Flt3 Ligand Promotes the Generation of a Distinct CD34+Human Natural Killer Cell Progenitor That Responds to Interleukin-15

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3647-3657 ◽  
Author(s):  
Haixin Yu ◽  
Todd A. Fehniger ◽  
Pascal Fuchshuber ◽  
Karl S. Thiel ◽  
Eric Vivier ◽  
...  

Abstract Interleukin-15 (IL-15) is produced by human bone marrow (BM) stromal cells and can induce CD34+ hematopoietic progenitor cells (HPCs) to differentiate into CD56+CD3−natural killer (NK) cells in the absence of stromal cells. IL-15 mediates its effects by signaling through the β and γcchains of the IL-2/15 receptor (R). The c-kit ligand (KL), also produced by stromal cells, enhances the expansion of NK cells from CD34+ HPCs in the presence of IL-15, but alone has no ability to differentiate NK cells. Mice deficient in KL do not appear to have a quantitative deficiency in NK cells, suggesting that other stromal cell factors may contribute to NK cell expansion. Flt3 ligand (FL) is also produced by BM stromal cells and has homology with KL. Furthermore, mice with a targeted disruption of the FL gene have reduced numbers of NK cells. We evaluated here the effects of FL on human NK cell development and expansion from CD34+ HPCs. Like KL, FL significantly enhanced the expansion of NK cells from CD34+ HPCs in the presence of IL-15, compared with IL-15 alone. However, FL alone had no effect on NK cell differentiation. We therefore explored the mechanism by which FL promotes IL-15–mediated NK cell development. FL was found to induce IL-2/15Rβ (CD122) expression on CD34bright HPCs. The CD34brightCD122+ cell coexpressed CD38, but lacked expression of CD7, CD56, NK cell receptors (NKRs), or cytotoxic activity in the absence of IL-15. Using limiting dilution analysis in the presence of IL-15 alone, we demonstrated that the FL-induced CD34brightCD122+ HPCs had an NK cell precursor frequency 20- to 60-fold higher than the CD34dim/negCD122− HPCs and 65- to 235-fold higher than fresh CD34+ HPCs. KL had similar effects as FL, but induced a significantly lower percentage of CD34brightCD122+ cells (P ≤ .01). Both FL and KL also increased IL-15R transcript in CD34+ HPCs. Culture of CD34+ HPCs in FL or KL, followed by culture in IL-15 alone, induced expression of both C-type lectin and Ig-superfamily NKRs on CD56+ cells. These data collectively support a role for FL in early human NK cell development. FL or KL generate a unique CD34brightCD122+CD38+ human NK cell intermediate from CD34+ HPCs that lacks NK features yet is IL-15–responsive. IL-15 is then required for the induction of CD56 and NKRs, LGL morphology, cytotoxic activity, and the ability to produce abundant cytokines and chemokines.

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3647-3657 ◽  
Author(s):  
Haixin Yu ◽  
Todd A. Fehniger ◽  
Pascal Fuchshuber ◽  
Karl S. Thiel ◽  
Eric Vivier ◽  
...  

