An investigation into the possible effects of proteolysis on IgM enzyme-linked immunosorbent assay titres

On the basis of the theory of affinity it is shown that enzyme-linked immunosorbent assay titres cannot increase as a result of proteolysis when all the antibody proteolytic fragments have approximately the same association constants as the intact antibody for the reaction with the antigen and with the enzyme-conjugated antibody. This finding was experimentally confirmed by proteolysis experiments carried out with a monoclonal IgM antibody against Lewis^b antigen using trypsin. The experimental results with this particular antibody confirmed that proteolysis cannot enhance ELISA titres in hybridoma cultures with serum-free medium or with serum-supplemented medium.