B cell activation regulates exosomal HLA production

Shuji Arita, Eishi Baba, Yoshihiro Shibata, Hiroaki Niiro, Shinji Shimoda, Taichi Isobe, Hitoshi Kusaba, Shuji Nakano, Mine Harada

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


Exosomes are nanovesicles produced constitutively and inducibly by several types of cells. They are generated as intraluminal vesicles of multivesicular bodies and express MHC and several endosomal/lysosomal proteins. In spite of their potential role in cellular immunity, the regulatory mechanisms of exosome production are largely unknown. in this study, we have established a novel ELISA system to quantify exosomal HLA using a combination of anti-HLA class I and anti-HLA-DR mAb. We found that exosomal HLA production of B cells was enhanced by contactwith CD4+T cells. Neutralizing anti-CD154 (CD40L) mAb inhibited this effect, and a soluble CD40I. significantly increased production of exosomal HLA in B cells. In addition, B cell stimulation via BCR and TLR9 enhanced their production while IL-4 stimulation alone failed to do so. Strikingly, an inhibitor of the classical NF-κB pathway drastically inhibited exosomal HLA production in stimulated B cells, indicating that the classical NF-κB pathway is criticol for exosomal HLA production in B cells. Together, these findings suggest a pivotal role of B cell activation in exosomal HLA production in vivo.

Original languageEnglish
Pages (from-to)1423-1434
Number of pages12
JournalEuropean Journal of Immunology
Issue number5
Publication statusPublished - May 2008

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


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