Replica analysis of the class of antibodies produced by single cells

Abstract

Improvements have been made in a localized haemolysis in gel replica assay developed previously. The technique is designed to show if an individual antibody producing cell releases antibody of one or more classes. The techniques can also be used to indicate the specificity of antibodies produced by individual cells by using two different antigens in the test system. In experiments where both slides of a slide-pair are untreated or treated identically, and 100% coincidence of plaques is expected, the technique has been shown to detect about 95% coincidence. Pairs of slides treated differently to reveal plaques due to antibodies of different classes show a mean of about 3·5% coincident plaques. This `background' of coincidence which it is thought is not due to `double-producers', is one of the limiting factors of the technique.