Serological and Immunofluorescent Study of Soluble Collagen in Tissue Culture of Fibroblasts

SummaryTo localize the synthesis of collagen precursor within fibroblasts, antibodies against purified neutral salt-soluble collagen fraction of chicken leg tendon were induced in adult rabbits. The antibodies against this presumed precursor of insoluble mature collagen had, (a) a high titer against specific antigen on complement fixation (1:1600), and on hemagglutination (1:15,000); (b) a single precipitin band in agar double diffusion and in immunoelectrophoresis; and (c) high specificity as to species and collagen fraction in cross reactions with citrate-soluble and insoluble collagen of chicken tendon, with neutral salt-soluble collagen of bovine sclera, and with an acetic extract of ichthyocol. Neutral salt-soluble collagen was localized by immunofluorescence in the cytoplasm, and processes of mature cultured fibroblasts, but not in undifferentiated cells.