Abolition of non-specific fluorescent staining of eosinophils

We have described a method of blocking the non-specific fluorescent staining of granulocytes, particularly eosinophils, using prior treatment with Lendrum's phenol chromotrope 2-R stain. The results have been successful with anti-immunoglobulin antisera in rabbit, chicken, and human tissues. This method has the advantage of not employing a counter-stain which is itself fluorescent, such as Evans blue or rhodamine-labelled BSA, and has equal potential use in conjuction with rhodamine- and fluorescein-conjugated reagents.