Chinese hamster lung cells synthesize and confine to the cellular domain a collagen composed solely of B chains.

The acid-soluble collagen extracted from cultured Chinese hamster lung (CHL) cell layers has been isolated after limited pepsin digestion and differential salt fractionation. Polyacrylamide gel electrophoresis of this material under denaturing conditions showed the presence of collagen chains with an apparent molecular mass of 120,000 daltons both before and after reduction, indicating the absence of interchain disulfide bonds in the native molecule. When chromatographed on CM-cellulose under denaturing conditions, the majority (> 90%) of the CHL cell layer collagen chains eluted as relatively basic components slightly before the human alpha 2(I) chain and coincident with the human B chain. In addition, the CM-cellulose elution profiles of the cyanogen bromide peptides derived from the human B chain and from the CHL cell layer chain were essentially identical. Examination of CHL cells in culture by using affinity-purified antibody to human B chain revealed this collagen to be localized in an extracellular matrix surrounding the cells. Furthermore, analysis of the culture medium indicated the absence of any comparable collagen chain. These data provide additional evidence for the existence of a molecular form of collagen composed solely of B chains and suggest that this molecular form of collagen has an unusual affinity for the cell layer in this system.