Lack of anti-tumour reactivity despite enhanced numbers of circulating natural killer T cells in two patients with metastatic renal cell carcinoma

Natural killer T (NK T) cells play a central role as intermediates between innate and adaptive immune responses important to induce anti-tumour reactivity in cancer patients. In two of 14 renal cell carcinoma (RCC) patients, treated with interferon (IFN)-α, we detected significantly enhanced numbers of circulating NK T cells which were typed phenotypically and analysed for anti-tumour reactivity. These NK T cells were T cell receptor (TCR) Vα24/Vβ11(+), 6B11(+) and bound CD1d tetramers. No correlation was observed between NK T frequencies and regulatory T cells (T(regs)), which were also enhanced. NK T cells expressed CD56, CD161, CD45RO and CD69 and were predominantly CD8(+), in contrast to the circulating T cell pool that contained both CD4(+) and CD8(+) T cells, as is found in healthy individuals. It is unlikely that IFN-α triggered the high NK T frequency, as all other patients expressed low to normal NK T numbers. A parallel was observed in IFN-α-related increase in activation of NK T cells with that in conventional T and non-T cells. Normal interleukin (IL)-7, IL-12 and IL-15 plasma levels were found. In one of the patients sporadic NK T cells were detected at the tumour site. α-Galactosylceramide (αGalCer) stimulation of peripheral blood mononuclear cells or isolated NK T cell lines from both patients induced IFN-γ, but no IL-4 and no response towards autologous tumour cells or lysates. The clinical course of disease in both patients was not exceptional with regard to histological subtype and extent of metastatic disease. Therefore, despite a constitutive high peripheral frequency and in vitroαGalCer responsiveness, the NK T cells in the two RCC patients did not show anti-tumour responsiveness.     

The mechanism of development of acute lung injury in lethal endotoxic shock using alpha-galactosylceramide sensitization

The mechanism underlying acute lung injury in lethal endotoxic shock induced by administration of lipopolysaccharide (LPS) into alpha-galactosylceramide (alpha-GalCer)-sensitized mice was studied. Sensitization with alpha-GalCer resulted in the increase of natural killer T (NK T) cells and the production of interferon (IFN)-gamma in the lung. The IFN-gamma that was produced induced expression of adhesion molecules, especially vascular cell adhesion molecule-1 (VCAM-1), on vascular endothelial cells in the lung. Anti-IFN-gamma antibody inhibited significantly the VCAM-1 expression in alpha-GalCer-sensitized mice. Very late activating antigen-4-positive cells, as the counterpart of VCAM-1, accumulated in the lung. Anti-VCAM-1 antibody prevented LPS-mediated lethal shock in alpha-GalCer-sensitized mice. The administration of LPS into alpha-GalCer-sensitized mice caused local production of excessive proinflammatory mediators, such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and nitric oxide. LPS caused microvascular leakage of proteins and cells into bronchoalveolar lavage fluid. Taken together, sensitization with alpha-GalCer was suggested to induce the expression of VCAM-1 via IFN-gamma produced by NK T cells and recruit a number of inflammatory cells into the lung. Further, LPS was suggested to lead to the production of excessive proinflammatory mediators, the elevation of pulmonary permeability and cell death. The putative mechanism of acute lung injury in LPS-mediated lethal shock using alpha-GalCer sensitization is discussed.     

Mouse CD146/MCAM is a marker of natural killer cell maturation

CD146/melanoma cell adhesion molecule is an adhesion molecule expressed by endothelial cells and by a small fraction of activated T and B lymphocytes in humans. In order to analyze the pattern of CD146 expression in mouse leukocytes at steady-state conditions, we generated a set of novel rat anti-mouse CD146 monoclonal antibodies. CD146 expression was undetectable on monocytes, dendritic cells, T cells or B cells, but was expressed on about 30% of neutrophils and 60% of NK cells. Within murine lymphocytes, CD146 was defined as a novel NK-specific surface molecule. An increased percentage of CD146+ cells was found in the most mature CD27(-)CD11b+ NK cell subpopulation, which also displays higher expression of Ly49C/I, Ly49D and KLRG1 and lower expression of NKG2A/C/E molecules. CD146+ NK cells were found to be less cytotoxic and produce less IFN-gamma than CD146(-) NK cells upon stimulation with target cells or activating antibodies. These findings define CD146 as a marker of mouse NK cell maturation that may be used as an alternative to the combined use of CD27 and CD11b staining to detect final stages of NK cell maturation.     

