B细胞内源性拟素化可调控小鼠免疫反应OA

Objective:To investigate the regulatory role of endogenous neddylation in B cell-mediated immune responses.Methods:B cell-specific Ube2m knockout mice(CD19cre/+Ube2mfl/fl)were generated using the Cre-LoxP system,with littermate Ube2mfl/fl mice serving as normal controls.Mice were immunized with thymus-independent antigens 4-hydroxy-3-nitrophenylacetyl(NP)-lipopoly saccharide(LPS)and 2,4-dinitrophenyl(DNP)-Ficoll,as well as thymus-dependent antigens NP-chicken gamma globulin(CGG)and DNP-keyhole limpet hemocyanin(KLH).Serum levels of specific antibodies were measured by enzyme-linked immunosorbent assay(ELISA).Flow cytometry was used to determine the proportions of splenic germinal center B cells,splenic plasma cells,and bone marrow plasma cells in mice immunized with NP-LPS or NP-CGG.Statistical analyses were performed to assess differences in immune responses among the groups.Results:Compared with controls,Ube2m-deficient mice showed significantly lower levels of anti-NP immunoglobulin(Ig)G2a,IgG2b,IgG2c,and IgG3 after NP-LPS immunization,and reduced levels of all anti-DNP IgG subclasses after DNP-Ficoll immunization(all P<0.05),with no significant change in IgM levels.The proportions of total splenic germinal center B cells,total bone marrow plasma cells,and NP-specific plasma cells were also significantly decreased after NP-LPS immunization(all P<0.01).Following immunization with NP-CGG or DNP-KLH,Ube2m knockout mice exhibited reduced levels of anti-NP or anti-DNP IgM and all IgG subclasses(all P<0.05),with antigen-dependent differences in the timing and extent of antibody reduction.After NP-CGG immunization,the proportions of total splenic plasma cells,NP-specific plasma cells,and NP-specific germinal center B cells were markedly decreased(all P<0.01).Conclusion:Endogenous neddylation deficiency in B cells broadly impairs immune responses to both thymus-independent and thymus-dependent antigens in mice,and its regulatory effects are antigen-dependent.