Browsing by Author "Mirjačić Martinović, Katarina (16203278500)"

Aim As innate immune cells natural killer (NK), NK-like T and CTLγδ are important in antitumour response in multiple myeloma (MM), the aim of this study was to investigate some functional and phenotypical characteristics of these cells in MM. Methods 29 patients with MM prior to therapy, in clinical stage I-III and 15 healthy controls (HCs) were investigated. Percent of immune cells in peripheral blood, NK cell activity, expression of activating (CD161) and inhibitory (CD158a, CD158b) NK cell receptors on CD3 - CD16 + NK cells were evaluated using 51-chromium-release assay and by flow cytometry. Production of interleukin (IL) 2 and tumour necrosis factor (TNF)α was analysed in supernatants from in vitro activated peripheral blood mononuclear cells. Results In patients with MM the percent of NK cells and their two subsets did not differ from controls, while NK-like T and CTLγδ cells were significantly decreased. Significant impairment of NK cell cytotoxicity, CD107a expression and interferon γ intracellular level was also shown. There was a significant decrease in CD161 and an increase in CD158a receptor expression on NK cells in these patients. Also IL-2 production was lowest in clinical stage III. However, TNF-α production did not differ between patients and HCs. Conclusions Altered expression of CD161 activating and CD158a KIR inhibitory receptor is responsible for impaired antitumour activity of NK cells in MM patients. These new biomarkers may be helpful for patient selection for immunotherapy with cytokines, and novel KIR blocking monoclonal antibodies that enhance NK cell antimyeloma activity and provide clinical benefit. © Published by the BMJ Publishing Group Limited.

In metastatic melanoma (MM) immunomodulating agents, such as interleukin-2 (IL-2) and interferon-α (IFN-α), have shown therapeutic benefit as they enhance antitumor immune response. Considering tumor-induced suppression of natural killer (NK) cell activity, it is of interest to study the affect of these cytokines on the functional and receptor characteristics of CD16-defined NK cells and their dim and bright subsets. Peripheral blood lymphocytes of MM patients in clinical stage IV were treated in vitro for 18h with IFN-α (250U/ml) and rhIL-2 (200U/ml) at 37°C. Both the cytokines induced significant in-vitro enhancement of NK cell activity. NKG2D receptor was induced by IL-2, whereas both the NKG2D and CD161 receptor expression was induced by IFN-α on NK cells and CD16bright NK cell subset. However, only IL-2 mediated induction of NKG2D on CD3-CD16 NK cells correlates with enhanced NK cytotoxicity by this cytokine, whereas, on the cytotoxic CD16 subset NKG2D induction by both cytokines correlates with their induction of NK cell activity. In contrast, the observed induction of these receptors on the regulatory CD16 subset shows no correlation with the obtained augmentation of cytotoxicity. We found substantial specific inducibility of pSTAT1 and pSTAT5, as well as induction of interferon-regulatory transcription factor-1 transcription by investigated cytokines in peripheral blood lymphocytes of MM patients. As NK cell-mediated killing of tumor cells depends on the balance between stimulatory and inhibitory signaling, induction of activating NKG2D receptor by IL-2 and IFN-α, especially in CD16 NK cell subset, gives insight to novel aspects of NK cell activation by these cytokines that are applied in immunotherapy. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

