Neutrophilic Granule Protein Is a Novel Murine LPS Antagonist

Neutrophilic granule protein (NGP) was previously reported as a granular protein of neutrophils in mouse, but the function has not been known clearly. We found the presence of the possible signal peptide in NGP and validated this protein is circulating in the bloodstream. In our findings, NGP is being modified post-translationally in Golgi apparatus and endoplasmic reticulum, which is a universal character of secretory molecules with a signal peptide. The secreted NGP protein could be detected both in vitro and in vivo. NGP has sequence similarity with an antimicrobial protein cathelicidin, and we observed the aspect of inflammation of NGP. Interestingly, NGP interacts with the complex of LPS and LPS binding protein (LBP). This interaction blocks the binding of the complex of LPS and LBP to TLR4 and the downstream inflammatory signals. Furthermore, the inhibitory function of NGP against the inflammatory effect of LPS could be observed in both in vitro and in vivo. With these findings, we report NGP is a novel secretory protein to mask LPS and inhibit its function.

A bioassay method for human Granulocyte—Macrophage Colony stimulating factor with DMSO—induced HL60 cell line / 中国免疫学杂志

Based on the high level of human granulocyte—macrophage colony—stimulating factor(HGM—CSF)re-ceptor of HL60 cell line upon induction by DMSO,we developed a hioassay method for HGM—CSF with ahigher specificity and sensitivity.The sensitivity of this assay reached to 0.3ng/ml by selecting the optimalHL60 cell—induced time,cell density and GM—CSF—stimulated time.With this assay,we are able to quantifythe level of rHuGM—CSF as well as conditioned media from human bladder carcinoma cell line U5637 screatinga high level of GM—CSF.

A highly sensitive, modified assay for Interleukin-1 / 中国免疫学杂志

In this paper, we describe a highly sensitive, modified assay which takes advantage of the capacity of a mouse thymoma cell line EL4 subclone to produce high concentration of IL-2 upon stimulation by interleukin I (IL-1).The assay was generally performed in 2 stages which included IL-1-dependent IL-2 production and IL-2 biological activity assay, and took about 40 hours to complete. The sensitivity of this assay was got to be 10~(-2) ～10~(-4)U/ml (2.5～25?10~(-4)pg/ml, about 10~2～10~3 times more sensitive than that of the mouse thymocyte co-stimulated assay) by selecting the optimal serum concentration, EL 4 cell density, IL-1-induced time and EL4 supernatant dilution. The rapid one step assay was performed by co-culturing the EL4 cells with CTLL-2 cells. This rapid assay could be completed within 30 hours with sensitivity of 10~(-1)U/ml. The assay was not affected by high concentrations of rHuTNF- ?, rHuTNF- ? or rHuIL-6,and was only slightly affected by high concentrations of rHuIL-2, ConA, PHA,LPS and SEB, and much affected by A23187.