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AN ANTIGEN OF CHONDROITIN SULFATE PROTEOGLYCAN; A MARKER FOR CARTILAGE DIFFERENTIATION
Author(s) -
CRAWFORD TERRY
Publication year - 1980
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1980.00113.x
Subject(s) - cartilage , antigen , ouchterlony double immunodiffusion , aggrecan , chemistry , microbiology and biotechnology , proteoglycan , chondroitin sulfate , in vitro , biology , antiserum , immunology , biochemistry , glycosaminoglycan , pathology , osteoarthritis , anatomy , medicine , alternative medicine , articular cartilage
Antisera to the chondroitin sulfate proteoglycan complex (CPG) of cartilage were used to study the specificity of the CPG‐associated antigen as a biochemical marker for cartilage differentiation and to study the expression of differentiation by cultured chondrocytes. Of 7 tissues tested, antigen giving an identity reaction with this protein could be detected by the Ouchterlony double diffusion test in extracts of sternum and brain of 14‐day chick embryos. Extracts of 2 non‐cartilage tissues gave a reaction indicating that they contain a related, but not identical antigen. Ouchterlony double diffusion tests showed that extracts of morphologically differentiated chondrocytes cultured in vitro contain the CPG‐associated antigen. The radio‐precipitin test, used to quantitate the rate of synthesis of this antigen, provided a measure of cartilage phenotype expression in culture. The cultured chondrocytes synthesized antigenic protein at a rate similar to that of 14‐day sternum. In contrast to intact cartilage, however, the cultured chondrocytes released much of the newly synthesized antigen into the medium. The possibility was explored that synthesis of the CPG‐associated antigen might be characteristic of all cells in culture, and not a specific expression of the cartilage phenotype. However, skin fibroblast cultures only contained detectable antigen of the “partially identical” type.