[Production and characterization of monoclonal antibodies to the secretory components of human IgA].

The monoclonal antibodies BL-HSC/1-3 are characterized by means of indirect radioimmunotechnique with regard to their binding pattern to a set of human proteins. The results suggest a binding specificity of the three monoclonals for A-determinants of the human secretory component. However, we could not point out a different binding pattern to the immunoglobulin-bound and the free molecule, respectively. By use of appropriate immunoassays, the monoclonal antibody BL-HSC/3 is the most suitable one for the detection of the secretory component and secretory IgA in body fluids. The protein band labeled by BL-HSC/3 in the immunoblotting analysis corresponds to a molar mass of 79,000 D according to the data known for the human secretory component.