Abstract: Process for identification and enumeration of B and T lymphocytes in an unseparated peripheral body sample comprises contacting the sample with two morphologically distinguishable bacteria, each of which is coated with an antibody specific to an antigen on one of the B or T cells. The presence of a B or a T cell is determined by rosette formation with the corresponding bacteria, as viewed under a microscope in a smear.

Abstract: A method for identification of cell subpopulations in a population of cells which are morphologically alike, based on the ability of selected strains of bacteria to bind to the cell surface when they are brought in close contact.Selected strains of naturally occurring or artificially obtained bacteria of different species or genuses, having an affinity to bind to different subpopulations of a cell mixture, are brought into contact by centrifugation or the like with a mixture of cells such as leukocytes, the mixture is resuspended and the cells having bacteria attached are identified under the microscope. The method is useful particularly for the identification of B cells, several subpopulations of T cells, and the differentiation among leukemic cell populations.