细胞因子诱导杀伤细胞／自然杀伤细胞培养过程中CD16及CD11a的表达变化

背景:由于细胞因子诱导杀伤细胞、自然杀伤细胞上表达的CD16和CD11a均与其介导的抗体依赖性细胞介导的细胞毒作用和直接接触杀伤的抗肿瘤效应密切相关.因此了解两种细胞扩增过程中这两种分子表达的强弱,对根据免疫效应细胞的最终用途决定两种细胞的最佳收获时机具有重要意义.目的:了解细胞因子诱导杀伤细胞和自然杀伤细胞在培养过程中的CD16和CD11a表达的变化规律.设计、时间及地点:细胞移植免疫学动态观察,于2006-09/2008-03在中山大学附属第二医院完成.材料:脐血来自本院健康足月妊娠产妇.方法:采用Ficoll-Hypaque法分离脐血单个核细胞,接种于含体积分数为0.15胎牛血清的IMDM,双抗生素青、链霉素各1×105U/L24孔培养板中,在培养体系中加入白细胞介素2、白细胞介素7、白细胞介素15、干细胞因子及FLT3L制备细胞因子诱导杀伤细胞和自然杀伤细胞,每隔3天半量换液及全量补充上述细胞因子.主要观察指标:流式细胞仪榆测CD3+CD56+细胞因子诱导杀伤细胞以及CD3-CD56+自然杀伤细胞在4周培养过程中CD16和CD11a表达的变化.结果:CD16在细胞因子诱导杀伤细胞、自然杀伤细胞上的表达随着培养时间的延长逐渐增加,在两类细胞上均在培养的第4周达到最高峰,分别为(55.99±3.90)%和(7.86±1.66)%,但CD16存自然杀伤细胞上表达比例较低,整个培养过程中自然杀伤细胞上CD16的均数表达没有超过8%.CD11a在细胞因子诱导杀伤细胞培养的第3周,自然杀伤细胞培养的第2周达到最高峰,分别为(49.32±6.32)%和(82.31±11.33)%,之后逐渐出现下降,到培养第4周几乎消失.结论:CD16和CD11a在细胞因子诱导杀伤细胞和自然杀伤细胞上的表达随培养时间呈动态变化,使用单克隆抗体联合细胞因予诱导杀伤细胞介导的抗体依赖性细胞介导的细胞毒作用效应时,细胞的收获期可在细胞培养的第4周,利用细胞因子诱导杀伤细胞和自然杀伤细胞的直接杀伤效应进行细胞过继免疫,那么收获细胞的时间以细胞培养的第3周为宜.     

IL-2和IL-15诱导扩增的脐带血NK细胞生物学特性研究

本研究探讨脐血CD3-CD56+NK细胞及其在IL-2、IL-15诱导扩增后的免疫表型、细胞毒活性等生物学特性的改变。分离脐血单个核细胞,在无血清培养条件下,分别加入IL-2或(和)IL-15,培养14 d,流式细胞术检测CD3-CD56+NK细胞亚群水平以及NK表面CD16、CD62L、NKG2D、NKG2A、NCR44、NCR46、颗粒酶B、穿孔蛋白的表达;用WST-1法检测NK细胞对K562细胞毒活性。结果表明,扩增14 d后IL-2、IL-15、IL-2/IL-15 3组NK细胞分别扩增了10.78±2.51、10.42±3.72、10.54±6.24倍,3组之间无显著差异;扩增后的NK细胞表达CD16的比例显著减低,IL-2和IL-15组之间差异显著;细胞因子扩增后CD62L表达无改变;IL-2有下调NKG2A、NCR46表达的作用,IL-15的作用则相反;两种细胞因子均有上调NKG2D、穿孔蛋白、NCR44表达的作用,且细胞因子之间也存在差异;IL-15有上调NK细胞颗粒酶B表达的作用;经细胞因子扩增的NK细胞毒活性显著增高,但细胞因子之间作用无显著差异。结论:在无血清培养条件下,IL-2和IL-15均能有效地扩增脐血中NK细胞。虽然2种细胞因子扩增后的CD3-CD56+NK细胞与功能相关的免疫表型呈现出不同的改变特征,但细胞毒活性均显著增加,且2种细胞因子之间作用无显著差别,协同作用不明显;NK细胞毒活性是各种活性分子共同作用的结果。     

Human herpesvirus-6 enhances natural killer cell cytotoxicity via IL-15.

