Binding of hyaluronic acid to lymphoid cell lines is inhibited by monoclonal antibodies against Pgp-1.
Recent biochemical and sequence data suggest a possible relationship between Pgp-1 (identical to CD44/Hermes 1/p85) and a hyaluronic acid-binding function. Here, we have studied the hyaluronic acid-binding activity of a series of murine hematopoietic cell lines using several assays: cell aggregation by hyaluronic acid, binding of fluorescein-conjugated hyaluronic acid, and cell adhesion to hyaluronic acid-coated dishes. Certain Pgp-1-positive T and B cell lines show hyaluronic acid binding that is highly specific and is not competed for by other glycosaminoglycans. Monoclonal antibodies against Pgp-1, but not antibodies against other major cell surface glycoproteins, inhibited hyaluronic acid-induced cell aggregation and cell adhesion to hyaluronic acid-coated dishes. Additionally, some anti-Pgp-1 antibodies inhibited binding of fluorescein-hyaluronic acid to hyaluronic acid-binding lines. We found no Pgp-1-negative lines that bound, but many Pgp-1-positive cell lines did not bind hyaluronic acid. Two Pgp-1-positive thymomas that did not bind hyaluronic acid were induced by phorbol ester to bind hyaluronic acid with the same specificity as other hyaluronic acid-binding lines. Normal hematopoietic cells, including those which express high levels of Pgp-1, such as bone marrow myeloid cells and splenic lymphocytes, showed no detectable hyaluronic acid-binding activity. We discuss several models that might account for these observations: (1) the hyaluronic acid receptor is Pgp-1, but it normally exists in an inactive state; (2) hyaluronic acid receptors are a subset of a family of molecules recognized by anti-Pgp-1 antibodies; (3) the hyaluronic acid receptor is not Pgp-1, but is closely associated with Pgp-1 on the surface of cells which express hyaluronic acid-binding activity.
Lesley
J
J
Salk Institute, San Diego, California 92138.
Schulte
R
R
Hyman
R
R
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000943:Antigens, Differentiation / Q000276:immunology*; D001402:B-Lymphocytes; D015815:Cell Adhesion Molecules / Q000276:immunology* / Q000378:metabolism; D002449:Cell Aggregation / Q000187:drug effects; D002460:Cell Line; D006820:Hyaluronic Acid / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D016201:Receptors, Lymphocyte Homing; D013601:T-Lymphocytes; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D015815:Cell Adhesion Molecules; D016201:Receptors, Lymphocyte Homing; D006820:Hyaluronic Acid