Natural killer （NK） cells are bone marrow derived, large granular lymphocytes, comprising approximately 10% to 20% of the mononuclear cell fraction in normal peripheral blood. They form a part of the first line defe...Natural killer （NK） cells are bone marrow derived, large granular lymphocytes, comprising approximately 10% to 20% of the mononuclear cell fraction in normal peripheral blood. They form a part of the first line defense mechanism against tumoural and viral spreading^1-4 Unlike T and B cells, NK cells do not require gene rearrangement for assembly of their receptor genes; rather, NK cells discriminate potential target cells based on the levels of self major histocompatibility complex （MHC） class I expression on such cells^5.6 There are two kinds of NK cell receptors^2.7.8 Inhibitory receptors recognize MHC class I molecules and deliver a downregulatory signal that inactivates the lytic machinery of NK cells. Stimulatory receptors expressed by NK cells deliver an activation signal.展开更多
Human umbilical cord blood （CB） has recently been used as a source of stem cells in transplantation. NK cells derived from CB are the key effector cells involved in graft-versus-host disease （GVHD） and graft-versu...Human umbilical cord blood （CB） has recently been used as a source of stem cells in transplantation. NK cells derived from CB are the key effector cells involved in graft-versus-host disease （GVHD） and graft-versus-leukemia （GVL）. It was reported that the activity of CB NK cells was lower than that of adult peripheral blood （PB） NK cells. In this study, we analyzed the expression of some NK cell receptors and cytotoxicity-related molecules in CB and PB NK cells. The expressions of activating NK receptors, CD16, NKG2D and NKp46, did not show significant difference between CB and PB NK cells. But the expression of inhibitory receptor NKG2A/CD94 was significantly higher on CB NK cells. As to the effector function molecules, granzyme B was expressed significantly lower in CB NK cells, but the expressions of intracellular perforin, IFN-γ, TNF-α and cell surface FasL and TRAIL did not show difference between CB and PB NK cells. The results indicated that the high expression of NKG2A/CD94 and low expression of granzyme B may be related with the reduced activity of CB NK cells.展开更多
基金This study was supported by the grants from the "973" Program about the Development of National Significant Elementary Research (No. 2006CB504206)the Application Research Program of Prevention and Control of AIDS by Ministry of Health (NoWA2006-02) the National Natural Science Foundation of China (No. 30400383).
文摘Natural killer （NK） cells are bone marrow derived, large granular lymphocytes, comprising approximately 10% to 20% of the mononuclear cell fraction in normal peripheral blood. They form a part of the first line defense mechanism against tumoural and viral spreading^1-4 Unlike T and B cells, NK cells do not require gene rearrangement for assembly of their receptor genes; rather, NK cells discriminate potential target cells based on the levels of self major histocompatibility complex （MHC） class I expression on such cells^5.6 There are two kinds of NK cell receptors^2.7.8 Inhibitory receptors recognize MHC class I molecules and deliver a downregulatory signal that inactivates the lytic machinery of NK cells. Stimulatory receptors expressed by NK cells deliver an activation signal.
基金This work was supported by the National Natural Science Foundation of China （#30630059, #30528007, #30570819, #30571695, #30500467）Ministry of Science ＆ Technology of China （973 Basic Science Project #2003CB515501 #2006CB806504） and Ministry of Education of China （#705029）.
文摘Human umbilical cord blood （CB） has recently been used as a source of stem cells in transplantation. NK cells derived from CB are the key effector cells involved in graft-versus-host disease （GVHD） and graft-versus-leukemia （GVL）. It was reported that the activity of CB NK cells was lower than that of adult peripheral blood （PB） NK cells. In this study, we analyzed the expression of some NK cell receptors and cytotoxicity-related molecules in CB and PB NK cells. The expressions of activating NK receptors, CD16, NKG2D and NKp46, did not show significant difference between CB and PB NK cells. But the expression of inhibitory receptor NKG2A/CD94 was significantly higher on CB NK cells. As to the effector function molecules, granzyme B was expressed significantly lower in CB NK cells, but the expressions of intracellular perforin, IFN-γ, TNF-α and cell surface FasL and TRAIL did not show difference between CB and PB NK cells. The results indicated that the high expression of NKG2A/CD94 and low expression of granzyme B may be related with the reduced activity of CB NK cells.
