147 CD155 blockade boosts alloreactive natural killer cell antitumor effects against osteosarcoma

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A160-A160
Author(s):  
Monica Cho ◽  
Madison Phillips ◽  
Longzhen Song ◽  
Amy Erbe ◽  
Christian Capitini
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Cancer Biology ◽  
Nk Cell ◽  
Allogeneic Bone ◽  
Cytotoxicity Assays ◽  
Allogeneic Bmt ◽  
The Impact

BackgroundPediatric patients with relapsed and refractory osteosarcoma have poor prognoses with few treatment options. Allogeneic bone marrow transplant (BMT) has not yet shown a graft-versus-tumor (GVT) effect for osteosarcoma. Natural killer (NK) cells demonstrate antitumor activity against osteosarcoma, but adoptively transferred NK cells have limited proliferation, cytotoxicity, and persistence in vivo. To enhance an NK-specific GVT effect, we propose blocking the poliovirus receptor CD155 checkpoint molecule, which is overexpressed on osteosarcoma and can engage both activating and inhibitory receptors on NK cells. The impact of CD155 blockade on GVT and graft-versus-host-disease (GVHD) is unknown.MethodsNK cells from C57BL/6 (B6) mice were expanded with recombinant IL-15/IL-15R and analyzed by flow cytometry. Cytotoxicity assays were performed with IL-15 expanded B6 NK cells and mKate2-expressing K7M2 murine osteosarcoma at a 1:1 ratio with blockade of CD155 and CD155 ligands. To test efficacy of NK cell infusion and CD155 blockade after allogeneic BMT, BALB/c mice were lethally irradiated, transplanted with allogeneic B6 bone marrow, and challenged with luciferase-expressing K7M2 on day 0. At day 7, mice received IL-15 expanded B6 NK cells intravenously with either anti-IgG control or anti-CD155 antibody intraperitoneally and IL-2 subcutaneously on days 7 and 11. Mice were monitored for tumor growth by bioluminescence, and toxicity by GVHD using weight loss and clinical scores.ResultsCompared to unexpanded murine NK cells, IL-15 expanded NK cells (n = 6) show increased expression of NKG2D (65.33 ± 10.77% NKG2D+, p = 0.0077; 1030 ± 177.0 MFI, p = 0.0101) and an increased ratio of the CD155 activating (CD226) to inhibitory (TIGIT) ligand expression (11.71 ± 4.121, p = 0.0362). In cytotoxicity assays with IL-15 expanded allogeneic murine NK cells (n = 3 replicates), CD155 blockade enhances K7M2 osteosarcoma lysis (60.62 ± 3.19%, p = 0.0189) compared to IgG control (29.01 ± 7.66%). CD226 blockade decreased tumor killing (10.62 ± 8.51%, p = 0.0053) compared to CD155 blockade. In vivo allogeneic murine NK cell infusion and anti-CD155 antibody treatment after allogeneic BMT decreased tumor area under the curve by 44.3% compared to IgG control, without exacerbating GVHD.ConclusionsThese findings demonstrate that blockade of CD155 enhances an allogeneic NK cell-specific GVT effect for osteosarcoma treatment without exacerbating GVHD. CD155 blockade has the potential to improve usage of allogeneic BMT and NK cell adoptive immunotherapy as a combination treatment for osteosarcoma, and perhaps other pediatric sarcomas.AcknowledgementsThis work was supported by grants from the National Institute of General Medical Sciences/NIH T32 GM008692 and Training in Cancer Biology Training Grant NIH T32 CA009135 (to MMC), St. Baldrick’s Stand up to Cancer (SU2C) Pediatric Dream Team Translational Research Grant SU2C-AACR-DT-27-17, NCI/NIH R01 CA215461, American Cancer Society Research Scholar Grant RSG- 18-104-01-LIB, and the Midwest Athletes Against Childhood Cancer (MACC) Fund (to CMC). SU2C is a division of the Entertainment Industry Foundation. Research grants are administered by the American Association for Cancer Research, the scientific partner of SU2C. The contents of this article do not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the US government.

