Neutrophil activation by recombinant cytokines.

Interest in the use of recombinant cytokines for immunotherapy is increasing as more information becomes available on the influences of these products on effector cells (e.g., neutrophils) involved in the resistance of the host to disease. This review summarizes the information available on in vitro and in vivo activation of neutrophils by recombinant cytokines. The emerging theme is that various cytokines (e.g., colony-stimulating factors, interleukins, tumor necrosis factors, and interferons) have direct and often synergistic abilities that activate the neutrophil to have enhanced cytocidal activity towards microbial and cellular stimuli. Equally important (although less well studied), cytokines have been shown in some cases to enhance the function of neutrophils isolated from immunosuppressed animals. These neutrophils have depressed function, and influences of cytokines on these cells may be different from their influences on normal neutrophils. Only recombinant cytokine data are included in this review because of the potential for contamination of naturally produced cytokines with unknown biologically active substances.