Cathepsin G 對多形核嗜中性白血球及單核球細胞免疫功能及生物活性的調控作用
Other Title
Functional modulation of cathepsin G on polymorphonulcear neutrophils and
mononuclear cells
mononuclear cells
Date Issued
2005
Date
2005
Author(s)
謝松洲
DOI
932314B002088
Abstract
Granular proteins of neutrophil have long been recognized as mediators of innate
host defense. Newly discovered evidence suggests that granular constituents may also
participate in adaptive immune response.
Cathepsin G (CG) is a highly cationic serine proteinase contained in the
azurophilic granules of human polymorphonuclear neutrophils (PMN). A number of
in vitro studies have revealed diverse putative functions of cathepsin G extracellularly
including: (1) antimicrobial activity (2) regulation of inflammatory responses (3)
degradation of extracellular matrix and (4) vasoregulation. However, its effect on
immunological functions of PMN and mononuclear cells (MNC) have been rarely
reported in the literature.
We use MTT test, RT-PCR, flow cytometry, ELISA and Western blot to
investigate the effects of cathepsin G on immunological functions of PMN and MNC.
We found that cathepsin G from 5 to 100 mU/ml did not affect the survival of PMN
and MNC but effectively inhibit the phagocytosis of PMN. In addition, cathepsin G
did not change the mRNA expression of inflammatory cytokines such as IL-1 β , IL-4,
IL-8, IL-10 and TNF-α in PMN. However, the expression of IL-2 and TNF-α mRNA
was suppressed by CG. At the same time, cathepsin G enhanced the IL-8 production
of PMN and MNC. The soluble IL-2 receptor of MNC was also increased by presence
of CG. It is conceivable that IL-8 derived from macrophage facilitates PMN
chemotaxis and activation. The increased release of soluble IL-2 receptor of T
lymphocyte represents an activation marker of T lymphocyte. Moreover, cathepsin G
could modulate cationic ion channel expression on the cell surface. CG increased the
Na+-K+-ATPase expression on the surface of PMN and MNC but suppressed renal
outer medulary K+ channel (ROMK1) and modestly increased epithelial sodium
channel (ENaC) expression in PMN. But the reverse finding in MNC was noted.
These results indicate CG exerts the immune regulation on PMN and MNC via the
biologically functional modulation. In addition to the protease activity, CG plays a
critical role in the adaptive immunity.
Publisher
臺北市：國立臺灣大學醫學院內科
Type
report
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