Cell recognition among blood leukocytes: a new theory for cell recognition.

Blood leukocytes exhibit specific cell type recognition. Neutrophils adhere to neutrophils, eosinophils to eosinophils, basophils to basophils and monocytes to monocytes. Rather large homotypic aggregates are formed. These are almost abolished by prior treatment of the cells with trypsin. It is assumed that a protein is involved in this type of cell recognition. Protein monomer-monomer interaction could provide the specificity required in homotypic aggregate formation.