Inhibitory effects of TLR7 on Mycobacterium tuberculosis / 中国人兽共患病学报

ABSTRACT

ABSTRACTThe aim of the present study was to investigate the inhibitory effects of TLR7 on Mycobacterium tuberculosis . TLR7 on infected RAW264 .7 cells was activated by chemical synthesis of TLR7 activation motif ssRNA .Activated RAW264 .7 cells were inoculated with Mycobacterium tuberculosis ,quantitative PCR method was applied to detect the phagocytosis rate of cell to bacteria at different time after infection .Cytokine production was measured by ELISA from cell supernatant .Cells were cultured on Roche medium and counted after sterile cracked with TritonX‐100 and diluted with PBS .Scanning electronic micro‐scope ( SEM ) was applied to detect the morphological changes of cells treated with TLR7 activation motif ssRNA .The highest phagocytosis rate of bacteria of RAW264 .7 cells was at 3 hours post infection (P>0 .05) .Compared with that of the control group ,treatment after 36 hours intracellular bacterial quantity in ssRNA treated group was lower (P<0 .05) ,levels of IL‐12 (P<0 .05) and IL‐4 (P<0 .05) were increased .For treatment after 48 hours ,level of IL‐4 (P<0 .05) was decreased ,and TNF‐α (P<0 .05) was increased .For treatment after 3 hours ,cell morphology of the ssRNA group was obviously better than the control group and appeared lots of phagosomes .Results suggested that TLR7 could enhance macrophages in killing Myco‐bacterium tuberculosis by forming phagosomes and regulating cytokines production ,and TLR7 activation motif ssRNA could be used in the treatment of tuberculosis .