The ex vivo function and expression of function-associated antigens of peripheral blood neutrophils and monocytes.

The availability of recombinant human granulocyte and granulocyte-macrophage colony-stimulating factors (rhG-CSF and rhGM-CSF) has prompted many studies of the analysis of antigen expression and function of monocytes and neutrophils from patients receiving these factors as therapeutic agents. Preparatory procedures for leukocytes are known to alter antigen expression and so function. We therefore investigated the use of a novel procedure in which live leukocytes are analyzed by flow cytometry without isolation from blood. The expression levels of CD11b, CD13, CD14, CD16, and CD18 antigens and L-selectin (TQ1 and Leu-8 epitopes) on neutrophils and monocytes from 15 normal individuals were determined and compared with a previously used method in which the leukocytes were fixed and the erythrocytes lysed before analysis. Significant differences for the apparent expression of CD11b, CD18, and L-selectin were observed between the two methods. The reasons for this were investigated. Since the new method allowed analysis of live cells, we also investigated whether modulation of antigen expression could be determined following receptor agonist interaction. This was found to be easily achievable, and we advocate using the new procedure where possible for the ex vivo analysis of function and function-associated antigens on monocytes and neutrophils.