CELL-BINDING PROPERTIES OF COLLAGEN TYPE-XIV FOR HUMAN HEMATOPOIETIC-CELLS

Collagen XIV, which belongs to the subclass of fibril-associated colla gens with interrupted triple helices (FACITs), is a homotrimeric molec ule consisting of three ctl (XIV) chains. Collagen type XIV is strongl y expressed in the native human bone marrow, as shown by immunofluores cence staining and immunoblotting with an affinity-purified antibody. Hematopoietic cell lines of myeloid (KG1a, U937, K562) and lymphoid (U 266, IM-9) origin were able to attach firmly to purified human collage n XIV preparations. Attachment of these cells was shown to be concentr ation-dependent. However, other hematopoietic cell lines tested were u nable to adhere to collagen XIV, indicating restriction of this cellul ar interaction. The cellular receptors involved in cell binding to col lagen type XIV are probably membrane-bound heparansulfate proteoglycan s, since only the the addition of heparin inhibited attachment of the hematopoietic cells to collagen XIV in a concentration-dependent manne r. Antibodies against the beta 1-integrin subunit could not interfere with binding to collagen type XIV. Using purified fragments of collage n XIV, it could be demonstrated that at least two different heparin-se nsitive adhesion sites are present in the N-terminal globular domain a nd in the triple-helical domain. These data indicate that collagen XIV represents another collagen type expressed in human bone marrow with strong cell binding properties for defined populations of hematopoieti c cells.