Clinical Immunology br stimulators neutrophil sources compon
Clinical Immunology 201 (2019) 4–14
stimulators, neutrophil sources, component patterns and action sites, such as neutrophils from tumors or the circulation, formation in vessels or tissues, and induction with BCG or others. Clarification of these roles await further exploration.
The protein components are mainly responsible for tumor inhibition and cellular immunity. In the current study, the inhibition phenotype on cancer cells was reversed by disrupting NETs with boiling, but not DNase, indicating that NETs proteins were involved in cytotoxicity. NETs contained diﬀerent proteins , however, investigation of all the proteins involved in NETs-mediated cytotoxicity was beyond the scope of this study. The damaging eﬀect of NETs has been attributed, at least in part, to histones, MPO and NE [23,45,46]. Although endothelial cell damage during extended co-culture with neutrophils was prevented by destroying the DNA backbone of NETs,  and DNase therapy has an improvement in airflow obstruction and respiratory exacerbations in partial cystic fibrosis patients, but digestion of DNA was not suﬃcient to abolish NETs cytotoxicity. As expected, denaturing NETs proteins reduced the cytokine promotion, while degradation of DNA reduced cytokine promotion in part. The possible immune eﬀects of residual CpG or the nucleic EPZ031686 protected by conjunct proteins after DNase-digestion cannot be ruled out. It has been reported that NETs activated DCs through Toll-like receptor 9 (TLR9), an intracellular receptor re-cognizing DNA,  but the role of TLR9 in NETs-mediated T cell priming was not demonstrated . Together, the eﬀects of inhibiting tumor cells and stimulating immunity are mainly dependent on NETs proteins.
In current study, we first corroborated that BCG activation induced neutrophils to form NETs. Then, BCG-induced NETs exerted cytotoxi-city, induced apoptosis and cell-cycle arrest, and inhibited migration in bladder tumor cells. Moreover, NETs activated PBMCs, as indicated by the higher expression of CD4 and Th1 cytokines. Our observations suggested the complex in vivo eﬀects, including direct eﬀects of NETs and indirect eﬀects from NETs-stimulated immunity. NETs contributed to recruitment of T cells and monocytes-macrophages, and tissue da-mage, thus preventing tumor growth. Further experiments are war-ranted to clarify the mechanisms and examine the roles of NETs in pathologic responses.
K Liu, E Sun and M Lei were responsible for the coordination of the project and contributed to study design. The writing team consisted of K Liu, M Lei and E Sun. L Li, J Gao, X Nian, and L Wang performed ex-periments and data analysis. All authors read and approved the final manuscript.
Declarations of interest
Conflict of interest
The authors declare no potential conflicts of interest.
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