Use of monoclonal antibodies to identify thymopoietin in cultured human thymic epithelial cells.

Murine monoclonal antibodies (mAbs) were developed to discriminate thymopoietin, a human thymic hormone, and thysplenin, a closely related molecule found in spleen. Three of these recognized both native and synthetic thymopoietin as well as thysplenin. Together they define two non-overlapping epitopes which withstand sodium dodecyl sulfate denaturation and can be detected by western blotting. We used these three mAbs to demonstrate the production of thymopoietin by cultured thymic epithelial cells for up to several weeks. Three additional mAbs were selective for thysplenin. Highly specific mAbs will be useful for characterizing further these physiologically distinct polypeptides.

An avidin-biotin ELISA assay for the measurement of de novo human IgE synthesis in culture supernatants.

A very sensitive (100 pg/ml) solid-phase enzyme immunoassay (ELISA) for the determination of human IgE has been developed. This assay incorporates the avidin-biotin system to increase sensitivity and can detect as little as 100 pg/ml (10 pg/test) of human IgE. The assay is highly specific and allows quantitative determination of human IgE in supernatants of peripheral blood lymphocytes as well as in serum. The very high sensitivity of the assay was accomplished by optimizing concentrations of the following reagents: (1) affinity-purified rabbit anti-human IgE coating antibodies; (2) biotin-conjugated goat anti-human IgE; (3) avidin-horseradish peroxidase (HRP) conjugate. In summary, the assay described is rapid (6 h), reproducible, isotype specific, and has the sensitivity of radioimmunoassays usually employed for the quantification of IgE. This assay may be utilized in establishing concentrations of in vitro IgE levels synthesized by human peripheral blood lymphocytes (PBL).