The nature of neutralization reaction between effector protein and monoclonal antibody: a quantitative study of neutralization characteristics of anti-interferon antibodies.

Several monoclonal antibodies to human interferon-alpha and beta were examined quantitatively for neutralization of antigenically homogeneous interferons. The extent of neutralization increased with antibody concentration in each case with a rate considerably lower than in the case of conventional (polyclonal) antibodies, and there often appeared to be a limit to the maximum interferon titre that can be neutralized, even using very high antibody concentrations (there were no such limits with conventional antibodies). This suggests that the interferon in a 1:1 interferon-antibody complex in general retains some activity, to the degree characteristic of that antibody; namely, each monoclonal antibody is considered to have a characteristic efficacy of neutralization, rather than being either neutralizing or non-neutralizing in an all-or-one fashion. The antibody dose-dependence curves were interpreted to be governed by two independent parameters of the antibody: the efficacy of neutralization and the affinity. The former is reflected by the maximum interferon titre neutralizable by high antibody doses and the latter by the minimum antibody dose that can effect detectable neutralization. Thus, quantitative neutralization tests of monoclonal antibodies to an effector protein would give useful information for classifying them as to their affinities and as to whether the epitopes they recognize are important for the biological activity of the effector.