC-I/II;MCP-1 and CCR2;LFA-1,ICAM-1.In summary,studies have shown that pB4GALT5 may play an important role in regulating PRRSV proliferation and glycosylation.pB4GALT5 affects the distribution of GP5 in the Golgi apparatus and membrane transport through interaction and modification of PRRSV-GP5 protein,thus affecting proliferation and assembly of PRRSV At the same time,pB4GALT5 may affect the glycosylation of infected immune cells and further affect the immune function of cells.These results will promote the researches of potential antiviral immune mechanism of ?-1,4-galactosyltransferase V.