Interleukin-15 (IL-15) is produced by human bone marrow (BM) stromal cells and can induce CD34+ hematopoietic progenitor cells (HPCs) to differentiate into CD56+CD3−natural killer (NK) cells in the absence of stromal cells. IL-15 mediates its effects by signaling through the β and γcchains of the IL-2/15 receptor (R). The c-kit ligand (KL), also produced by stromal cells, enhances the expansion of NK cells from CD34+ HPCs in the presence of IL-15, but alone has no ability to differentiate NK cells. Mice deficient in KL do not appear to have a quantitative deficiency in NK cells, suggesting that other stromal cell factors may contribute to NK cell expansion. Flt3 ligand (FL) is also produced by BM stromal cells and has homology with KL. Furthermore, mice with a targeted disruption of the FL gene have reduced numbers of NK cells. We evaluated here the effects of FL on human NK cell development and expansion from CD34+ HPCs. Like KL, FL significantly enhanced the expansion of NK cells from CD34+ HPCs in the presence of IL-15, compared with IL-15 alone. However, FL alone had no effect on NK cell differentiation. We therefore explored the mechanism by which FL promotes IL-15–mediated NK cell development. FL was found to induce IL-2/15Rβ (CD122) expression on CD34bright HPCs. The CD34brightCD122+ cell coexpressed CD38, but lacked expression of CD7, CD56, NK cell receptors (NKRs), or cytotoxic activity in the absence of IL-15. Using limiting dilution analysis in the presence of IL-15 alone, we demonstrated that the FL-induced CD34brightCD122+ HPCs had an NK cell precursor frequency 20- to 60-fold higher than the CD34dim/negCD122− HPCs and 65- to 235-fold higher than fresh CD34+ HPCs. KL had similar effects as FL, but induced a significantly lower percentage of CD34brightCD122+ cells (P ≤ .01). Both FL and KL also increased IL-15R transcript in CD34+ HPCs. Culture of CD34+ HPCs in FL or KL, followed by culture in IL-15 alone, induced expression of both C-type lectin and Ig-superfamily NKRs on CD56+ cells. These data collectively support a role for FL in early human NK cell development. FL or KL generate a unique CD34brightCD122+CD38+ human NK cell intermediate from CD34+ HPCs that lacks NK features yet is IL-15–responsive. IL-15 is then required for the induction of CD56 and NKRs, LGL morphology, cytotoxic activity, and the ability to produce abundant cytokines and chemokines.


Blood ◽  
2009 ◽  
Vol 113 (11) ◽  
pp. 2470-2477 ◽  
Author(s):  
Il-Kyoo Park ◽  
Chiara Giovenzana ◽  
Tiffany L. Hughes ◽  
Jianhua Yu ◽  
Rossana Trotta ◽  
...  

Interleukin-15 (IL-15) is essential for natural killer (NK) cell differentiation. In this study, we assessed whether the receptor tyrosine kinase Axl and its ligand, Gas6, are involved in IL-15–mediated human NK differentiation from CD34+ hematopoietic progenitor cells (HPCs). Blocking the Axl-Gas6 interaction with a soluble Axl fusion protein (Axl-Fc) or the vitamin K inhibitor warfarin significantly diminished the absolute number and percentage of CD3−CD56+ NK cells derived from human CD34+ HPCs cultured in the presence of IL-15, probably resulting in part from reduced phosphorylation of STAT5. In addition, CD3−CD56+ NK cells derived from culture of CD34+ HPCs with IL-15 and Axl-Fc had a significantly diminished capacity to express interferon-γ or its master regulator, T-BET. Culture of CD34+ HPCs in the presence of c-Kit ligand and Axl-Fc resulted in a significant decrease in the frequency of NK precursor cells responding to IL-15, probably the result of reduced c-Kit phosphorylation. Collectively, our data suggest that the Axl/Gas6 pathway contributes to normal human NK-cell development, at least in part via its regulatory effects on both the IL-15 and c-Kit signaling pathways in CD34+ HPCs, and to functional NK-cell maturation via an effect on the master regulatory transcription factor T-BET.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3746-3746
Author(s):  
Tiffany L Hughes ◽  
Michael Brian Becknell ◽  
Aharon Freud ◽  
Susan E Schmidt ◽  
Jianhua Yu ◽  
...  

