Effect of Iodine on Serological Specificity of Tobacco Mosaic Virus. ∗

Summary

The sensitive complement fixation reaction was used to detect antigenic differences between normal tobacco mosaic virus (TMV) and TMV treated with iodine in KI in such a manner as to oxidize SH groups or to form diiodotyrosine. No change in antigenicity was detected in TMV in which the SH groups had been oxidized to S-S. Oxidation past the S-S stage resulted in change in the weight of virus reacting optimally with antiserum. Virus in which tyrosine was converted to diiodotyrosine was only weakly effective in stimulating formation of antibodies in rabbits and reacted with antiserum to normal virus with a 32-fold drop in antiserum dilution end point. These serological differences are comparable to the serological differences occurring between strains of TMV.