Impact of TLR5 and NLRC4 activation on innate immune cells in mice / 中国免疫学杂志

ABSTRACT

Objective:To investigate the impact of recombinant flagellin targeting TLR5 and NLRC4 simultaneously or respectively on innate immune cells in mice. Methods: Induction,expression,purification and identification of recombiant FliC,which were FliC(activating both TLR5 and NLRC4);FliCΔ90-97(unable to activate TLR5),FliC-L3A(unable to activate NLRC4),FliCΔ90-97:L3A(unable to activate both TLR5 and NLRC4). The mice were divided into five groups,namely group FliC,FliC-L3A,FliCΔ90-97,FliCΔ90-97:L3A and PBS,which were injected with 100μl PBS or 10μg recombinant flagellin intraperitoneally,three mice in each group. 12 h later,the mice were executed using dislocation of cervical vertebra and the splenic and peritoneal cells were isolated. The spleen was grinded into single-cell suspension. The proportion of neutrophils,NK cells,DCs and the expression level of CD80 and CD86 on DCs were evaluated with flow cytometry. Results:Group FliC,group FliC-L3A and group FliCΔ90-97 shared the similar proportion of neutrophils in peritoneal cavity ( P>0. 05 ) , and all of which were significantly higher than group PBS and group FliCΔ90-97 ( P<0. 01),and NK cells also showed the similar trend. Compared with group FliCΔ90-97 and FliCΔ90-97:L3A,the mean fluorescence intensities(MFIs) of CD80 and CD86 in group FliC and FliC-L3A increased significantly(P<0. 01). The proportion of Treg in spleen was highest among all groups. Conclusion:Activation of TLR5 and NLRC4 had similar chemotaxis of neutrophils and NK cells. The ex-pression of CD80 and CD86 on DCs were upregulated after stimulation by flagellin and TLR5-dependent. Activation of TLR5,but not NLRC4,increased the proportion of Treg in spleen.