Objective: To investigate the effects of lipid-associated membrane proteins (LAMPs) derived from Mycoplasma pneumoniae (M. pneumoniae) strains on the expression of heme oxygenase 1 (HO-1) in a human monocyte cell line (THP-1). Methods: THP-1 cells were in vitro cultured with different concentrations of LAMPs for different times. The cytotoxicity of LAMPs to THP-1 cells was analyzed by using lactate dehydrogenase (LDH) releasing test. The expression of HO-1 at protein and mRNA levels were detected by Western blot and real-time RT-PCR, respective...