Adoptive Infusion of Allogeneic KIR Ligand Mismatched NK Cells Reduce GVHD in an MHC Matched Allogeneic Stem Cell Transplantation Model.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1310-1310
Author(s):  
Andreas Lundqvist ◽  
Leigh Samsel ◽  
Michael Eckhaus ◽  
Ramaprasad Srinivasan ◽  
Yoshiyuki Takahashi ◽  
...  
Keyword(s):  
T Cell ◽  
Nk Cells ◽  
Murine Model ◽  
Nk Cell ◽  
Allogeneic Transplantation ◽  
Allogeneic Bone ◽  
Median Score ◽  
The Impact

Abstract Retrospective data suggest NK cells play a role in protecting recipients from graft versus host disease (GVHD) in the setting of killer IgG-like receptor (KIR) ligand incompatibility. In humans, this protective effect is most evident with MHC mismatched transplantation, usually following in vivo or in vitro T-cell depletion. In MHC mismatched murine transplant models, lethal GVHD is reduced following the adoptive infusion of KIR ligand mismatched NK cells; it is unknown whether NK cells can mediate similar protective effects following MHC matched transplantation. Therefore, we investigated the impact of adoptively infusing KIR ligand mismatched NK cells on GVHD in an MHC matched T-cell replete murine model of allogeneic transplantation. Balb/C recipient mice underwent allogeneic bone marrow (8 x 106 cells) and splenocyte (15 x 106 cells) transplantation from B10.d2 donors following 950cGy of irradiation. Allogeneic B10.d2 donor NK cells were first isolated by negative depletion using magnetic beads selecting for CD4, CD5, CD8a, CD19, Gr-1 and Ter-119, and then expanded over 4-6 days in vitro in DMEM media containing 10% FCS and 500U/ml of IL-2. NK cell subsets (KIR ligand matched vs. KIR ligand mismatched) were then isolated by flow cytometry into Ly49I/C+ NK cells (KIR ligand mismatched in the GVHD direction for Balb/C recipients) and Ly49A/G+ NK cells (KIR ligand matched for Balb/C recipients). On day +4, recipient mice received a single tail vein injection with either KIR ligand matched, KIR ligand mismatched or unsorted “bulk” NK cells (0.5–1.0 x 106 NK cells). All (9/9) control transplant recipients (no adoptive NK cell infusion) as well as recipients of Ly49A/G (KIR ligand matched) NK cells (13/13) developed skin GVHD, in contrast to 4/7 (57%, p=0.03) recipients of bulk NK cells and only a minority (13% [1/8], p < 0.01) of animals receiving KIR ligand mismatched NK cells. Using a cumulative clinical GVHD scoring system (total score = 9), overall GVHD was decreased in recipients of KIR ligand mismatched NK cells (median score = 0 at day +45) compared to mice that received KIR ligand matched NK cells (median score = 3; p = 0.15) or no NK cells (median score = 3; p= 0.12); no significant difference in survival was observed between cohorts. This murine model provides the first in vivo evidence that adoptively infused KIR ligand mismatched allogeneic NK cells reduce GVHD following T-cell replete MHC matched allogeneic transplantation. The impact of infusing multiple doses of KIR ligand mismatched NK cells on GVHD and their ability to induce a graft-vs-tumor effect in tumor bearing Balb/c mice is currently being evaluated.

Mechanism by Which Exogenous Administration of Flt3 Ligand (FL) Expands Natural Killer Cells In Vivo.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2310-2310
Author(s):  
Martin Guimond ◽  
Aharon G. Freud ◽  
Hsiaoyin C. Mao ◽  
Bradley W. Blaser ◽  
Gerritt Gerritt Lagemann ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Stromal Cells ◽  
Cell Expansion ◽  
De Novo ◽  
Nk Cell ◽  
Flt3 Ligand ◽  
Antigen Presenting

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.

