title: Complement Cls, a classical enzyme with novel functions at the endochondral ossification center: immunohistochemical staining of activated Cls with a neoantigen-specific antibody.
abstract: The secondary ossification center of 14- to 16-day-old hamster tibiae was examined immunohistochemically with active and inactive Cls-specific antibodies, RK5 and RK4, respectively. At the ossification center, chondrocytes differentiate from proliferating and hypertrophic to degenerating stages, and their site is occupied by the bone marrow. Cls was strongly immunostained in hypertrophic chondrocytes. In order to discover whether Cls is activated at a particular site, the cartilage was immunostained with RK5 and RK4. RK5 mainly reacted with degrading matrix around invading vessels. In contrast, RK4 strongly stained hypertrophic chondrocytes. Immunoelectron microscopy revealed Cls on degrading fragments of chondrocytes and fibers of cartilage matrix. Decorin, one of the major matrix proteoglycans, was dose and time dependently degraded by Cls. Type II collagen and type I gelatin were also degraded. Articular cartilage from patients with rheumatoid arthritis was positively immunostained (11/12 cases) with an anti-Cls monoclonal antibody (mAb) PG11, whereas normal articular cartilage (5/5 cases) was negative, suggesting Cls participation in the etiology of rheumatoid arthritis.
authors.affiliation: Division of Biology and Oncology, National Institute of Radiological Sciences, 4-9-1, Anagawa Inage-ku, Chiba 263, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sakiyama
authors.forename: K
authors.initials: K
authors.lastname: Nakagawa
authors.forename: K
authors.initials: K
authors.lastname: Kuriiwa
authors.forename: K
authors.initials: K
authors.lastname: Imai
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: T
authors.initials: T
authors.lastname: Tsuchida
authors.forename: H
authors.initials: H
authors.lastname: Moriya
authors.forename: S
authors.initials: S
authors.lastname: Imajoh-Ohmi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology / Q000503:physiopathology*; D002454:Cell Differentiation; D003094:Collagen / Q000378:metabolism; D003173:Complement C1s / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D006224:Cricetinae; D058575:Decorin; D016326:Extracellular Matrix Proteins; D005780:Gelatin / Q000378:metabolism; D006132:Growth Plate / Q000166:cytology / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D007719:Knee Joint; D008647:Mesocricetus; D008969:Molecular Sequence Data; D010012:Osteogenesis; D010446:Peptide Fragments / Q000737:chemistry; D011509:Proteoglycans / Q000032:analysis / Q000378:metabolism; D013977:Tibia
chemical_list: C546878:DCN protein, human; D058575:Decorin; D016326:Extracellular Matrix Proteins; D010446:Peptide Fragments; D011509:Proteoglycans; D005780:Gelatin; D003094:Collagen; D003173:Complement C1s