Ly49Q ligand expressed by activated B cells induces plasmacytoid DC maturation.
Ly49Q, a type II C-type lectin expressed on mouse plasmacytoid DC (pDC), contains a single carbohydrate recognition domain in its extracellular region and an ITIM in its cytoplasmic domain. We have identified the MHC class I molecule H-2K(b) as a Ly49Q ligand, confirming prior reports. Although H-2K(b) is expressed on essentially all hematopoietic cells, we found that only CpG-stimulated B cells were able to activate Ly49Q. This discovery correlated with our finding that although H-2K(b) forms clusters on CpG-activated B cells, it is diffusely expressed on resting B cells. Furthermore, CpG-stimulated, but not resting, B cells up-regulated co-stimulatory molecules on pDC. This finding was confirmed by the fact that binding by anti-Ly49Q mAb to Ly49Q led to pDC maturation in vitro. Our results suggest that clustered H-2K(b) on activated B cells act as ligands for Ly49Q and induce pDC maturation in vitro.
Department of Otolaryngology - Head and Neck Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Makiko
M
Toma-Hirano
Sahori
S
Namiki
Yasue
Y
Shibata
Koji
K
Ishida
Hisashi
H
Arase
Shoichiro
S
Miyatake
Ken-ichi
K
Arai
Yumiko
Y
Kamogawa-Schifter
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D018899:CpG Islands / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006183:H-2 Antigens / Q000276:immunology; D007113:Immunity, Innate / Q000276:immunology; D007150:Immunohistochemistry; D037181:Lectins, C-Type / Q000276:immunology*; D008024:Ligands; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055650:NK Cell Lectin-Like Receptor Subfamily A / Q000276:immunology*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000276:immunology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000276:immunology; D013047:Specific Pathogen-Free Organisms
D016207:Cytokines; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D037181:Lectins, C-Type; D008024:Ligands; D055650:NK Cell Lectin-Like Receptor Subfamily A; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509248:Ptpn6 protein, mouse