Synergistic effects of in vivo depletion of Ly-49A and Ly-49G2 natural killer cell subsets in the rejection of H2b bone marrow cell allografts

Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 3840-3844 ◽  
Author(s):  
Arati Raziuddin ◽  
Michael Bennett ◽  
Robin Winkler-Pickett ◽  
John R. Ortaldo ◽  
Dan L. Longo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Bone Marrow Cell ◽  
Nk Cell ◽  
Synergistic Effects ◽  
Marrow Cell ◽  
Killer Cell ◽  
F1 Hybrids

Subsets of murine natural killer (NK) cells exist that express the Ly-49 family of molecules that recognize different major histocompatibility complex (MHC) determinants. Bone marrow transplantation studies were performed to examine the in vivo functions of 2 of these subsets. Subsets of Ly-49A and Ly-49G2 NK share specificity for the same MHC class 1 ligand, Dd, binding of which results in an inhibitory signal to the NK cell but allows them to lyse H2b targets in vitro. We therefore examined the ability of these subsets to reject H2b bone marrow cell allografts in lethally irradiated mice. Surprisingly, depletion of Ly-49A+ NK cells in BALB/c or B10.D2 mice (both H2d) had no effect on the rejection of H2b BMC. However, Ly-49A depletion did partially abrogate the ability of B10.BR (H2k) mice to reject H2ballografts. Although depletion of either Ly-49A+ or Ly-49G2+ NK cells alone had no effect on the ability of B10.D2 mice to reject H2b BMC, depletion of both subsets dramatically and synergistically abrogated rejection. Studies with various B10 congenic mice and their F1 hybrids indicate that this synergy between Ly49A and Ly4G2 depletion occurs in every instance. Thus, Ly-49A+ NK cells appear to play a role in the rejection H2b bone marrow allografts, but, in most strains of mice studied, Ly-49G2+ NK cells must also be eliminated. The putative roles of these NK cell subsets in clinical transplantation remains to be elucidated.

Synergistic effects of in vivo depletion of Ly-49A and Ly-49G2 natural killer cell subsets in the rejection of H2b bone marrow cell allografts

Blood ◽  
2000 ◽  
Vol 95 (12) ◽  
pp. 3840-3844 ◽  
Author(s):  
Arati Raziuddin ◽  
Michael Bennett ◽  
Robin Winkler-Pickett ◽  
John R. Ortaldo ◽  
Dan L. Longo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Bone Marrow Cell ◽  
Nk Cell ◽  
Synergistic Effects ◽  
Marrow Cell ◽  
Killer Cell ◽  
F1 Hybrids

Abstract Subsets of murine natural killer (NK) cells exist that express the Ly-49 family of molecules that recognize different major histocompatibility complex (MHC) determinants. Bone marrow transplantation studies were performed to examine the in vivo functions of 2 of these subsets. Subsets of Ly-49A and Ly-49G2 NK share specificity for the same MHC class 1 ligand, Dd, binding of which results in an inhibitory signal to the NK cell but allows them to lyse H2b targets in vitro. We therefore examined the ability of these subsets to reject H2b bone marrow cell allografts in lethally irradiated mice. Surprisingly, depletion of Ly-49A+ NK cells in BALB/c or B10.D2 mice (both H2d) had no effect on the rejection of H2b BMC. However, Ly-49A depletion did partially abrogate the ability of B10.BR (H2k) mice to reject H2ballografts. Although depletion of either Ly-49A+ or Ly-49G2+ NK cells alone had no effect on the ability of B10.D2 mice to reject H2b BMC, depletion of both subsets dramatically and synergistically abrogated rejection. Studies with various B10 congenic mice and their F1 hybrids indicate that this synergy between Ly49A and Ly4G2 depletion occurs in every instance. Thus, Ly-49A+ NK cells appear to play a role in the rejection H2b bone marrow allografts, but, in most strains of mice studied, Ly-49G2+ NK cells must also be eliminated. The putative roles of these NK cell subsets in clinical transplantation remains to be elucidated.

