مجال التميز

تميز دراسي وبحثي (ماجستير ودكتواره)

البحوث المنشورة

البحث (1):

عنوان البحث:

The unique profile of cord blood natural killer cells balances incomplete maturation and effective killing function upon activation

رابط البحث:

تاريخ النشر:

March 2012

موجز عن البحث:

Cord blood (CB) is increasingly used as a source of stem cells for hematopoietic stem cell transplantation, and natural killer (NK) cells may be the effectors of the antileukemic response observed after CB transplantation. Here, we analyzed the phenotype and functions of CB NK cell subsets. We determined that the percentage of NK cells was higher in CB compared with peripheral blood (PB). Furthermore, there was a higher percentage of the CD56(bright) subset in CB. CB NK cells reached a late stage of differentiation, but exhibited higher expression of NKG2A and expressed fewer killer-cell immunoglobulin-like receptors, suggesting an incomplete maturation. CB NK cells highly expressed CXCR4, but did not express L-selectin, highlighting unique homing properties of CB NK cells. CB NK cells proliferated in response to interleukin-2 and degranulated in response to stimulation with tumor cells, but failed to lyse K562 cells in (51)Cr-release assay. CB NK cells exhibited a lower interferon-γ production in comparison with PB NK cells. Culture with IL-2 increased CB NK cell functions. Our study sheds light on CB NK cell properties and highlights the potential of CB as a source of NK cells for immunotherapy.

المؤتمرات العلمية:

المؤتمر (1):

عنوان المؤتمر:

Fourth Annual Scientific Forum – Research Day

تاريخ الإنعقاد:

12^th & 13^th November 2013

بلد ومكان الإنعقاد:

KSA

طبيعة المشاركة:

Oral Presentation

ملخص المشاركة:

Cord blood (CB) has recently been used as an alternative source of haematopoietic stem cells (HSCs) for transplantation, as it has clinical advantages over other sources of HSCs including: off the shelf availability, less stringent human leucocyte antigen matching, reduced incidence and severity of graft-versus-host disease (GvHD), and preservation of the graft- versus -leukaemia (GvL) effect. Natural Killer (NK) cells are prominent in CB constituting up to 30% of the total mononuclear cells, and their reconstitution occurs early after transplantation. Hence, NK cells are key effectors in mediating the GvL effect in CB transplantation settings. In this study we aimed to investigate whether CB NK cells can be activated by cytokines and become fully functional as for peripheral blood NK cells. Cytokines involved in stimulation and proliferation of NK cells were used including Interleukin (IL)-2, IL-12, IL-15, IL-18, the combination of IL-15 and IL-18 or the combination of IL-15 and IL-2. We studied both the phenotypic characteristics and functional capabilities of cytokine-activated CB NK cells. A thorough investigation and comparative study to peripheral blood NK cells was carried out in each experiment. We investigated expression of cytokine receptor, the phenotype of activated CB NK cells, capability of NK cells to proliferate in the presence of cytokines, signalling pathway for IL-2 and IL-12, IFN-g and TNF-a production, and killing capacity. Our results indicated that CB NK cells are readily responsive to cytokine treatment presenting a comparative amount of cytokines’ receptors. However, CB NK cells express significantly less receptors of IL-2 explaining less activation acquired by IL-2. CB NK cells acquire the phenotype of activated NK cells upon activation with cytokines showing up-regulation of activation markers, adhesion molecules, and secondary lymphoid tissues homing repertoire. Testing CB NK cell cultures’ supernatants revealed high production of IFN-g but not TNF-a. Nonetheless, differential findings depending on which cytokine used was observed. CB NK cells gain the tendency to proliferate in the presence of cytokines diluting the CFSE fluorescence by day 2. Interestingly, better proliferation was observed in cultures containing a combination of IL-15 and IL-18. Cytokines’ treated CB NK cells when co-cultured with K562 were able to kill this cell line in 51Cr release cytotoxicity assay. All together, this study aims to identify which cytokine or a combination of cytokines promotes fully functional CB NK cells that could be used for therapeutic purposes.

المؤتمر (2):

عنوان المؤتمر:

14^th Meeting of the Society for Natural Immunity

تاريخ الإنعقاد:

18^th to 22^nd September 2013

بلد ومكان الإنعقاد:

Heidelberg, Germany

طبيعة المشاركة:

Poster Presentation

ملخص المشاركة:

Natural killer (NK) cells play substantial role in clearing infected cells and tumour cells, and in mediating graft versus leukaemia effect (GvL) in transplantation settings. In this study, we aimed to investigate the mechanisms of cord blood (CB) NK cell activation and compare it to peripheral blood (PB) NK cells to identify which conditions lead to fully activated functional NK cells for immunotherapy. Cytokines involved in stimulation and proliferation of NK cells were used including Interleukin (IL)-2, IL-12, IL-15, IL-18, thecombination of IL-15 and IL-18 or the combination of IL-15 and IL-2. We studied both the phenotypic characteristics and functional capabilities of cytokine-activated NK cells. Our results indicated that CB NK cells are readily responsive to cytokine treatment presenting a comparative amount of most cytokines’ receptors. However, CB NK cells express significantly less IL-2 receptors correlating with the lower levels of activation reached after IL-2 stimulation. CB NK cells acquire the phenotype of activated NK cells upon ctivation with cytokines showing up-regulation of activation markers, adhesion molecules, and secondary lymphoid tissues homing markers. The analysis of CB NK cell cultures’ supernatants revealed high production of IFN-g and inflammatory cytokines (IL-6, IL-8) but only traces of TNF-a. Nonetheless, differential findings depending on which cytokine used was observed. CB NK cells gained the tendency to proliferate in the presence of cytokines diluting CFSE by day 2. Interestingly, better proliferation was observed in cultures containing a combination of IL-15 and IL-18. Cytokines’ treated CB NK cells when co-cultured with K562 were able to kill this cell line in 51Cr release cytotoxicity assay. Our early finding of relative gene expression revealed significant differences in FN-g, Granzyme-B, Perforin, and BCL-2 expression based on the cytokine condition used. Our results from transwell migration assay revealed that CB NK cells when treated with the combination of IL-15 and IL-2 or IL-15 and IL-18 were able to migrate toward CCL19/21 and CXCL10/11 chemokine signal showing similar pattern of migration to PB NK cells. Using cytokines, it was also feasible to induce memory NK cells from CB NK cells that exhibited sustained ability to produce IFN-g at day 21. All together, this study aims to identify which cytokine or combination of cytokines promotes fully functional CB NK cells that could be used for therapeutic purposes.