The marked tropism of human herpesvirus-6 (HHV-6) for natural killer (NK) cells and T lymphocytes has led us to investigate the effect of HHV-6 on cellular cytotoxicity. We describe here how HHV-6 infection of peripheral blood mononuclear cells (PBMC) leads to upregulation of their NK cell cytotoxicity. The induction of NK cell activity by HHV-6 was abrogated by monoclonal antibodies (mAbs) to IL-15 but not by mAbs to other cytokines (IFN-alpha, IFN-gamma, TNF-alpha, TNF-beta, IL-2, IL-12) suggesting that IL-15 secreted in response to viral infection was responsible for the observed effect. Furthermore, NK activation by HHV-6 was blocked with mAb to CD122, as well as by human anti-HHV-6 neutralizing antibodies. Using RT-PCR, we were able to detect IL-15 mRNA upregulation in purified monocyte and NK cell preparations. IL-15 protein synthesis was increased in response to HHV-6. Finally, addition of IL-15 to PBMC cultures was found to severely curtail HHV-6 expression. Taken together, our data suggest that enhanced NK activity in response to viral infection represent a natural anti-viral defense mechanism aimed at rapidly eliminating virus-infected cells.     

Stimulation of natural killer cells with a CD137-specific antibody enhances trastuzumab efficacy in xenotransplant models of breast cancer

Trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2; also known as HER-2/neu), is indicated for the treatment of women with either early stage or metastatic HER2(+) breast cancer. It kills tumor cells by several mechanisms, including antibody-dependent cellular cytotoxicity (ADCC). Strategies that enhance the activity of ADCC effectors, including NK cells, may improve the efficacy of trastuzumab. Here, we have shown that upon encountering trastuzumab-coated, HER2-overexpressing breast cancer cells, human NK cells become activated and express the costimulatory receptor CD137. CD137 activation, which was dependent on NK cell expression of the FcγRIII receptor, occurred both in vitro and in the peripheral blood of women with HER2-expressing breast cancer after trastuzumab treatment. Stimulation of trastuzumab-activated human NK cells with an agonistic mAb specific for CD137 killed breast cancer cells (including an intrinsically trastuzumab-resistant cell line) more efficiently both in vitro and in vivo in xenotransplant models of human breast cancer, including one using a human primary breast tumor. The enhanced cytotoxicity was restricted to antibody-coated tumor cells. This sequential antibody strategy, combining a tumor-targeting antibody with a second antibody that activates the host innate immune system, may improve the therapeutic effects of antibodies against breast cancer and other HER2-expressing tumors.     

Innate and cytokine-driven signals, rather than microbial antigens, dominate in natural killer T cell activation during microbial infection

Invariant natural killer T cells (iNKT cells) are critical for host defense against a variety of microbial pathogens. However, the central question of how iNKT cells are activated by microbes has not been fully explained. The example of adaptive MHC-restricted T cells, studies using synthetic pharmacological α-galactosylceramides, and the recent discovery of microbial iNKT cell ligands have all suggested that recognition of foreign lipid antigens is the main driver for iNKT cell activation during infection. However, when we compared the role of microbial antigens versus innate cytokine-driven mechanisms, we found that iNKT cell interferon-γ production after in vitro stimulation or infection with diverse bacteria overwhelmingly depended on toll-like receptor-driven IL-12. Importantly, activation of iNKT cells in vivo during infection with Sphingomonas yanoikuyae or Streptococcus pneumoniae, pathogens which are known to express iNKT cell antigens and which require iNKT cells for effective protection, also predominantly depended on IL-12. Constitutive expression of high levels of IL-12 receptor by iNKT cells enabled instant IL-12-induced STAT4 activation, demonstrating that among T cells, iNKT cells are uniquely equipped for immediate, cytokine-driven activation. These findings reveal that innate and cytokine-driven signals, rather than cognate microbial antigen, dominate in iNKT cell activation during microbial infections.     

