B cell activation regulates exosomal HLA production.
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 contact with CD4(+) T cells. Neutralizing anti-CD154 (CD40L) mAb inhibited this effect, and a soluble CD40L 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-kappaB pathway drastically inhibited exosomal HLA production in stimulated B cells, indicating that the classical NF-kappaB pathway is critical for exosomal HLA production in B cells. Together, these findings suggest a pivotal role of B cell activation in exosomal HLA production in vivo.
Arita
Shuji
S
Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
Baba
Eishi
E
Shibata
Yoshihiro
Y
Niiro
Hiroaki
H
Shimoda
Shinji
S
Isobe
Taichi
T
Kusaba
Hitoshi
H
Nakano
Shuji
S
Harada
Mine
M
D000730:Androstadienes / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D001402:B-Lymphocytes / Q000187:drug effects / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D023201:CD40 Ligand / Q000037:antagonists & inhibitors / Q000276:immunology / Q000494:pharmacology; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000737:chemistry; D022162:Cytoplasmic Vesicles / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D006680:HLA Antigens / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D006684:HLA-DR Antigens / Q000097:blood / Q000276:immunology / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000097:blood / Q000276:immunology / Q000378:metabolism; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008213:Lymphocyte Activation / Q000502:physiology*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000819:agonists / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051217:Toll-Like Receptor 9 / Q000819:agonists / Q000502:physiology; D000077191:Wortmannin
D000730:Androstadienes; D000911:Antibodies, Monoclonal; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D006680:HLA Antigens; D006684:HLA-DR Antigens; D015395:Histocompatibility Antigens Class I; C508598:IL4 protein, human; D007476:Ionophores; D016328:NF-kappa B; D011947:Receptors, Antigen, B-Cell; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D023201:CD40 Ligand; D015847:Interleukin-4; D000077191:Wortmannin