A radioimmunoassay specific for a murine leukemia virus structural protein, the gs antigen, detects an antigenic reactivity in normal murine cells in culture and natural tissues. The assay was shown to measure an antigen that is highly related to the virion protein as shown by absorption tests, immunoadsorbent chromatography, and by analysis of linearized dose-response curves. These findings co...

Concentrated medium obtained from cultures of a continuous thymus-derived mouse lymphoma cell line (WEHI-22.1) was found to inhibit a T-cell-dependent (antidonkey red blood cell), but not a T-cell-independent (anti-DNP) immune response in vitro. Passage of such a concentrate through an anti-mouse Ig immunoadsorbent column removed its inhibitory activity. It is suggested that the tumor cell Ig c...

Gastric-mucosal glycoproteins of sheep have been shown to express the blood-group-I and -i antigens. The highest blood-group-I activities were found in glycoproteins lacking in blood-group-A and -H activities. In antigenically very active glycoprotein preparations, approx. 25% of the macromolecules expressed various blood-group-I and -i antigens, and these could be enriched by affinity chromato...

Insoluble antigen and antibody derivatives were obtained when ethyl chloroformate was added to solutions of antigen or antibody. Evidence has been obtained to show that polymerization has occurred and that the protein molecules are linked covalently to one another. The immunoadsorbent properties of these insolubilized proteins were investigated. They were found to be efficient, specific, and st...