scholarly journals Humanized mouse model supports development, function, and tissue residency of human natural killer cells

2017 ◽  
Vol 114 (45) ◽  
pp. E9626-E9634 ◽  
Author(s):  
Dietmar Herndler-Brandstetter ◽  
Liang Shan ◽  
Yi Yao ◽  
Carmen Stecher ◽  
Valerie Plajer ◽  
...  
Keyword(s):  
Mouse Model ◽  
Nk Cells ◽  
Natural Killer ◽  
Cancer Biology ◽  
Nk Cell ◽  
T Cell Subsets ◽  
Humanized Mouse ◽  
Humanized Mouse Model ◽  
Hematopoietic Stem

Immunodeficient mice reconstituted with a human immune system represent a promising tool for translational research as they may allow modeling and therapy of human diseases in vivo. However, insufficient development and function of human natural killer (NK) cells and T cell subsets limit the applicability of humanized mice for studying cancer biology and therapy. Here, we describe a human interleukin 15 (IL15) and human signal regulatory protein alpha (SIRPA) knock-in mouse on a Rag2−/− Il2rg−/− background (SRG-15). Transplantation of human hematopoietic stem and progenitor cells into SRG-15 mice dramatically improved the development and functional maturation of circulating and tissue-resident human NK and CD8+ T cells and promoted the development of tissue-resident innate lymphoid cell (ILC) subsets. Profiling of human NK cell subsets by mass cytometry revealed a highly similar expression pattern of killer inhibitory receptors and other candidate molecules in NK cell subpopulations between SRG-15 mice and humans. In contrast to nonobese diabetic severe combined immunodeficient Il2rg−/− (NSG) mice, human NK cells in SRG-15 mice did not require preactivation but infiltrated a Burkitt’s lymphoma xenograft and efficiently inhibited tumor growth following treatment with the therapeutic antibody rituximab. Our humanized mouse model may thus be useful for preclinical testing of novel human NK cell-targeted and combinatory cancer immunotherapies and for studying how they elicit human antitumor immune responses in vivo.

scholarly journals Resistance of Janus Kinase-2 Dependent Leptin Signaling in Natural Killer (NK) Cells: A Novel Mechanism of NK Cell Dysfunction in Diet-Induced Obesity

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3370-3378 ◽  
Author(s):  
Heike Nave ◽  
Guenter Mueller ◽  
Britta Siegmund ◽  
Roland Jacobs ◽  
Thorsten Stroh ◽  
...  
Keyword(s):  
Body Weight ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
The Body ◽  
Janus Kinase ◽  
Mrna Levels ◽  
Rt Pcr ◽  
The Impact

Leptin acts not only as an anorexigenic hormone but also regulates cell-mediated immunity via leptin receptors (Ob-R) expressed on T and B lymphocytes. However, the impact of leptin on natural killer (NK) cells is currently elusive. We evaluated leptin effects on NK cells in relation to the body weight in rats using in vivo and in vitro approaches. Leptin was injected iv in male lean and diet-induced obese Lewis and F344 rats. NK cell numbers were analyzed in blood and spleen by fluorescence activated cell sorting and immunohistochemistry, and the activity of NK cells was measured by chromium release assay. Ob-R expression was investigated by confocal laser scanning and quantitative RT-PCR. To compare leptin-dependent intracellular signaling under basal and leptin- and tumor cell (MADB106)-stimulated conditions, intracellular target proteins of NK cells were evaluated by Western blotting. Number and distribution pattern of splenic NK cells were significantly different in lean and obese animals. Leptin administration resulted in a 4-fold higher stimulation of the NK activity in lean than obese animals. This was not due to a decreased expression of Ob-R because quantitative RT-PCR revealed significantly higher Ob-Rb mRNA levels in NK cells from obese rats. In contrast, postreceptor signaling is differentially abrogated in obese animals with significantly lower activation of postreceptor signaling components (Janus kinase-2p, protein kinase B pT308, AMPαpT172) after an in vivo leptin challenge. In conclusion, the results for the first time assign leptin a central role as a modulator of NK cell number and activity only in lean but not obese subjects. The differential role of leptin has important implications for the influence of body weight in the response to systemic inflammations and in the immunological defense of cancer.

