ヒトろ胞樹状細胞（ｆｏｌｌｉｃｕｌａｒ ｄｅｎｄｒｉｔｉｃ ｃｅｌｌ： ＦＤＣ）における接着分子の発現 特にｆｉｂｒｏｎｅｃｔｉｎ‐およびｌａｍｉｎｉｎ‐ｒｅｃｅｐｔｏｒについて

Abstract

The expression of adhesion molecules on human tonsillar follicular dendritic cells (FDCs) in vivo on cryostat sections and in vitro on isolated FDCs on cytospin preparations was studied. Isolation of FDCs was performed using a magnetic cell sorter (MACS). Immunochemically, FDCs were positive for Mac-1 (CD11b), sialyl-Lex (CD15s), CD22, integrin β1 (CD29), CD40, VLA-α3 (CD49c), VLA-α5 (CD49e), VLA-α6 (CD49f), ICAM-3 (CD50), ICAM-1 (CD54), B7 (CD80), and VCAM-1 (CD106). These adhesion molecules, except ICAM-3 (CD50) which was weakly positive only in the light zone (LZ), were positive with a lacy pattern in all zones of secondary lymphoid follicle, especially strong in the LZ. ICAM-3 (CD50) was positive on more than half of isolated FDCs, but other molecules were positive on almost all isolated FDCs. Concerning the ligands on B cells for these adhesion molecules, the Mac-1 (CD11b)-ICAM-1 (CD54), the ICAM-3 (CD50)-LFA-1 (CD11a/18), and the VCAM-1 (CD106)-VLA-4 (CD29/49d) interactions in the LZ, the sialy-Lex (CD15s)-L-selectin (CD62L) and the VCAM-1 (CD106)-VLA-4 (CD29/49d) interactions in the mantle zone, and the ICAM-1 (CD54)-LFA-1 (CD11a/18) interaction in the entire lymphoid follicle may participate in FDC-B cell adhesion. Furthermore, above mentioned immunohistochemical evidence that FDCs were positive for fibronectin-receptor (CD29/CD49e) and laminin-receptor (CD29/CD49f), was confirmed with a frozen-section binding assay, using isolated FDCs and cryostat sections of tonsils. The numbers of FDCs binding to germinal centers (GCs) were reduced remarkably by pretreatment with monoclonal antibodies for CD29 (32.8±4.1% of the control), CD49e (29.7±2.5%), and CD49f (18.8±0.8%). These data clearly indicated that FDCs bind to the reticulin or laminin fiber in GCs via either receptor.