Histocompatibility and Tumor Virus Antigens Identified on Cells Grown in Tissue Culture by Means of the Mixed Hemadsorption Reaction

Abstract

The mixed hemadsorption reaction, which essentially is a modification of the Coombs mixed antiglobulin reaction, has been used to demonstrate histocompatibility antigens determined by the H-2 locus on normal and neoplastic mouse cells grown in vitro. With this method hemadsorption was demonstrated with serum dilutions up to 1:100, while in contrast it was impossible to demonstrate H-2 antigens by indirect immunofluorescent staining or by an assay for cytotoxic antibody. Furthermore, it was possible to demonstrate viral and/or “tumor-specific” antigens on embryonic mouse fibroblasts which had been infected in vitro with the Moloney agent. This study provides confirmatory evidence for the persistence of histocompatibility antigens on cells which have been maintained in tissue culture for long periods of time. Estimates of the minimum amounts of antibody nitrogen detectable by this method have been made, and this may be in the range of 0.002 µg to 0.0002 µg of Ab N/ml. The sensitivity of the mixed hemadsorption reaction makes it particularly suited to the study of cell surface antigens whose concentration and geometric representation might otherwise render them undetectable.