The formation of immunogenic RNA-antigen complexes in a cell-free system

Abstract

The formation of complexes between ribonucleic acid (RNA) and solubilized bacteriophage T2 in vitro is readily demonstrable. The ability to evoke antibody formation against T2 in lymph node cultures is not a property of all such complexes but rather is restricted to those formed in the presence of cell sap (100,000 g supernatant). Further requirements for the formation of immunogenic RNA-antigen complexes include the use of RNA and of cell sap derived from organs, tissues or cells implicated as functional in the immune response. The activity of cell sap resides in a thermolabile, nondialyzable fraction which is presumed to be protein. Kinetic studies and observations on optima of temperature and pH suggest an enzymatic process and the presumed substrate of the enzyme(s) is the antigen part of the complex. The antibody response elicited by suitable complexes formed in the cell-free system closely resembles that observed in response to RNA-antigen complexes extracted from peritoneal macrophages which had been incubated with intact T2 phage. This resemblance extends to magnitude of the response, its kinetics and class of the antibody formed.