Functional impairment in circulating and intrahepatic NK cells and relative mechanism in hepatocellular carcinoma patients

Functional defects in natural killer (NK) cells have been proposed to be responsible for the failure of anti-tumor immune responses. Whether and how NK cells are impaired in hepatocellular carcinoma (HCC) patients remain unknown. In this study, we found that HCC patients displayed a dramatic reduction in peripheral CD56^dimCD16^pos NK subsets compared with healthy subjects. A significant reduction of CD56^dimCD16^pos NK subsets was also found in tumor regions compared with non-tumor regions in the livers of these HCC patients. Both these peripheral and tumor-infiltrating NK cells exhibited poorer capacity to produce IFN-γ and kill K562 targets, which was further found to be associated with increased CD4⁺CD25⁺ T regulatory cells as we previously-described in HCC patients. Addition of Tregs from HCC patients efficiently inhibited the anti-tumor ability of autologous NK cells in vitro. These findings are helpful for understanding the mechanism of NK cell-mediated anti-tumor immune responses in HCC patients.     

抗NKG2D多克隆抗体抑制NK和LAK细胞细胞毒效应的研究

目的 :分析抗NKG2D多克隆抗体 ( pAb)对NK和LAK细胞毒作用的影响。方法 :应用密度梯度离心法分离外周血单个核细胞 (PBMC) ,经 10mg/LPHA和 1× 10 6U/LrhIL 2诱导LAK细胞产生 ,再应用流式细胞术 (FCM)分选NK细胞并进行表型检测。加入抗NKG2DpAb封闭NK和LAK细胞表面的NKG2D分子后 ,用MTT比色法检测其细胞毒效应。结果 :经FCM分析证实 ,获得高纯度、高活性的NK细胞。抗NKG2DpAb能显著抑制NK和LAK细胞对K5 6 2、HepG2细胞的细胞毒效应。NK细胞对两种靶细胞的细胞毒效应分别下降了 82 .9%和 75 .6 % ;LAK细胞对两种靶细胞的细胞毒效应分别下降了 5 2 .8%和 5 0 .2 %。但抗NKG2DpAb不能显著抑制两种效应细胞对人鼻咽癌细胞系CNE的细胞毒效应。结论 :抗NKG2DpAb可通过封闭NK和LAK细胞表面的NKG2D分子 ,抑制其对肿瘤细胞的细胞毒效应     

Phage display-derived recombinant antibodies with TCR-like specificity against alpha-galactosylceramide and its analogues in complex with human CD1d molecules

The glycolipid alpha-galactosylceramide (alpha-GalCer) is a potent activator of invariant natural killer T (iNKT) cells and has been shown to be an effective agent against cancer, infections and autoimmune diseases. The effectiveness of alpha-GalCer and its alkyl chain analogues depends on efficient loading and presentation by the antigen-presenting molecule CD1d. To monitor the ability of CD1d to present the glycolipids, we have used a phage display strategy to generate recombinant antibodies with T cell receptor-like (TCRL) specificity against the human CD1d (hCD1d)-alpha-GalCer complex. These Fab fragments were able to detect specifically hCD1d-alpha-GalCer complexes in cell-free systems such as surface plasmon resonance and ELISA, as well as on the surface of hCD1d(+) antigen-presenting cells (APC) by flow cytometry and immunofluorescence microscopy, the latter of which could also detect intracellular complexes. We show that our TCRL antibodies can stain dendritic cells from CD11c-hCD1d-transgenic mice administered in vivo with alpha-GalCer and its analogues. Furthermore, the antibody was also able to detect the presentation by hCD1d molecules of analogues of alpha-GalCer with the same polar head structure. Using this reagent, we were able to confirm directly that the alpha-GalCer analogue C20:2 preferentially loads onto cell surface CD1d rapidly without the need for internalization, while the loading of alpha-GalCer is improved with longer incubation times on professional APC. This reagent will be essential for assessing the loading and presenting capabilities of hCD1d of alpha-GalCer and its analogues.     

