Effects of Th1 and Th2 cytokines on the phagocytosis of Mycobacterium tuberculosis by human neutrophils / 中华微生物学和免疫学杂志

ABSTRACT

Objective To establish a flowcytometry method for detecting phagocysis of Mycobacterium tuberculosis(Mth) by the human peripheral blood neutrophils( PMNs), and to explore the effects of Thl and Th2 cytokine on phagocytotic activity of PMNs. Methods By using acid-fast staining the phagocytosis of Mtb by human neutrophil was observed by microscopy, and the phagocytosis of FTTC labeled Mtb by human neutrophils was detected under confocal microscope. The whole fresh peripheral blood of healthy adults was incubated with FTTC labeled Mtb and the phagocytosis were measured by flow cytometry. The altered phagocytosis of FTTC-Mtb by neutrophils pretreated with IL-2, IFN-γ, GM-CSF or IL-4 were measured. Results Human peripheral blood neutrophils activity of Mtb phagocytosis was observed by acid-fast staining and confocal microscope. The percentage of phagocytosis of Mtb was dependent on the time of incubation with Mtb. The percentages were 47% at 5 min and reached plateau about 66% ～72% at 15 min to 20 min.Pretreatment with different concentrations of IL-2 or IFN-γincreased the phagocytosis of Mtb by 76.7% and 75.2%, respectively; but pretreatment with IL-4 decreased the phagocytosis by 31.7%. Conclusion IL-2and IFN-γcan increase phagocytosis of Mth by neutrophils; while IL-4 can reduced neutrophil activity of phagocytosis of Mtb by human neutrophils, and demonstrate that Th1/Th2 type cytokins involve in regulating the acitvities of neutrophils anti-Mtb infection.