MDP对烟曲霉孢子刺激A549细胞分泌TNF-α的影响

Objective To study the influence of MDP (specific ligand of NOD2) on the cytokine secretion by A549 cells stimulated with heat-killed conidia and the possible mechanisms. Methods (1) The cell lines A549 cells was incubated with Aspergillus fumigatus conidia and then the phagocytosis were examined with a transmission electron microscope(TEM) at different time points.（2）Real -time PCR was performed to study the expression of NOD2 mRNA in A549 cells after incubated with Aspergillus fumigatus conidia at different time points.（3）Immunofluorescence was also performed to examine the expressin of NOD2 protein in A549 cells after exposed to conidia 24 h .（4））Real -time PCR was performed to quantify the expression of TNF－α mRNA for evaluating the influence of MDP on the cytokine secretion by cells stimulated with heat-killed conidia. Results (1).The internalized heat-killed Aspergillus fumigatus conidia could be seen in A549 cells after10h of inculbation with conidia. (2). The expression of NOD2 mRNA was upregulated significantly after incubated with Aspergillus fumigatus conidia 24h compared with unstimulated cells（P＜0.05）（3）The expression of NOD2 protein was upregulated after exposed to Aspergillus fumigatus conidia 24h.（4）MDP combined with heat-killed conidia can significantly (P ＜0.05) increased the expression of TNF－αmRNA. Conclusions MDP stimulation can significantly increased the secretion of TNF－αin A549 cells incubated with Aspergillus fumigatus conidia. And the relationship between NOD2 proteins and the immune recognition of Aspergillus fumigatus conidia may be involved in this process.