Localization of a tumor cell adhesion domain of laminin by a monoclonal antibody.
Monoclonal antibodies were prepared to localize the domain(s) of laminin to which tumor cells adhere. Rat Y3-Ag 1.2.3 myeloma cells were fused with spleen cells from a rat immunized with a purified 440-kDa fragment of chymotrypsin-digested laminin. Three monoclonal antibodies (AL-1 to AL-3) that bound to intact laminin in a solid-phase radioimmunoassay were chosen for further analysis. The epitopes recognized by these antibodies were characterized by radioimmunoassays, immunoblotting, radioimmunoprecipitation, and immunoaffinity chromatography. In cell adhesion assays, monoclonal antibody AL-2 inhibited the binding of the highly metastatic melanoma cell line, K-1735-M4, to both intact laminin and the 440-kDa fragment of laminin. Electron microscopic examination of laminin-monoclonal antibody interactions showed that monoclonal antibody AL-2 reacted with the long arm of laminin directly below the cross-region. Two monoclonal antibodies that failed to inhibit tumor cell adhesion to laminin reacted with epitopes on the lateral short arms or cross-region of laminin as seen by electron microscopy. These results suggest that a new tumor cell binding domain of laminin may be located close to the cross-region on the long arm of laminin.
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455.
A P
AP
Skubitz
A S
AS
Charonis
E C
EC
Tsilibary
L T
LT
Furcht
D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D001666:Binding Sites, Antibody; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002918:Chymotrypsin; D007118:Immunoassay; D007797:Laminin / Q000276:immunology / Q000302:isolation & purification* / Q000502:physiology; D008297:Male; D008546:Melanoma, Experimental / Q000032:analysis / Q000648:ultrastructure; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D014407:Tumor Cells, Cultured / Q000032:analysis* / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D007797:Laminin; D002918:Chymotrypsin