Immunogenic and Antigenic Epitopes of Immunoglobulins X: Monoclonal Antibodies Specific for Human IgA, the IgA1 and IgA2 Subclasses and an nA2m(2) Iso‐Allotypic Epitope

Abstract

Monoclonal antibodies (McAb) specific for human IgA, the IgA1 and IgA2 subclasses and the iso-allotypic epitope nA2m(2) have been produced. Three distinct McAb recognise an IgA1-specific epitope expressed in the Cα2 domain or the hinge region whilst a further McAb is directed possibly to an IgA1 hinge region epitope. The McAb having nA2m(2) specificity recognises an iso-allotypic epitope expressed within the Fab region. IgA1 and IgA2 epitopes were detected in gorilla but not rhesus or baboon sera suggetting that the IgA subclasses represent a recent gene duplication event. However, these epitopes were also detected in some non-primate sera.