Changes in expression of monoclonal antibody epitopes on laminin-5r induced by cell contact.
Laminin-5r is a basement membrane component that promotes rapid adhesion and hemidesmosome formation in epithelial cells. We raised monoclonal antibodies and identified their corresponding epitopes on the constituent chains of laminin-5r by western blotting. Using a combination of immunoprecipitation and ELISA assays, we determined that these epitopes are differentially exposed on two forms of the laminin-5r heterotrimer: soluble (passively adsorbed onto plastic) and cell-associated. Antibody 5C5 epitope is exposed on the cell-associated form, but not the soluble/passively adsorbed form of laminin-5r. Epitopes reactive with antibodies CM6, FM3, and TR1 are also preferentially exposed on cell-associated laminin-5r, such that reactivity of these antibodies with the cell-associated form is fourfold higher than with the soluble/passively adsorbed form in ELISA assays. Incubation of passively adsorbed laminin-5r with the human epithelial cell line SCC12 induced exposure of 5C5 and CM6, FM3, or TR1 epitopes. These data suggest that cells actively modify laminin-5r, perhaps during matrix assembly, and that the 5C5 epitope may serve as a marker for assembled laminin-5r matrix.
Plopper
G
G
Department of Cell Biology/SBR 12, Scripps Research Institute, La Jolla, CA 92037, USA.
Falk-Marzillier
J
J
Glaser
S
S
Fitchmun
M
M
Giannelli
G
G
Romano
T
T
Jones
J C
JC
Quaranta
V
V
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000276:immunology*; D002450:Cell Communication; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D051381:Rats; D014407:Tumor Cells, Cultured; D000097794:Kalinin
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D000939:Epitopes; D000097794:Kalinin