Abstract Developmental intermediates of human natural killer (NK) cells are found within secondary lymphoid tissue (SLT), and five distinct stages of these intermediates have been identified. While it is well documented that developing NK cells are reliant on interleukin (IL)-15 as a survival factor, it is likely that additional cytokines and growth factors are required for complete NK cell differentiation. Microarray transcriptional profiling of purified stage 1–4 cells from human tonsil and stage 4 and 5 cells from peripheral blood (PB) identified a developmental window of interleukin-1 receptor 1 (IL-1R1) messenger RNA (mRNA) expression restricted to stages 2 and 3. We confirmed this finding by quantitative RT-PCR, and analysis of IL-1R1 surface protein expression revealed that, on average, 81% of stage 3 immature NK cells are IL-1R1(+), whereas the majority of cells from stages 1, 2, and 4 are IL-1R1(−). When cultured in vitro with IL-1β, a physiologic ligand for IL-1R1, cells from all four stages died within 48 hours, consistent with an absolute requirement for IL-15 as a survival factor. However, the combination of IL-1β and IL-15 led to a significant and reproducible 4.64±−0.68–fold increase in stage 3 cell number over that seen with IL-15 alone (p < 0.0005). This phenomenon was completely restricted to stage 3 immature NK cells, and is attributed to increased proliferation. The effects of IL-1β were abrogated by a molar excess of IL-1 receptor antagonist (IL-1RA), a physiologic competitor for IL-1R1 binding. Collectively, our data indicate that IL-1R1 expression fluctuates dramatically during NK cell development, and that unique responses of IL-1R1(+) stage 3 cells to IL-1β and IL-15 govern the expansion of these immature NK cells. Our findings support a model in which IL-1β promotes stage 3 proliferation and survival in vivo, driving stage 3 cells to be the most prevalent NK cell intermediates within SLT.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2310-2310
Author(s):  
Martin Guimond ◽  
Aharon G. Freud ◽  
Hsiaoyin C. Mao ◽  
Bradley W. Blaser ◽  
Gerritt Gerritt Lagemann ◽  
...  

Abstract The mechanism underlying the robust expansion of natural killer (NK) cells during exogenous administration of FL is unknown. Endogenous IL-15 had no impact on the in vivo expansion of NK cell precursors during FL administration but was required for the FL-mediated expansion of mature NK cells in the spleen and blood. Studies performed using in vivo BM chimeras showed that cells derived from hematopoietic precursors (HPC), not stromal cells, provided the endogenous IL-15 required for mature NK cell expansion by FL administration. Exogenous administration of FL significantly increased both CD11b(+)CD11c(-) and CD11b(+)CD11c(+) populations but not their relatively abundant expression of IL-15 or IL-15 receptor alpha on a per cell basis. This increase preceded and correlated with NK cell expansion, the latter of which largely resulted from enhanced survival and proliferation of an existing pool of mature NK cells rather than increased de novo production of NK cells from bone marrow precursors. Finally, in vivo elimination of CD11c+ cells during the course of FL treatment significantly decreased NK cell expansion. In summary, FL administration increases NK cells in vivo by expanding antigen presenting cells which in turn provide the requisite IL-15 to enhance survival and proliferation of mature NK cells.


Blood ◽  
2014 ◽  
Vol 124 (26) ◽  
pp. 3905-3913 ◽  
Author(s):  
Queenie P. Vong ◽  
Wai-Hang Leung ◽  
Jim Houston ◽  
Ying Li ◽  
Barbara Rooney ◽  
...  

Key Points Normal maturation of human NK cells requires the expression of TOX2. TOX2 directly regulates the expression of T-BET during human NK cell development.


2021 ◽  
Vol 9 (4) ◽  
pp. e002193
Author(s):  
Sigrid P Dubois ◽  
Milos D Miljkovic ◽  
Thomas A Fleisher ◽  
Stefania Pittaluga ◽  
Jennifer Hsu-Albert ◽  
...  

