Conformational changes in the antigenic determinant of tobacco mosaic virus protein resulting from polymerization of the subunits

Abstract

The influence of polymerization on the antigenic specificity of tobacco mosaic virus protein was studied. Immunoelectrophoretic and Ouchterlony analyses performed at different temperatures revealed a number of distinct antigenic states correlated with different sized aggregates. Two alternative explanations were offered for the above observations. In one, the multideterminant hypothesis, it was assumed that each TMV subunit possessed a small number of unique antigenic sites. The number of such different sites available for combining with antibody changed as polymerization proceeded giving rise to an antigenically mixed population of aggregates. The second hypothesis assumed that a single determinant present on the surface of each subunit underwent a series of conformational changes as a result of polymerization. These conformational changes in the polypeptide chain were assumed to cause slight alterations in the antigenic configuration resulting in the generation of crossreactive antigens. The data presented were more compatible with the latter or single determinant hypothesis.