In this study, we have used a newly generated monoclonal antibody (mAb C1.7) to identify a novel 38-kD signal-transducing surface molecule (p38) expressed by lymphocyte subsets capable of cell-mediated cytotoxicity. Virtually all CD16+/CD56+ natural killer (NK) cells and approximately half of CD8+ (T cell receptor [TCR] alpha/beta+) T cells and TCR-gamma/delta+ T cells express the p38 surface m...

Natural killer (NK) cells regulate various immune responses by exerting cytotoxic activity or secreting cytokines. The interaction of NK cells with dendritic cells (DC) contributes to NK cell-mediated antitumor or antimicrobial responses. However, the cellular and molecular mechanisms for controlling this interaction are largely unknown. Here, we show an involvement of Jagged2-Notch interaction...

Cellular rejection mechanisms, including NK cells, remain a hurdle for successful pig-to-human xenotransplantation. Human anti-pig NK cytotoxicity depends on the activating receptor NKG2D. Porcine UL16-binding protein 1 (pULBP1) and porcine MHC class I chain-related protein 2 (pMIC2) are homologues of the human NKG2D ligands ULBP 1-4 and MICA and B, respectively. Although transcribed in porcine...

Emerging evidence suggests that NK-activatory receptors use KARAP/DAP12, CD3zeta, and FcepsilonRIgamma adaptors that contain immunoreceptor tyrosine-based activatory motifs to mediate NK direct lysis of tumor cells via Syk tyrosine kinase. NK cells may also use DAP10 to drive natural cytotoxicity through phosphoinositide 3-kinase (PI3K). In contrast to our recently identified PI3K pathway contr...

Natural killer (NK) cells express multiple activating receptors that initiate signaling cascades through DAP10- or immunoreceptor tyrosine-based activation motif-containing adapters, including DAP12 and FcRgamma. Among downstream signaling mediators, the guanine nucleotide exchange factor Vav1 carries out a key role in activation. However, whether Vav1 regulates only some or all NK cell-activat...

NK cell cytotoxicity is controlled by numerous NK inhibitory and activating receptors. Most of the inhibitory receptors bind MHC class I proteins and are expressed in a variegated fashion. It was recently shown that TIGIT, a new protein expressed by T and NK cells binds to PVR and PVR-like receptors and inhibits T cell activity indirectly through the manipulation of DC activity. Here, we show t...

Cytotoxic activity of NK cells was estimated as related to IL-10 and TGF-beta1 serum levels and Helicobacter pylori infection in gastric cancer patients. Moreover, we sought to determine whether human gastric adenocarcinoma cells in vitro release IL-10, TGF-beta1 or factor(s) affecting NK cytotoxicity. The studies were conducted on 42 patients with gastric cancer (14 with I-II stage-group 1; 28...

background: although there is convincing data in support of the effectiveness of hyperthermia in tumor therapy, the molecular mechanisms underlying the clinical effects of hyperthermia are still poorly understood. objective: to investigate natural killer (nk) cell cytotoxicity against heat-treated sw-872 and hela tumor cell lines. methods: nkg2d ligands and hla class i transcription were examin...

Natural killer (NK) cells are considered to be key players in the early innate responses to protozoan infections, primarily indirectly by producing gamma interferon (IFN-gamma) in response to cytokines, like interleukin 12 (IL-12). We demonstrate that live, as well as heat-inactivated, tachyzoites of Neospora caninum, a Toxoplasma-like protozoan, directly trigger production of IFN-gamma from pu...

BACKGROUND AND AIM NK cells are one of the major immune cells in endometriosis pathogenesis. While previous clinical studies have shown that helixor A to be an effective treatment for endometriosis, little is known about its mechanism of action, or its relationship with immune cells. The aim of this study is to investigate the effects of helixor A on Natural killer cell (NK cell) cytotoxicity i...