Loss Of Core Fucosylation Suppressed The Humoral Immune Response In Salmonella Typhimurium Infected Mice

BackgroundThe humoral immune response is pivotal to protect the host from Salmonella typhimurium(S.typhimurium)infection.Previously,we found that Core fucosylation catalyzed by Core fucosyltransferase(Fut8)could regulate the immune responses.However,the role of Core fucosylation during S.typhimurium infection remains unclear.ObjectiveIn order to address the role of Core fucosylation in the S.typhimurium infection,in the present study,we tested the hypothesis that Fut8 is involved in controlling salmonella infection in vivo and explored the role of Core fucosylation in regulating the production of antibodies specific for S.typhimurium.MethodsHeterogeneous Fut8+/-OT-? mice were generated by crossing Fut8+/-and OT-? mice,the homozygous wild-type Fut8+/+OT-? and Fut8-/-OT-? mice on the C57BL/6 background were obtained by crossing heterozygous Fut8+/-OT-? mice(C57BL/6).S.typhimurium infection with 1×106 CFU of S.typhimurium for 21 days,sera and spleens from the Fut8+/+ and Fut8-/-mice were harvested(n=6,each group).Extract of intestinal mucus from intestine regions was obtained,the amount of sIgA in intestinal extract was measured by enzyme-linked immunosorbent assay(ELISA).To determine the effects of Fut8 during S.typhimurium infection,we isolated SPLs from Fut8+/+ and Fut8-/-mice post S.typhimurium infection.Anti-S.typhimurium Abs-secreting lymphocytes was analyzed by enzyme-linked immune spot(ELISPOT).The population of SPLs from Fut8+/+and Fut8-/-mice after S.typhimurium infection were compared using Flowcytometric Analysis(FACS)PCR Array was carried to simultaneously examine the mRNA levels of genes associated with the T and B cell activation.The Fut8 products,Core-fucosylated N-glycans,are confirmed by LCA blot,.To determine the role of Fut8 in the CD4+T cell associated immune response CD4+T,DCs and B cells were positively isolated with anti-CD4 Ab,anti-CD11c and anti-CD45R Ab magnetic beads(MACS magnetic cell sorting).To determine whether Fut8 deficiency affects the T-DCs interactions,the communication of CD4+T cells and DC was observed by Confocal Microscopy.ResultsThe Fut8 products,Core-fucosylated N-glycans,are strongly expressed in the Fut8+/+mice SPLs,while the Core fucosylation was ablated in Fut8-/-mice SPLs.The effect of Core fucosylation during S.typhimurium infection,Fut8+/+and Fut8-/-.mice were gavaged with S.typhimurium during the S.typhimurium infection,Fut8-/-mice showed decreased body weight compared to Fut8+/+mice.The level of antiserum specific for S.typhimurium was significantly lower in Fut8-/-mice than Fut8+/+ mice,and the frequency of IgG-producing cells was significantly reduced in Fut8-/-SPLs.Core fucosylation is required for the production of antiserum against S.typhimurium.,After S.typhimurium infection,loss of Core fucosylation suppressed the mRNA expression of T and B cell activation-related genes during S.typhimurium infection.Moreover,loss of Fut8 decreased the induction of Th2-type cytokines from splenic cells of Fut8-/-mice during S.typhimurium infection.In addition,we found that the Core fucosylation regulated the interaction between B and T cells in the lipid raft formation.Fut8 deficiency contributes to attenuated T-B cell communication during S.typhimurium infection,however,no significant difference in CD4+ T-DCs contact was found between Fut8+/+ OT-II and Fut8-/-OT-II mice cells.Compared to Fut8+/+mice Cecum,the number of S.typhimurium is significantly increased in Fut8-/-mice Cecum.Loss of Core fucosylation suppressed the sIgA production specific for S.typhimurium,ConclusionIn the present study,for the first time,we revealed that Core fucosylation is required for the Abs production and plays a vital role in prevention of S.typhimurium infection.Loss of Core fucosylation suppressed the sIgA production specific for S.typhimurium,which resulted in susceptibility of mice to this pathogen.In this scenario,Core fucosylation plays important roles in host defense against S.typhimurium infection.With a better understanding of how Core fucosylation regulates of the humoral immune response,we could control the S.typhimurium infection with new intervention from glycosylation's perspective.