NKTR-255 is a polymer-conjugated IL-15 with unique mechanisms of action on T and natural killer cells

NKTR-255 is a PEG conjugate of recombinant human IL-15 (rhIL-15) being examined as a potential cancer immunotherapeutic. Since IL-15 responses can be mediated by trans or cis presentation via IL-15Rα or soluble IL-15/IL-15Rα complexes, we investigated the role of IL-15Rα in driving NKTR-255 responses using defined naive and memory OVA-specific CD8⁺ T cells (OT-I) and NK cells in mice. NKTR-255 induced a 2.5- and 2.0-fold expansion of CD8⁺ T and NK cells, respectively, in WT mice. In adoptive transfer studies, proliferation of naive and memory WT OT-I T cells in response to NKTR-255 was not impaired in IL-15Rα^−/− mice, suggesting trans presentation was not utilized by NKTR-255. Interestingly, naive IL-15Rα^−/− OT-I cells had deficient responses to NKTR-255, while memory IL-15Rα^−/− OT-I cell responses were partially impaired, suggesting that naive CD8⁺ T cells are more dependent on cis presentation of NKTR-255 than memory CD8⁺ T cells. In bone marrow chimera studies, IL-15Rα^−/− and WT NK cells present in WT recipients had similar responses to NKTR-255, suggesting that cis presentation is not utilized by NK cells. NKTR-255 could form soluble complexes with IL-15Rα; binding to murine IL-15Rα generated superagonists that preferentially stimulated NK cells, showing that conversion to IL-15Rβ agonist biases the response toward NK cells. These findings highlight the ability of NKTR-255 to utilize IL-15Rα for cis presentation and act as an IL-15Rαβ agonist on CD8⁺ T cells.     

Receptor-induced death in human natural killer cells: involvement of CD16

Propriocidal regulation of T cells refers to apoptosis induced by interleukin 2 (IL-2) activation with subsequent antigen receptor stimulation. We examined whether natural killer (NK) cells exhibited cytokine- and ligand-induced death similar to activated T cells. Peripheral NK cells were examined for ligand-induced death using antibodies to surface moieties (CD2, CD3, CD8, CD16, CD56), with and without prior activation of IL-2. Only those NK cells stimulated first with IL-2 and then with CD16 exhibited ligand-induced death; none of the other antibody stimuli induced this phenomenon. Next we examined various cytokines (IL-2, IL-4, IL-6, IL-7, IL-12, IL-13, interferon alpha and gamma) that can activate NK cells and determined if CD16- induced killing occurred. Only IL-2 and IL-12 induced NK cell death after occupancy of this receptor by aggregated immunoglobulin or by cross-linking with antireceptor antibody. The CD16-induced death was inhibited by herbimycin A, indicating that cell death was dependent upon protein tyrosine kinases. Identical to T cells, the form of cell death for NK cells was demonstrated to be receptor-induced apoptosis. Overall these data indicate that highly activated NK cells mediate ligand-induced apoptosis via signaling molecules like CD16. Whereas the propriocidal regulation of T cells is antigen specific, this is not the case for NK cells due to the nature of the receptor. The clinical implications of this finding are considered.     

Cytokine gene therapy using adenovirally transduced, tumor-seeking activated natural killer cells

We previously demonstrated that adoptively transferred, interleukin (IL)-2-activated natural killer (A-NK) cells are effective in reducing B16 lung tumors in tumor-bearing animals. This effect depends on high and often toxic doses of IL-2 to support the survival and antitumor functions of the transferred A-NK cells. We hypothesized that A-NK cells transduced to express pro-NK cell cytokines would become less dependent on high and potentially toxic amounts of IL-2. Here, we demonstrate that A-NK cells adenovirally transduced to express mIL-12 survive well and function efficiently in mice bearing B16 lung tumors when supported with low, nontoxic doses of IL-2. The intratumoral survival of nontransduced "bystander' A-NK cells also increased when they were coinjected with IL-12 gene-transduced A-NK cells. The enhanced survival of exogenously delivered, IL-12 gene-transduced A-NK cells resulted in greater antitumor responsiveness. This led to a 7- to 10-day increase in median survival time compared with tumor-bearing mice receiving mock-transduced A-NK cells. These data show that the presence of IL-12 around tumor-infiltrating A-NK cells enhances their antitumor activity while reducing their requirement for systemically administered IL-2.     