scholarly journals PTEN regulates natural killer cell trafficking in vivo

2015 ◽  
Vol 112 (7) ◽  
pp. E700-E709 ◽  
Author(s):  
Jeffrey W. Leong ◽  
Stephanie E. Schneider ◽  
Ryan P. Sullivan ◽  
Bijal A. Parikh ◽  
Bryan A. Anthony ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Peripheral Blood ◽  
Cell Biology ◽  
Nk Cell ◽  
Killer Cell ◽  
Negative Regulator ◽  
Peripheral Organs

Phosphatase and tensin homolog (PTEN) is a critical negative regulator of the phosphoinositide-3 kinase pathway, members of which play integral roles in natural killer (NK) cell development and function. However, the functions of PTEN in NK cell biology remain unknown. Here, we used an NK cell-specific PTEN-deletion mouse model to define the ramifications of intrinsic NK cell PTEN loss in vivo. In these mice, there was a significant defect in NK cell numbers in the bone marrow and peripheral organs despite increased proliferation and intact peripheral NK cell maturation. Unexpectedly, we observed a significant expansion of peripheral blood NK cells and the premature egress of NK cells from the bone marrow. The altered trafficking of NK cells from peripheral organs into the blood was due to selective hyperresponsiveness to the blood localizing chemokine S1P. To address the importance of this trafficking defect to NK cell immune responses, we investigated the ability of PTEN-deficient NK cells to traffic to a site of tumor challenge. PTEN-deficient NK cells were defective at migrating to distal tumor sites but were more effective at clearing tumors actively introduced into the peripheral blood. Collectively, these data identify PTEN as an essential regulator of NK cell localization in vivo during both homeostasis and malignancy.

Impact of β2 integrin deficiency on mouse natural killer cell development and function

Blood ◽  
2011 ◽  
Vol 117 (10) ◽  
pp. 2874-2882 ◽  
Author(s):  
Karine Crozat ◽  
Céline Eidenschenk ◽  
Baptiste N. Jaeger ◽  
Philippe Krebs ◽  
Sophie Guia ◽  
...  
Keyword(s):  
Cell Surface ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Surface Expression ◽  
Cell Maturation ◽  
Cell Surface Expression ◽  
Mcmv Infection ◽  
Β2 Integrin

Abstract Natural killer (NK) cells are innate immune cells that express members of the leukocyte β2 integrin family in humans and mice. These CD11/CD18 heterodimers play critical roles in leukocyte trafficking, immune synapse formation, and costimulation. The cell-surface expression of one of these integrins, CD11b/CD18, is also recognized as a major marker of mouse NK-cell maturation, but its function on NK cells has been largely ignored. Using N-ethyl-N-nitrosourea (ENU) mutagenesis, we generated a mouse carrying an A → T transverse mutation in the Itgb2 gene, resulting in a mutation that prevented the cell-surface expression of CD18 and its associated CD11a, CD11b, and CD11c proteins. We show that β2 integrin–deficient NK cells have a hyporesponsive phenotype in vitro, and present an alteration of their in vivo developmental program characterized by a selective accumulation of c-kit+ cells. NK-cell missing-self recognition was partially altered in vivo, whereas the early immune response to mouse cytomegalovirus (MCMV) infection occurred normally in CD18-deficient mice. Therefore, β2 integrins are required for optimal NK-cell maturation, but this deficiency is partial and can be bypassed during MCMV infection, highlighting the robustness of antiviral protective responses.

scholarly journals CXCL12-CXCR4 chemokine signaling is essential for NK-cell development in adult mice

