Effect of Merthiolate on Agar Gel Diffusion Precipitin Reactions with Foot-and-Mouth Disease Virus

Summary Merthiolate incorporated as a preservative into the agar used for the immunodiffusion analysis of FMDV and an infection-associated antigen caused the degradation of these components. The 140S virus particles were partially degraded to 12S protein subunits of the virus, and the precipitating activity of the infection-associated antigen was markedly reduced. Sodium azide had no deleterious effect on these antigenic components. Fractions obtained from the ultracentrifugation of FMDV on CsCl density gradients were analyzed on both Merthiolate and sodium azide agar. Evidence was obtained that particles occurred which were antigenically identical to the virus, but differed with respect to their density and their sensitivity to Merthiolate.