Objective      To investigate the inhibitory effect of myeloid differentiation protein-2 mimetic peptide (MDMP) on the phagocytosis of macrophage to Gram-negative bacteria and on TNF-α and IL-6 secretion in this process.       Methods      Enhanced green fluorescent protein (EGFP) gene fragment was amplified from pEGFP-C3 plasmid by PCR. The prokaryotic expression vector pET-32a(+)-EGFP was constructed by gene recombination. After sequencing

Escherichia coli BL21 (DE3) PLysS was transformed with the vector to screen recombinant bacteria pET-32a(+)-EGFP-BL21 (DE3) PLysS (EGFP-BL21) with stable expression of EGFP. The expression of recombinant plasmid was induced with IPTG

and the phagocytic ability of RAW264.7 cells to EGFP-BL21 was detected by immunofluorescence assay and flow cytometry. And then

the effect of MDMP (1

10 and 100 μg/mL) on the phagocytosis of RAW264.7 cells to EGFP-BL21 was analyzed by flow cytometry

and the secretion of IL-6 and TNF-α was measured by ELISA.       Results      Recombinant Escherichia coli EGFP-BL21 with stable expression of EGFP was obtained. After pretreatment with MDMP

the phagocytosis of RAW264.7 cells to EGFP-BL21 was significantly inhibited

and the phagocytic index (PI) of the pretreatment group (10 and 100 μg/mL) was significantly lower than that of the positive control group (P0.01). Furthermore

MDMP (10 and  100 μg/mL) significantly decreased the secretion of TNF-α and IL-6 in EGFP-BL21-stimulated RAW264.7 cells.       Conclusion      MDMP pretreatment can inhibit the phagocytosis of RAW264.7 cells to Gram-negative bacteria

and reduce the secretion of inflammatory factors such as TNF-α and IL-6.