BackgroundFull application of cytokines as oncoimmunotherapeutics requires identification of optimal regimens. Our initial effort with intravenous bolus recombinant human interleukin-15 (rhIL-15) was limited by postinfusional reactions. Subcutaneous injection and continuous intravenous infusion for 10 days (CIV-10) provided rhIL-15 with less toxicity with CIV-10 giving the best increases in CD8+ lymphocytes and natural killer (NK) cells. To ease rhIL-15 administration, we shortened time of infusion. Treatment with rhIL-15 at a dose of 3–5 µg/kg as a 5-day continuous intravenous infusion (CIV-5) had no dose-limiting toxicities while effector cell stimulation was comparable to the CIV-10 regimen.MethodsEleven patients with metastatic cancers were treated with rhIL-15 CIV-5, 3 µg (n=4), 4 µg (n=3), and 5 µg/kg/day (n=4) in a phase I dose-escalation study (April 6, 2012).ResultsImpressive expansions of NK cells were seen at all dose levels (mean 34-fold), including CD56bright NK cells (mean 144-fold for 4 µg/kg), as well as an increase in CD8+ T cells (mean 3.38-fold). At 5 µg/kg/day, there were no dose-limiting toxicities but pulmonary capillary leak and slower patient recovery. This led to our choice of the 4 µg/kg as CIV-5 dose for further testing. Cytolytic capacity of CD56bright and CD56dim NK cells was increased by interleukin-15 assayed by antibody-dependent cellular cytotoxicity (ADCC), natural cytotoxicity and natural killer group 2D-mediated cytotoxicity. The best response was stable disease.ConclusionsIL-15 administered as CIV-5 substantially expanded NK cells with increased cytotoxic functions. Tumor-targeting monoclonal antibodies dependent on ADCC as their mechanism of action including alemtuzumab, obinutuzumab, avelumab, and mogamulizumab could benefit from those NK cell expansions and provide a promising therapeutic strategy.Trial registration numbersNCT01572493, NCT03759184, NCT03905135, NCT04185220 and NCT02689453.


Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2625-2632 ◽  
Author(s):  
Francesco Colucci ◽  
Sandrine I. Samson ◽  
Rodney P. DeKoter ◽  
Olivier Lantz ◽  
Harinder Singh ◽  
...  

Abstract PU.1 is a member of the Ets family of transcription factors required for the development of various lymphoid and myeloid cell lineages, but its role in natural killer (NK) cell development is not known. The study shows that PU.1 is expressed in NK cells and that, on cell transfer into alymphoid Rag2/γc−/−mice, hematopoietic progenitors of PU.1−/−fetal liver cells could generate functional NK cells but not B or T cells. Nevertheless, the numbers of bone marrow NK cell precursors and splenic mature NK cells were reduced compared to controls. Moreover,PU.1−/− NK cells displayed reduced expression of the receptors for stem cell factor and interleukin (IL)-7, suggesting a nonredundant role for PU.1 in regulating the expression of these cytokine receptor genes during NK cell development.PU.1−/− NK cells also showed defective expression of inhibitory and activating members of the Ly49 family and failed to proliferate in response to IL-2 and IL-12. Thus, despite the less stringent requirement for PU.1 in NK cell development compared to B and T cells, PU.1 regulates NK cell differentiation and homeostasis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Gianchecchi ◽  
Domenico V. Delfino ◽  
Alessandra Fierabracci

Autoimmune diseases recognize a multifactorial pathogenesis, although the exact mechanism responsible for their onset remains to be fully elucidated. Over the past few years, the role of natural killer (NK) cells in shaping immune responses has been highlighted even though their involvement is profoundly linked to the subpopulation involved and to the site where such interaction takes place. The aberrant number and functionality of NK cells have been reported in several different autoimmune disorders. In the present review, we report the most recent findings regarding the involvement of NK cells in both systemic and organ-specific autoimmune diseases, including type 1 diabetes (T1D), primary biliary cholangitis (PBC), systemic sclerosis, systemic lupus erythematosus (SLE), primary Sjögren syndrome, rheumatoid arthritis, and multiple sclerosis. In T1D, innate inflammation induces NK cell activation, disrupting the Treg function. In addition, certain genetic variants identified as risk factors for T1D influenced the activation of NK cells promoting their cytotoxic activity. The role of NK cells has also been demonstrated in the pathogenesis of PBC mediating direct or indirect biliary epithelial cell destruction. NK cell frequency and number were enhanced in both the peripheral blood and the liver of patients and associated with increased NK cell cytotoxic activity and perforin expression levels. NK cells were also involved in the perpetuation of disease through autoreactive CD4 T cell activation in the presence of antigen-presenting cells. In systemic sclerosis (SSc), in addition to phenotypic abnormalities, patients presented a reduction in CD56hi NK-cells. Moreover, NK cells presented a deficient killing activity. The influence of the activating and inhibitory killer cell immunoglobulin-like receptors (KIRs) has been investigated in SSc and SLE susceptibility. Furthermore, autoantibodies to KIRs have been identified in different systemic autoimmune conditions. Because of its role in modulating the immune-mediated pathology, NK subpopulation could represent a potential marker for disease activity and target for therapeutic intervention.


