Evidence is presented that monoreactive antibodies exposed to low pH may acquire the ability to bind to multiple antigens. M11, a murine, monoclonal, IgM(K) anti-goat IgG (GIgG) was purified from a hybridoma supernatant by elution at low pH from an anti-mu-Sepharose 4B affinity column. By measuring the specific antiGIgG activities and the affinity constants for the interactions of M11, pre- and post-affinity-purification, with GIgG, M11 was shown to be monoreactive before purification. Quite unexpectedly, however, the affinity-purified M11 reacted extensively with size-fractionated liver proteins when tested in an immunoblot, clearly indicating that it was polyreactive. It was concluded that the exposure to low pH had altered the M11 binding-site so as to allow it to bind to many different proteins. This phenomena provides an alternative basis for interpreting the polyreactivity observed following affinity-purification.
McMahon, M. J., & O'Kennedy, R. (2000). Polyreactivity as an acquired artefact, rather than a physiologic property, of antibodies: evidence that monoreactive antibodies may gain the ability to bind to multiple antigens after exposure to low pH. Journal of immunological methods, 241(1-2), 1-10. https://doi.org/10.1016/S0022-1759(00)00196-4