Detection of antibody to hepatitis B core antigen (anti-HBc) using a direct (antiglobulin) format and development of a confirmatory assay for anti-HBc.

A direct (antiglobulin) solid-phase enzyme immunoassay for the detection of antibody to hepatitis B core antigen (anti-HBc) is described. The assay utilizes recombinant hepatitis B core antigen as the solid-phase 'capture' reagent and a mixture of monoclonal antibodies specific for human IgG and IgM conjugated to horseradish peroxidase as the 'detector' reagent. The direct assay demonstrated excellent sensitivity and specificity when compared with a commercially available competitive enzyme immunoassay.

Enhanced binding activity observed between anti-carcinoembryonic monoclonal antibodies.

Six anti-carcinoembryonic monoclonal antibodies (CEA MAbs) were isolated and characterized. Through blocking studies, only two were found to share the same epitope, indicating that CEA has at least five different epitopic sites. One of the group, 31C5A4 was found to enhance greatly the binding of CEA by 20C2H1.

The detection of circulating immune complexes containing C1q and IgG using a new rapid serum ELISA test system.

An ELISA sandwich assay for detecting circulating immune complexes (CIC) was evaluated. Heat-aggregated IgG (HAG) containing Clq (HAG:Clq) is used to generate standard curves for quantitation of CIC. Sera from 488 normal donors had an means of 3.

Characteristics of five monoclonal anti-alpha-fetoprotein antibodies.

Five monoclonal anti-alpha-fetoprotein (AFP) antibodies (IgG1) were isolated from six fusions. They were characterized by examining titration values, affinity constants, isotypes, and epitope binding. Employing an epitope-blocking procedure which was based on the exclusion of like antibodies, four of the five monoclonal antibodies were found to be different.