NK 细胞上清液提高CTL 细胞对肝癌细胞杀伤力的研究

目的：研究用白细胞介素2（IL‐2）联合IL‐12、IL‐18以及三者共同活化NK细胞所提取的上清液与肝癌细胞共培养是否能提高AFP特异性的细胞毒性T细胞（CTL）对小鼠肝癌细胞的杀伤性。方法提取NK 细胞,分别用IL‐26000 IU／mL、IL‐26000 IU／mL＋ IL‐1210 ng／mL、IL‐26000 IU／mL＋IL‐l8100 ng／mL、IL‐26000 IU／mL＋IL‐1210 ng／mL＋IL‐18100 ng／mL活化NK细胞,3 d后提取上清液,ELISA检测上清液IFNγ表达量,然后将上清液与Hepa1‐6细胞培养过夜,流式细胞仪检测肿瘤细胞表面I类组织相容性抗原（M HC I）表达,以其为靶细胞检测AFP特异性的CTL细胞对 Hepa1‐6细胞杀伤率。结果NK＋IL‐2＋IL‐12、NK＋IL‐2＋IL‐18、NK＋IL‐2＋IL‐12＋IL‐18上清液的IFNγ含量高于NK＋IL‐2上清液的IFNγ含量（P＜0．05）,并且上述三组能有效提高小鼠 Hepa1‐6细胞表面M HC I的表达（P＜0．05）,从而显著提高了AFP特异性的CTL细胞对靶细胞的杀伤活性,然而阻断IFNγ分泌,AFP特异性的CTL细胞对靶细胞的杀伤活性降低。结论 NK 细胞上清液能够增强AFP特异性的CTL对肝癌细胞的杀伤作用。     

Posttransplant adoptive immunotherapy with activated natural killer cells in patients with metastatic breast cancer

Relapse after high-dose chemotherapy is the main cause of therapeutic failure in patients with metastatic breast cancer. Adoptive immunotherapy with interleukin-2 (IL-2) plus activated natural killer cells may eliminate residual disease without excessive toxicity. The authors sought to determine if immunotherapy immediately after transplantation would affect engraftment and the toxicity associated with transplantation. Fifteen consecutive patients with metastatic breast cancer were allocated to three cohorts. Cohort 1 (five patients) received high-dose cyclophosphamide, thiotepa, and carboplatin (CTCb) followed by peripheral blood stem cell infusion and granulocyte colony-stimulating factor at 10 micrograms/kg. Cohort 2 (five patients) received in addition rhIL-2 (2 x 10(6) IU/m2/day) for 4 days intravenously via continuous infusion after peripheral blood stem cell infusion. In cohort 3 (five patients), peripheral blood stem cell transplant was followed by infusion of autologous activated NK cells and rhIL-2 (2 x 10(6) IU/m2/day) for 4 days (via continuous intravenous infusion). Generation of activated NK cells was possible in all patients in cohort 3. All patients has successful engraftment. Median time to absolute neutrophil count more than 0.5 x 10(9)/L was 8 days (range, 8 to 11 days) in cohort 1, 9 days (range, 7 to 11 days) in cohort 2, and 9 days (range, 8 to 9 days) in cohort 3. Median time until the platelet count was more than 20 x 10(9)/L was 14 days (range, 9 to 22 days) in cohort 1, 11 days (range, 6 to 14 days) in cohort 2, and 12 days (range, 11 to 21 days) in cohort 3. All patients developed neutropenic fevers, but the overall toxicity associated with the infusion of IL-2 (cohort 2) or IL-2 plus activated NK cells (cohort 3) did not differ from that observed in cohort 1. Complete responses were achieved in one patient in cohort 1, in two patients in cohort 2, and in one patient in cohort 3. In conclusion, post-transplant adoptive immunotherapy with activated NK cells plus IL-2 is feasible, well tolerated, and does not adversely affect engraftment.     

