Upregulation of major histocompatibility complex class II, CD83, CD64, and CD14 on polymorphonuclear neutrophils stimulated with interleukin-15.

BACKGROUND AND PURPOSE Polymorphonuclear neutrophils (PMNs) act as a first line of defense against bacterial infections. Recent studies indicated that PMNs could act as antigen-presenting cells. The aim of this study was to detect the expression of major histocompatibility complex (MHC) class II and certain molecules and receptors (CD83, CD64, and CD14) on the surface of PMNs stimulated with interleukin (IL)-15. METHODS PMNs were isolated from heparinized whole blood of healthy volunteers. Cells were incubated for 48 h at 37 degrees C in a humidified incubator with 5% carbon dioxide. After incubation for 48 h with and without IL-15, surface molecules were assayed by cytofluorometry. RESULTS Stimulation with IL-15 produced an increase in the expression of MHC class II and upregulation of the costimulatory molecules CD83, the immunoglobulin G receptor CD64, and the lipopolysaccharide receptor CD14 on the surface of PMNs. CONCLUSIONS The expression of MHC class II, CD83, CD64, and CD14 indicates that PMNs may be involved in both innate and acquired immunity.