In metastatic melanoma (MM) immunomodulating agents, such as interleukin-2 (IL-2) and interferon-α (IFN-α), have shown therapeutic benefit as they enhance antitumor immune response. Considering tumor-induced suppression of natural killer (NK) cell activity, it is of interest to study the affect of these cytokines on the functional and receptor characteristics of CD16-defined NK cells and their dim and bright subsets. Peripheral blood lymphocytes of MM patients in clinical stage IV were treated in vitro for 18h with IFN-α (250U/ml) and rhIL-2 (200U/ml) at 37°C. Both the cytokines induced significant in-vitro enhancement of NK cell activity. NKG2D receptor was induced by IL-2, whereas both the NKG2D and CD161 receptor expression was induced by IFN-α on NK cells and CD16bright NK cell subset. However, only IL-2 mediated induction of NKG2D on CD3-CD16 NK cells correlates with enhanced NK cytotoxicity by this cytokine, whereas, on the cytotoxic CD16 subset NKG2D induction by both cytokines correlates with their induction of NK cell activity. In contrast, the observed induction of these receptors on the regulatory CD16 subset shows no correlation with the obtained augmentation of cytotoxicity. We found substantial specific inducibility of pSTAT1 and pSTAT5, as well as induction of interferon-regulatory transcription factor-1 transcription by investigated cytokines in peripheral blood lymphocytes of MM patients. As NK cell-mediated killing of tumor cells depends on the balance between stimulatory and inhibitory signaling, induction of activating NKG2D receptor by IL-2 and IFN-α, especially in CD16 NK cell subset, gives insight to novel aspects of NK cell activation by these cytokines that are applied in immunotherapy. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Natural killer (NK) cells play a role in the innate and adaptive antitumor immune responses. The activity of NK cells is regulated by functionally opposing, activating and inhibitory receptors whose balance ultimately determines whether target cells will be susceptible to NK cell mediated lysis. As melanoma is an immunogenic tumor, the effect of immunomodulating agents is consistently investigated. In this study in 79 metastatic melanoma (MM) patients and 52 controls NK activity, expression of activating NKG2D and CD161 receptors and KIR receptors, CD158a and CD158b, on freshly isolated PBL and NK cells were evaluated. Native NK cell activity of melanoma patients in clinical stage I-III and MM patients was determined against NK sensitive K562, NK resistant Daudi, human melanoma FemX, HeLa and HL 60 target tumor cell lines. In addition, predictive pretherapy immunomodulating effect after 18 h in vitro treatments of PBL of MM patients with rh IL-2, IFN-α (IFN), 13-cis retinoic acid (RA) and combination IFN-α and RA was evaluated with respect to NK cell lyses against K562 and FemX cell lines. In this study we show for the first time that low expression of CD161 and activating NKG2D receptors, without increased expression of KIR receptors CD158a and CD158b, as well as a decrease in the cytotoxic, CD16bright NK cell subset, is associated with a significant impairment in NK cell activity in MM patients. Furthermore, the predictive pretherapy finding that IL-2, IFN, IFN and RA, unlike RA alone, can enhance NK cell activity of MM patients against FemX melanoma tumor cell line can be of help in the design and development of therapeutic regimens, considering that it has recently been shown that low-dose combination of different immunomodulators represents the most promising approach in the therapy of MM. © 2007 Springer Science + Business Media B.V.

Natural killer (NK) cells play a role in the innate and adaptive antitumor immune responses. The activity of NK cells is regulated by functionally opposing, activating and inhibitory receptors whose balance ultimately determines whether target cells will be susceptible to NK cell mediated lysis. As melanoma is an immunogenic tumor, the effect of immunomodulating agents is consistently investigated. In this study in 79 metastatic melanoma (MM) patients and 52 controls NK activity, expression of activating NKG2D and CD161 receptors and KIR receptors, CD158a and CD158b, on freshly isolated PBL and NK cells were evaluated. Native NK cell activity of melanoma patients in clinical stage I-III and MM patients was determined against NK sensitive K562, NK resistant Daudi, human melanoma FemX, HeLa and HL 60 target tumor cell lines. In addition, predictive pretherapy immunomodulating effect after 18 h in vitro treatments of PBL of MM patients with rh IL-2, IFN-α (IFN), 13-cis retinoic acid (RA) and combination IFN-α and RA was evaluated with respect to NK cell lyses against K562 and FemX cell lines. In this study we show for the first time that low expression of CD161 and activating NKG2D receptors, without increased expression of KIR receptors CD158a and CD158b, as well as a decrease in the cytotoxic, CD16bright NK cell subset, is associated with a significant impairment in NK cell activity in MM patients. Furthermore, the predictive pretherapy finding that IL-2, IFN, IFN and RA, unlike RA alone, can enhance NK cell activity of MM patients against FemX melanoma tumor cell line can be of help in the design and development of therapeutic regimens, considering that it has recently been shown that low-dose combination of different immunomodulators represents the most promising approach in the therapy of MM. © 2007 Springer Science + Business Media B.V.