Antiviral CD4+ memory T cells are IL-15 dependent

Survival and intermittent proliferation of memory CD4(+) and CD8(+) T cells appear to be controlled by different homeostatic mechanisms. In particular, contact with interleukin (IL)-15 has a decisive influence on memory CD8(+) cells, but not memory CD4(+) cells. Past studies of memory CD4(+) cells have relied heavily on the use of naturally occurring memory phenotype (MP) cells as a surrogate for antigen (Ag)-specific memory cells. However, we show here that MP CD4(+) cells contain a prominent subset of rapidly proliferating major histocompatibility complex (MHC) II-dependent cells. In contrast, Ag-specific memory CD4 cells have a slow turnover rate and are MHC II independent. In irradiated hosts, these latter cells ignore IL-15 and expand in response to the elevated levels of IL-7 in the lymphopenic hosts. In contrast, in normal nonlymphopenic hosts where IL-7 levels are low, memory CD4 cells are heavily dependent on IL-15. Significantly, memory CD4(+) responsiveness to endogenous IL-15 reflects marked competition from other cells, especially CD8(+) and natural killer cells, and increases considerably after removal of these cells. Therefore, under normal physiological conditions, homeostasis of CD8(+) and CD4(+) memory cells is quite similar and involves IL-15 and IL-7.     

IL-12 enhances the natural killer cell cytokine response to Ab-coated tumor cells

The anti-tumor activity of recombinant mAb's directed against tumor cell growth receptors has generally been considered to result from direct antiproliferative effects, the induction of apoptosis, or possibly Ab-dependent cellular cytotoxicity mediated against tumor targets. However, it remains unclear to what degree these mechanisms actually aid in the clearance of Ab-coated tumor cells in vivo. We show here that NK cells secrete a distinct profile of potent immunostimulatory cytokines in response to dual stimulation with Ab-coated tumor cells and IL-12. This response could not be duplicated by costimulation with other ILs and was significantly enhanced in the presence of monocytes. Cytokine production was dependent upon synergistic signals mediated by the activating receptor for the Fc portion of IgG (FcgammaRIII) and the IL-12 receptor expressed on NK cells. Coadministration of Ab-coated tumor cells and IL-12 to BALB/c mice resulted in enhanced circulating levels of NK cell-derived cytokines with the capacity to augment anti-tumor immunity. These findings suggest that, in addition to mediating cellular cytotoxicity and apoptosis, the anti-tumor activity of mAb's might also result from activation of a potent cytokine secretion program within immune effectors capable of recognizing mAb-coated targets.     

Reversible defects in natural killer and memory CD8 T cell lineages in interleukin 15-deficient mice

C57BL/6 mice genetically deficient in interleukin 15 (IL-15(-/-) mice) were generated by gene targeting. IL-15(-/-) mice displayed marked reductions in numbers of thymic and peripheral natural killer (NK) T cells, memory phenotype CD8(+) T cells, and distinct subpopulations of intestinal intraepithelial lymphocytes (IELs). The reduction but not absence of these populations in IL-15(-/-) mice likely reflects an important role for IL-15 for expansion and/or survival of these cells. IL-15(-/-) mice lacked NK cells, as assessed by both immunophenotyping and functional criteria, indicating an obligate role for IL-15 in the development and functional maturation of NK cells. Specific defects associated with IL-15 deficiency were reversed by in vivo administration of exogenous IL-15. Despite their immunological defects, IL-15(-/-) mice remained healthy when maintained under specific pathogen-free conditions. However, IL-15(-/-) mice are likely to have compromised host defense responses to various pathogens, as they were unable to mount a protective response to challenge with vaccinia virus. These data reveal critical roles for IL-15 in the development of specific lymphoid lineages. Moreover, the ability to rescue lymphoid defects in IL-15(-/-) mice by IL-15 administration represents a powerful means by which to further elucidate the biological roles of this cytokine.     

