Application of potassium thiocyanate as a destaining agent for confirming the specificity of viral immunofluorescence

A study was made of the destaining effects of various agents on measles-infected monolayers which were stained by the indirect method of immunofluorescence. It was found that KSCN, a chaotropic agent, gave the required destaining but was nonspecific in its action, removing antigen as well as adsorbed immunoglobulins. By using a KSCN-EDTA destaining solution, it was shown that two sequential restainings of infected monolayers were possible, which permitted the demonstration of the specificity of the observed immunofluorescence. The technique may be of particular use with clinical specimens in which relatively few cells give immunofluorescence and when the specificity of this fluorescence is questioned.