生发中心
CD1D公司
CD40
生物
MHC II级
免疫学
免疫系统
B细胞
自然杀伤性T细胞
细胞生物学
CD1型
T细胞
MHC I级
获得性免疫系统
T辅助细胞
细胞毒性T细胞
主要组织相容性复合体
抗体
体外
遗传学
作者
Elena Tonti,Maya Fedeli,Anna Napolitano,Matteo Iannacone,Ulrich H. von Andrian,Luca G. Guidotti,Sergio Abrignani,Giulia Casorati,Paolo Dellabona
出处
期刊:Journal of Immunology
[The American Association of Immunologists]
日期:2012-04-01
卷期号:188 (7): 3217-3222
被引量:93
标识
DOI:10.4049/jimmunol.1103501
摘要
B cells require MHC class II (MHC II)-restricted cognate help and CD40 engagement by CD4(+) T follicular helper (T(FH)) cells to form germinal centers and long-lasting Ab responses. Invariant NKT (iNKT) cells are innate-like lymphocytes that jumpstart the adaptive immune response when activated by the CD1d-restricted lipid α-galactosylceramide (αGalCer). We previously observed that immunization of mice lacking CD4(+) T cells (MHC II(-/-)) elicits specific IgG responses only when protein Ags are mixed with αGalCer. In this study, we investigated the mechanisms underpinning this observation. We find that induction of Ag-specific Ab responses in MHC II(-/-) mice upon immunization with protein Ags mixed with αGalCer requires CD1d expression and CD40 engagement on B cells, suggesting that iNKT cells provide CD1d-restricted cognate help for B cells. Remarkably, splenic iNKT cells from immunized MHC II(-/-) mice display a typical CXCR5(hi)programmed death-1(hi)ICOS(hi)Bcl-6(hi) T(FH) phenotype and induce germinal centers. The specific IgG response induced in MHC II(-/-) mice has shorter duration than that developing in CD4-competent animals, suggesting that iNKT(FH) cells preferentially induce transient rather than long-lived Ab responses. Together, these results suggest that iNKT cells can be co-opted into the follicular helper function, yet iNKT(FH) and CD4(+) T(FH) cells display distinct helper features, consistent with the notion that these two cell subsets play nonredundant functions throughout immune responses.
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