Blood ◽  
2020 ◽  
Vol 135 (9) ◽  
pp. 629-637
Author(s):  
Michael T. Lam ◽  
Emily M. Mace ◽  
Jordan S. Orange

Abstract Natural killer cell deficiencies (NKDs) are an emerging phenotypic subtype of primary immune deficiency. NK cells provide a defense against virally infected cells using a variety of cytotoxic mechanisms, and patients who have defective NK cell development or function can present with atypical, recurrent, or severe herpesviral infections. The current pipeline for investigating NKDs involves the acquisition and clinical assessment of patients with a suspected NKD followed by subsequent in silico, in vitro, and in vivo laboratory research. Evaluation involves initially quantifying NK cells and measuring NK cell cytotoxicity and expression of certain NK cell receptors involved in NK cell development and function. Subsequent studies using genomic methods to identify the potential causative variant are conducted along with variant impact testing to make genotype-phenotype connections. Identification of novel genes contributing to the NKD phenotype can also be facilitated by applying the expanding knowledge of NK cell biology. In this review, we discuss how NKDs that affect NK cell cytotoxicity can be approached in the clinic and laboratory for the discovery of novel gene variants.


Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 260-269 ◽  
Author(s):  
KF Mangan ◽  
ME Hartnett ◽  
SA Matis ◽  
A Winkelstein ◽  
T Abo

Abstract To determine the role of natural killer (NK) cells in the regulation of human erythropoiesis, we studied the effects of NK-enriched cell populations on the in vitro proliferation of erythroid stem cells at three different levels of maturation (day 14 blood BFU-E, day 5–6 marrow CFU-E, and day 10–12 marrow BFU-E). NK cells were enriched from blood by Percoll density gradient centrifugation and by fluorescence- activated cell sorting (FACS), using the human natural killer cell monoclonal antibody, HNK-1. The isolated enriched fractions were cocultured with autologous nonadherent marrow cells or blood null cells and erythropoietin in a methylcellulose erythroid culture system. Cells from low-density Percoll fractions (NK-enriched cells) were predominantly large granular lymphocytes with cytotoxic activity against K562 targets 6–10-fold greater than cells obtained from high- density Percoll fractions (NK-depleted cells). In coculture with marrow nonadherent cells (NA) at NK:NA ratios of 2:1, NK-enriched cells suppressed day 5–6 CFU-E to 62% (p less than 0.025) of controls, whereas NK-depleted cells slightly augmented CFU-E to 130% of controls (p greater than 0.05). In contrast, no suppression of day 10–12 marrow BFU-E was observed employing NK-enriched cells. The NK CFU-E suppressor effects were abolished by complement-mediated lysis of NK-enriched cells with the natural killer cell antibody, HNK-1. Highly purified HNK- 1+ cells separated by FACS suppressed marrow CFU-E to 34% (p less than 0.025) and marrow BFU-E to 41% (p less than 0.025) of controls. HNK- cells had no significant effect on either BFU-E or CFU-E growth. NK- enriched cells were poor stimulators of day 14 blood BFU-E in comparison to equal numbers of NK-depleted cells or T cells isolated by E-rosetting (p less than 0.01). Interferon boosting of NK-enriched cells abolished their suboptimal burst-promoting effects and augmented their CFU-E suppressor effects. These studies provide evidence for a potential regulatory role of NK cells in erythropoiesis. The NK suppressor effect is maximal at the level of the mature erythroid stem cell CFU-E. These findings may explain some hypoproliferative anemias that develop in certain NK cell-activated states.


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