The hematopoietic and epithelial forms of CD44 are distinct polypeptides with different adhesion potentials for hyaluronate-bearing cells.

Abstract

CD44 is a polymorphic integral membrane protein which recognizes hyaluronate and whose proposed roles encompass lymphocyte activation, matrix adhesion and the attachment of lymphocytes to lymph node high endothelial venules (HEVs). Immunochemical and RNA blot data have supported the existence of two forms of CD44: a hematopoietic form expressed by cells of mesodermal origin (and by some carcinoma cell lines) and an epithelial form weakly expressed by normal epithelium but highly expressed by carcinomas. This report describes the isolation of a cDNA encoding a distinct CD44 polypeptide expressed by epithelial cells. Re‐expression of each form of CD44 in a B cell line allowed cells transfected with the hematopoietic but not the epithelial form to bind to viable rat lymph node HEV cells in primary culture.

Hyaluronan: fundamental principles and applications in cancer

“…It mediates the HYA-binding of human myeloid KG1 and KG1 A cells [26]. CD44 seems to have different affinities for HYA according to its origin [27,28] and in some cases, CD44 can be expressed without HYA-binding activity [29]. CD44 was identified with HYA-binding activity in the SV-3T3 fibroblasts already mentioned, and subsequently in many other kind of cell.…”

“…As noted above, this binding site was later defined as CD44, which is responsible for the adhesion of HYA to endothelial cells [22] and human myeloid cell lines [26], and for the adhesion of B-lineage lymphocytes to stroma cells [25]. CD44 can be distinguished in two forms, one epithelial and the other haemopoietic, with different adhesion potentials for HYA-bearing cells [27,28]. There is not a simple equivalence between the ability to bind HYA and the expression of CD44 [24,29].…”

The study of hyaluronic acid compounds for neutron capture and photon activation therapies

“…HA has physicochemical and biological properties that hatdetermine the biocompatibility, biodegradation without reactive toxic product formation. Also HA has attracted much attention in tumor-targeted delivery because of its ability to specifically bind to various cancer cells that overexpress CD44 receptor [14]. Therefore, the synthesis of compounds on the basis of HA is a prospective direction to search for compounds for NCT and PAT.…”

Increase in the expression of the transmembrane surface receptor CD44v6 on chondrocytes in animals with osteoarthritis

“…CD44 is broadly distributed, and it occurs in a standard isoform and in several isoforms (9) as alternatively spliced variant exonencoded gene products (10). Its isoform diversity is determined by variable exon usage, glycosaminoglycan substitution, and cell type-specific N-and O-linked glycosylation (11). CD44H, with a molecular mass of 90 kd, is the standard isoform that lacks the variable exons 6-15.…”

“…CD44H, with a molecular mass of 90 kd, is the standard isoform that lacks the variable exons 6-15. The standard isoform is the most broadly expressed (2,4,11). The alternatively spliced isoforms are CD44v1-10.…”