The effect of natural killer (NK) cells and lymphokine activated killer ( LAK) cells was studied on a group of human melanoma cell lines. Peripheral blood from healthy volunteers was utilized as a fresh source of natural killer cells and rhI L-2 for producing LAK cells. The cytotoxicity of effector cells was quantified using a 4 hour SI determining the density of antigen expression on tumor...

hematopoietic cord blood (cb) stem cell transplantation has more advantages to other cell sources because of lower graft versus host disease (gvhd). interleukin-15(il-15) is an immunoregulatory cytokine, known to enhance cytolytic function of cord natural killer (nk) cells. the aim of this study was to investigate the effect of il-15 on nk cytotoxicity simultaneously in different cell death sta...

Many chemokine receptors are typically found on natural killer cells, including CX3CR1, the receptor for the chemokine Fractalkine (FKN). This study explored whether interaction between CX3CR1 and FKN is relevant for NK cell functions in cytotoxicity against tumors. FKN expression was examined by polymerase chain reaction and CX3CR1 expression in NK cells was analyzed by flow cytometry. NK cell...

Background: HLA-G is a nonclassical HLA class I molecule which, when elevated in tumor cells, is one of the main factors involved in tumor evasion of immune responses including NK and T cells. Objective: To evaluate the effect of HLA-G downregulation on NK cell cytotoxicity in tumor cell lines. Methods: The expression level of HLA-G was measured by real-time PCR and flowcytometry after transfec...

We have recently shown that Natural Killer (NK) cells control survival and differentiation of Cancer Stem-like Cells (CSCs) through two distinct phenotypes of cytotoxic and anergic NK cells, respectively. In this report, brain CSCs and their serum and NK cell differentiated counterparts were studied. Serum-differentiated brain CSCs were significantly less susceptible to NK cells and CTL direct ...

MHC class I-related chain molecules A and B (MICA and B) expressed on the cell-surface of tumor cells are ligands for an activating receptor, NKG2D, expressed on natural killer (NK) cells and stimulate the NK cell-mediated cytotoxicity. On the other hand, the soluble form of MICA and B produced by proteolytic cleavage of cell-surface MIC interferes with NK cell-mediated cytotoxicity. We investi...

We examined the relationship between natural killer (NK) cell-mediated cytotoxicity, the produced active-oxygen and cytotoxic factor (CF) release in co-culturing canine NK cells with tumor cells (CL-1 target cells). In co-culturing, the adding of n-propyl gallate (active-oxide scavenger) removed the produced active-oxygen, which inhibited NK cell-mediated cytotoxicity and the CF release. Moreov...

the effect of natural killer (nk) cells and lymphokine activated killer ( lak) cells was studied on a group of human melanoma cell lines. peripheral blood from healthy volunteers was utilized as a fresh source of natural killer cells and rhi l-2 for producing lak cells. the cytotoxicity of effector cells was quantified using a 4 hour si determining the density of antigen expression on tumor cel...

The role of different receptors in natural-killer- (NK-) cell-mediated cytotoxicity against multiple myeloma (MM) cells is unknown. We investigated if an enhancement of NK-cell-mediated cytotoxicity against MM could be reached by blocking of the inhibitory leukocyte immunoglobulin-like receptor 1 (LIR-1). Our investigations revealed high levels of LIR-1 expression not only on the NK cell line N...

Perforin (Prf1) and granzyme B (GzmB) are essential effector molecules for natural killer (NK)-cell cytotoxicity, but how Prf1 and GzmB expression is regulated during arming of NK cells is poorly defined. We show that human microRNA (miR)-27a* is a negative regulator of NK-cell cytotoxicity by silencing Prf1 and GzmB expression. Human miR-27a* specifically bound to the 3' untranslated regions o...