A nuclear staining artefact in immunofluorescence.

Fluorescent conjugates of normal or immune sera can give non-specific staining of nuclei under conditions which might well be met in routine immunofluorescence procedures. These include the use of stored microscopical preparations for staining, the storage of stained preparations after mounting and the use of conjugates which are concentrated or insufficiently purified by absorptions or other means. Most important for avoiding problems raised by the artefact is to be aware of its possible occurrence.