Monoclonal Antibodies Against Gingival Components

¹ Department of Oral Pathology, Osaka Dental University, 1-47, Kyobashi, Higashi-Ku, Osaka 540, Japan

The aim of this study was to produce and characterize monoclonal antibodies against human gingival epithelial cells and gingival fibroblasts. By using these whole cells as immunogens, we were able to generate a large number of monoclonal antibodies reacting with tissue antigens, in particular antibodies that reacted with desmosomes (MoAbs 7 and 8) and basement membrane (MoAb FB-1) antigens. MoAbs 7 and 8 produced from epithelial cells stained cell membranes of epithelium and desmosomes, respectively, as shown by light and immunoelectron microscopy. The epitopes to which MoAbs 7 and 8 were reactive were stable against various treatments; only periodate oxidation abolished the tissue reactions with MoAb 8. Extraction of gingiva with SDS or NP-40, SDS-PAGE analysis, and Western blotting showed that the MoAb 8 identified an antigen with a molecular weight of 100,000 daltons. MoAb FB-1 produced from fibroblasts immunolabeled the basement membranes. The FB-1 antigen was clearly different from any of the known ubiquitous basement membrane components, such as type IV collagen, laminin, and fibronectin. Examination of the distribution and localization of the antigen showed that it was present in the basement membrane beneath stratified squamous epithelium. FB-1 did not react with any of types I-VI collagens in ELISA, but immunoelectron microscopy showed that the antigen reacting with FB-1 was present in the lamina fibroreticularis of the basement membrane and was comprised of collagen-like fibers. These results suggest the possible existence of a new collagen other than types I-VI in the basement membrane beneath stratified squamous epithelium.