Rapid identification of human B-lymphocytes and monocytes with rhodamine-labeled Brucella melitensis

The bacterium Brucella melitensis has been shown to bind selectively to human B-lymphocytes. The specificity of this binding can be exploited in a rapid technique for the determination of human B-lymphocytes and monocytes by use of rhodamine-labeled Brucella melitensis. This fluorescent labeled regent is simple to use and provides highly specific identification of human B-lymphocytes and monocytes, as demonstrated in a series of experiments characterizing known cellular markers on T- and B-lymphocytes, their separated cellular subpopulations and lymphoblastoid cell lines. The use of fluorescence conjugated bacteria greatly simplifies the application of this highly specific technique and makes its use more practical in routine screening for B-cell and monocyte populations.