Blood ◽  
2011 ◽  
Vol 117 (2) ◽  
pp. 451-458 ◽  
Author(s):  
Mamiko Noda ◽  
Yoshiki Omatsu ◽  
Tatsuki Sugiyama ◽  
Shinya Oishi ◽  
Nobutaka Fujii ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Nk Cell ◽  
Cell Development ◽  
Hematopoietic Stem ◽  
Adult Mice ◽  
Multipotent Progenitors ◽  
Chemokine Signaling ◽  
Chemokine Ligand

Abstract Natural killer (NK) cells are granular lymphocytes that are generated from hematopoietic stem cells and play vital roles in the innate immune response against tumors and viral infection. Generation of NK cells is known to require several cytokines, including interleukin-15 (IL-15) and Fms-like tyrosine kinase 3 ligand, but not IL-2 or IL-7. Here we investigated the in vivo role of CXC chemokine ligand-12 (CXCL12) and its primary receptor CXCR4 in NK-cell development. The numbers of NK cells appeared normal in embryos lacking CXCL12 or CXCR4; however, the numbers of functional NK cells were severely reduced in the bone marrow, spleen, and peripheral blood from adult CXCR4 conditionally deficient mice compared with control animals, probably resulting from cell-intrinsic CXCR4 deficiency. In culture, CXCL12 enhanced the generation of NK cells from lymphoid-primed multipotent progenitors and immature NK cells. In the bone marrow, expression of IL-15 mRNA was considerably higher in CXCL12-abundant reticular (CAR) cells than in other marrow cells, and most NK cells were in contact with the processes of CAR cells. Thus, CXCL12-CXCR4 chemokine signaling is essential for NK-cell development in adults, and CAR cells might function as a niche for NK cells in bone marrow.

scholarly journals Production of colony-stimulating activity by human natural killer cells: analysis of the conditions that influence the release and detection of colony-stimulating activity

Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 156-164
Author(s):  
V Pistoia ◽  
S Zupo ◽  
A Corcione ◽  
S Roncella ◽  
L Matera ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Nk Cells ◽  
Natural Killer ◽  
Peripheral Blood ◽  
Nk Cell ◽  
K562 Cells ◽  
Cell Suspensions ◽  
Normal Peripheral Blood ◽  
Colony Stimulating Activity ◽  
Culture Supernatants

Highly purified natural killer (NK) cell suspensions were tested for their capacity to release colony-stimulating activity (CSA) in vitro. NK cell suspensions comprised primarily CD16+ cells and were devoid of CD3+ T cells, CD15+ monocytes, and of B cells. CSA was detected in the NK cell supernatants and sustained the growth of myeloid colonies from both normal peripheral blood and bone marrow. CSA could be in part inhibited by pretreating NK cell culture supernatants with a specific goat anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antiserum. The inhibition, however, was never complete, a finding that suggests that additional factors were responsible for CSA. Incubation of NK cells with K562 cells (an NK-sensitive target) or with normal bone marrow cells resulted in the appearance of a strong colony- inhibiting activity (CIA) in the culture supernatants. Such CIA was demonstrable in an experimental system where bone marrow or peripheral blood progenitors were induced to form myeloid colonies in the presence of conditioned medium by CSA-producing giant cell tumor (GCT) cells. Stimulation of NK cells with NK-insensitive targets failed to induce CIA production. Neutralizing antitumor necrosis factor (TNF) monoclonal antibodies (MoAbs) were found capable of inhibiting CIA present in the supernatants of NK cells stimulated with K562 cells. Following treatment with anti-TNF antibodies, CSA was again detectable in the same supernatants. This finding indicates that induction of TNF production did not concomitantly switch off CSA production by NK cells. Pretreatment of NK cells with recombinant interleukin-2 (rIL-2) or gamma interferon (r gamma IFN) did not change the amount of CSA released. However, treatment with rIL-2 caused the appearance of a factor in the NK cell supernatants capable of sustaining the formation of colonies of a larger size.

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