Invariant NKT cells sustain specific B cell responses and memory

Grazia Galli, Paola Pittoni, Elena Tonti, Carmine Malzone, Yasushi Uematsu, Marco Tortoli, Domenico Maione, Gianfranco Volpini, Oretta Finco, Sandra Nuti, Simona Tavarini, Paolo Dellabona, Rino Rappuoli, Giulia Casorati, Sergio Abrignani

Research output: Contribution to journalArticlepeer-review


Invariant natural killer T (iNKT) cells are innate-like lymphocytes recognizing CD1d-restricted glycolipid antigens, such as α- galactosylceramide (αGC). We assessed whether iNKT cells help B lymphocyte responses and found that mice immunized with proteins and αGC develop antibody titers 1-2 logs higher than those induced by proteins alone. Activation of iNKT cells enhances protection against infections such as influenza and elicits higher frequencies of memory B cells and higher antibody responses to booster immunizations. Protein vaccination with αGC, but not with conventional adjuvants, elicits IgG responses in mice lacking MHC class II molecules, demonstrating that iNKT cells can substitute for CD4+ T cell help to B cells. Interestingly, the decay of circulating antibodies is faster in mice lacking iNKT cells. These findings point to a homeostatic role for iNKT cells on critical features of the antibody response such as immunity and B cell memory.

Original languageEnglish
Pages (from-to)3984-3989
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number10
Publication statusPublished - Mar 6 2007


  • α-galactosylceramide
  • B cell memory
  • Protein vaccination
  • Serological memory

ASJC Scopus subject areas

  • Genetics
  • General


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