Complement Cls, a classical enzyme with novel functions at the endochondral ossification center: Immunohistochemical staining of activated Cls with a neoantigen-specific antibody

Hisako Sakiyama, Koichi Nakagawa, Kazuko Kuriiwa, Kazushi Imai, Yasunori Okada, Toyomitsu Tsuchida, Hideshige Moriya, Shinobu Imajoh-Ohmi

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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.

Original languageEnglish
Pages (from-to)557-565
Number of pages9
JournalCell and Tissue Research
Issue number3
Publication statusPublished - 1997 Jun 24



  • Cartilage
  • Complement Cls
  • Decorin
  • Human
  • Hypertrophic chondrocyte
  • Immunohistochemistry
  • Neoantigen
  • Rheumatoid arthritis
  • Syrian hamster

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology

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