Automated counting of T cell rosettes

Human T cell rosettes were enumerated using an automated particle counter, the Bio/Physics Cytograf 6300A. An electronic oscilloscope representation of particle absorbance and scatter of a focused laser beam allows the separation and enumeration of both rosetted and non-rosetted lymphocytes. Repeated cytograf sampling of a single rosette preparation gave highly reproducible results, and sampling from replicate tubes produced the same degree of variation as microscopic analysis. T cell rosettes prepared from 27 volunteers and compared by both methods of quantitation showed a high degree of correlation. This method can objectively measure at least 100 times as many cells for their rosette-forming capability as the tedious microscopic technique.