Coordinate expression and trans presentation of interleukin (IL)-15Ralpha and IL-15 supports natural killer cell and memory CD8+ T cell homeostasis

The high affinity interleukin (IL)-15 receptor, IL-15Ralpha, is essential for supporting lymphoid homeostasis. To assess whether IL-15Ralpha's role in vivo is to trans present IL-15, we generated mixed bone marrow chimera from IL-15Ralpha- and IL-2/15Rbeta-deficient mice. We find that IL-15Ralpha-competent, IL-2/15Rbeta-deficient cells are able to support IL-15Ralpha-deficient natural killer (NK) and memory CD8+ T cells, thus ruling out secondary signals on these cells and demonstrating that IL-15Ralpha-mediated presentation of IL-15 in trans is the primary mechanism by which IL-15Ralpha functions in vivo. Surprisingly, using IL-15- and IL-15Ralpha-deficient mixed chimera, we also find that IL-15 and IL-15Ralpha must be expressed by the same cells to present IL-15 in trans, indicating that IL-15Ralpha is required on a cellular level for the elaboration of IL-15. These studies indicate that IL-15Ralpha defines homeostatic niches for NK and memory CD8+ T cells by controlling both the production and the presentation of IL-15 in trans to NK and CD8+ memory T cells.     

The role of natural killer cells and lymphokine activated killer cells in the pathogenesis of hepatic injury in hepatitis A [corrected]

In order to clarify the mechanism of liver damage in hepatitis A, we studied the role of Natural Killer (NK) cells and Lymphokine Activated Killer (LAK) cells in non-specific immunological reactions using hepatitis A (HAV) infected cells (JTC-12.P3 cell) using the 51Cr release assay. No significant difference in specific cytotoxicity was observed between uninfected cells (JTC) and HAV-infected cells (JTC-HAV) to fresh and Poly I:Cor rIL-2 pretreated peripheral blood mononuclear cells (PBMC) from healthy donors or patients with acute hepatitis A. But in an experiment employing fresh and rIL-2 pretreated PBMC from cynomolgus monkey as effectors, a significant difference in NK and LAK sensitivity between JTC and JTC-HAV was noticed. Cytotoxicity assay was then carried out using as effectors fresh or rIL-2 pretreated cells of B, NK and T cell fractions obtained after separation of PBMC from monkey by the E-rosette formation method. Both fresh and rIL-2 pretreated B/NK cells showed significantly higher cytotoxicity for JTC-HAV than JTC, but neither fresh or rIL-2 pretreated T cells showed cytotoxicity for JTC-HAV or JTC. These results imply that both NK and LAK cells may play a part in the mechanism of hepatocellular injury.     

Endogenous production of interleukin 15 by activated human monocytes is critical for optimal production of interferon-gamma by natural killer cells in vitro.

Natural killer (NK) cells are large granular lymphocytes that constitutively express functional IL-2 receptors. We have shown that recombinant human IL-15 uses the IL-2 receptor to activate human NK cells and can synergize with recombinant human IL-12 to stimulate NK cell production of IFN-gamma in vitro. IFN-gamma production by NK cells is critical in the prevention of overwhelming infection by obligate intracellular microbial pathogens in several experimental animal models. Herein, we demonstrate that human monocytes produce IL-15 protein within 5 h of activation with LPS. Using an IL-15-neutralizing antiserum in a coculture of LPS-activated monocytes and NK cells, we demonstrate that monocyte-derived IL-15 is critical for optimal NK cell production of IFN-gamma. Endogenous IL-15 activates NK cells through the IL-2 receptor, and with endogenous IL-12, regulates NK cell IFN-gamma after monocyte activation by LPS. These in vitro studies are the first to characterize a function for endogenous IL-15, and as such, suggest an important role for IL-15 during the innate immune response. IL-15 may be an important ligand for the NK cell IL-2 receptor in vivo.