Biosynthesis of IgG in periapical lesion explant cultures

The presence of immunoglobulins has been demonstrated in periapical inflammatory lesions associated with endodontic disease. The purpose of this study was to determine if IgG is synthesized in vitro in explant cultures of untreated periapical inflammatory lesions and to determine the level of IgG in isolated samples. Periapical lesions associated with infected root canals were removed from the roots and cultured in tissue culture medium containing tritiated amino acids. Supernatant fluids from the explant tissue cultures were passed through staphylococcal protein A affinity columns to isolate IgG. When the staphylococcal protein A eluents (24-h samples) from six periapical lesions were used in double diffusion in agarose assays, the presence of IgG was demonstrated in all the samples. Radial immunodiffusion assays to quantitate the IgG in staphylococcal protein A eluents showed that the levels of IgG detected in each successive daily supernatant fluid always decreased or else fell below the lower limits of detection. The in vitro biosynthesis of IgG in explant cultures of periapical lesions was demonstrated by the incorporation of tritiated amino acids into isolated IgG.