Cytokine and surface receptor diversity of NK cells in resistant C3H/HeN and susceptible BALB/c mice with chronic Pseudomonas aeruginosa lung infection

The purpose of the present study was to investigate whether NK cells from resistant C3H/HeN mice and susceptible BALB/c mice showed different release of cytokines and expression of surface molecules during chronic P. aeruginosa lung infection using alginate-embedded P. aeruginosa mimicking the infection in cystic fibrosis. Lung cell suspensions were depleted of lymphocytes by magnetic cell sorting. The concentrations of IFN-gamma, IL-1beta and GM-CSF were estimated by ELISA at day 1 and 2 after infection. Non-infected mice were used as controls. Flow cytometry was used to estimate the surface expression of the LFA-1 and Fc receptors on NK cells. At day 2, IFN-gamma levels increased in C3H/HeN mice but decreased in BALB/c mice. The GM-CSF levels increased only in the C3H/HeN mice at day 1 and 2. Surface expression of LFA-1 on the NK cells was higher in C3H/HeN mice at day 1 and 2. In contrast, the expression of Fc receptors was significantly lower on NK cells in C3H/HeN mice at day 1 and 2. In conclusion, the present results show phenotypic differences in NK cells in the two mice strains in chronic P. aeruginosa lung infection, indicating different modulating effects in the Th1/Th2 balance.     

Loss of the CD56hiCD16- NK cell subset and NK cell interferon-gamma production during antiretroviral therapy for HIV-1: partial recovery by human growth hormone

Previous studies have shown that human natural killer (NK) cells are lost from the periphery and are functionally suppressed during HIV-1 infection, and that the administration of highly active antiretroviral therapy (HAART) results in a recovery of NK cell numbers in HIV-1-infected individuals. However, despite this recovery, interleukin (IL)-2 + IL-12-driven interferon (IFN)-gamma production by NK cells has been shown to remain suppressed after HAART. Here we show that the innate immune factor IL-15 in combination with IL-12 is also unable to recover NK cell IFN-gamma production in HAART-treated individuals. Furthermore, we also demonstrate an imbalance in the distribution of CD56loCD16hi and CD56hiCD16- NK subsets after successful HAART, CD56hiCD16- cells being reduced substantially in HIV-1 patients on HAART. Treatment of patients with combined human growth hormone and antiretroviral therapy resulted in further enhancement in the absolute numbers and the proportion of NK cells in some individuals in the absence of parallel effects on CD4+ T cells. Furthermore, in these individuals HAART with growth hormone resulted in an enhancement of cytokine-driven NK cell activation and IFN-gamma production compared to the HAART-only baseline.     

非霍奇金淋巴瘤患者T细胞亚群、NK细胞检测的临床意义

目的：研究非霍奇金淋巴瘤（NHL）患者外周血T淋巴细胞亚群、NK细胞检测结果的变化与该病的关系及与慢性淋巴腺炎患者细胞免疫功能的不同变化。方法：采用流式细胞仪（FCM）检测非霍奇金淋巴瘤（NHL）患者、慢性淋巴腺炎及正常人外周血T淋巴细胞亚群比例、NK细胞的变化。结果：非雹奇金淋巴瘤患者与正常人比较总的T淋巴细胞、辅助性T淋巴细胞及CD4^＋／CD8^＋比值明显下降（P〈0．05），细胞毒性T淋巴细胞明显升高（P〈0．05），NK细胞则无明显变化（P〉0．05）。非霍奇金淋巴瘤患者与慢性淋巴腺炎患者比较，细胞毒性T淋巴细胞、NK细胞明显升高（P〈0.05），而总的T淋巴细胞、辅助性T淋巴细胞无明显改变（P〉0．05），CD4^＋／CD8^＋比值略有下降但无明显统计学意义。结论：非霍奇金淋巴瘤患者细胞免疫功能明显受到抑制，T细胞亚群及NK细胞的检测对NHL的诊断、治疗、预后判断有一定的临床价值。