The Reversibility of the Reaction between Rabbit Antibody and Tobacco Mosaic Virus

Abstract

In a previous publication, (1) the reaction between tobacco mosaic virus (TMV) and rabbit antiserum was analyzed with the underlying assumption that the combination of virus and antibody was essentially irreversible. Although the data were compatible with this assumption and the subsequent hypothesis advanced, it was pointed out that they were also in harmony with the alternative concept of a reversible reaction. Additional evidence has now been obtained supporting the latter notion of a reversible TMV-antibody reaction. This communication will present the evidence suggesting reversibility and indicate that the reaction approaches an equilibrium state soon after the reagents are mixed. The difficulty in demonstrating an equilibrium between virus and antibody resides chiefly in the large size of the virus particle. Where size is not a problem, as with haptens, for example, competition experiments, studies employing equilibrium dialysis, or light scattering techniques, have yielded much quantitative data in support of an equilibrium hypothesis (2–5).