cytotoxicity

NKp46/NCR1 Protein, Mouse, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 28.6 kDa and the accession number is A0A0R4IZY7.

B7-H6 Protein, Cynomolgus, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with His and Avi tag. The predicted molecular weight is 29.76 kDa and the accession number is XP_005578557.1.

NKp30/NCR3 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 14.4 kDa and the accession number is O14931-1.

NKp30/NCR3 Protein, Cynomolgus, Rhesus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 14.3 kDa and the accession number is XP_005553604.1.

Natural Cytotoxicity Triggering Receptor 3 (NCR3) along with NKp44 and NKp46 constitute a group of receptors termed “Natural Cytotoxicity Receptors”. They play a major role in triggering NK-mediated killing of most tumor cells lines. NKp30 is a type I transmembrane protein having a single extracellular V-like immunoglobulin domain. NKp30 is selectively expressed both in resting and activated human NK cells. In addition, NKp30 is also involved in NK-mediated induction of dendritic cell (DC) maturation. It has been demonstrated that NK cell activation signaling specifically induces lytic activity against several tumor cell types and synthesis of new NF-κB dependent proteins during the initiation of cytotoxicity.

Natural cytotoxicity triggering receptor 1(NCR1) is a single-pass type I membrane protein .It contains 2 Ig-like (immunoglobulin-like) domains and belongs to the natural cytotoxicity receptor (NCR) family. The protein is a natural killer (NK) lymphocyte-activating receptor. It is involved in major aspects of NK immune function and shows a high degree of lineage specificity in blood and bone marrow.

B7-H6 Protein, Rat, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 60.4 kDa and the accession number is XP_006223356.1.

NKp44/NCR2 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 20 kDa and the accession number is O95944-1.

NKp30/NCR3 Protein, Human, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 39.6 kDa and the accession number is O14931-3.

NKp46/NCR1 Protein, Rat, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 54.1 kDa and the accession number is Q9Z0H5.

NKp44/NCR2 Protein, Human, Recombinant (His), Biotinylated is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 20 kDa and the accession number is O95944-1.

B7-H6 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 28.1 kDa and the accession number is Q68D85.

NKp30/NCR3 Protein, Rat, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 15.2 kDa and the accession number is CAD23066.1.

B7-H6 Protein, Rat, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 35.1 kDa and the accession number is XP_006223356.1.

B7-H6 Protein, Cynomolgus, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 53.2 kDa and the accession number is XP_005578557.1.

B7-H6 Protein, Cynomolgus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 27.9 kDa and the accession number is XP_005578557.1.

B7-H6 Protein, Human, Recombinant (His), Biotinylated is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 28.1 kDa and the accession number is Q68D85.

B7-H6 Protein, Human, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 53.4 kDa and the accession number is Q68D85.

G protein-coupled receptor kinase 6, also known as G protein-coupled receptor kinase GRK6, GRK6, and GPRK6, is a lipid-anchor protein that belongs to the protein kinase superfamily, AGC Ser/Thr protein kinase family, and GPRK subfamily. GRK6 / GPRK6 contains one AGC-kinase C-terminal domain, one protein kinase domain, and one RGS domain. This protein phosphorylates the activated forms of G protein-coupled receptors thus initiating their deactivation. Several transcript variants encoding different isoforms have been described. GRK6 / GPRK6 is widely expressed. GRK6 / GPRK6 silencing causes suppression of signal transducer and activator of transcription 3 (STAT3) phosphorylation associated with a reduction in MCL1 levels and phosphorylation, illustrating a potent mechanism for the cytotoxicity of GRK6 inhibition in multiple myeloma (MM) tumor cells. GRK6 also appears to be involved in responses to morphine. Inhibition of GRK6 represents a uniquely targeted novel therapeutic strategy in human multiple myeloma.

SLAM Family Member 6 (SLAMF6) is a 60 kD single-pass type I membrane protein that belongs to the SLAM subgroup of the CD2 family. Human SLAMF6/ NTB-A contains a 205 amino acid extracellular domain (ECD) with one Ig-like V-set and one Ig-like C2-set domain, a 21 amino acid transmembrane segment and an 84 amino acid cytoplasmic domain, with two immunoreceptor tyrosine-based switch motifs. SLAMF6 is a homodimer. SLAMF6 can interact with PTN6 and, upon phosphorylation, with PTN11 and SH2D1A/SAP. Phosphorylation-dependent NTB-A association with SAP is required for full production of IFN-γ by NK cells and independent of EAT-2 binding. It Triggers cytolytic activity only in natural killer cells (NK) expressing high surface densities of natural cytotoxicity receptors. On B cells, NTB-A modulates immunoglobulin class switching and the balance between tolerance and autoimmunity.

NKp30, along with NKp44 and NKp46, constitute a group of receptors termed Natural Cytotoxicity Receptors . These receptors play a major role in triggering NK-mediated killing of most tumor cells lines.NKp30 stimulates NK cells cytotoxicity toward neighboring cells producing these ligands. It controls, for instance, NK cells cytotoxicity against tumor cells.

Guanine nucleotide exchange factor (GEF) which specifically activates small GTPase CDC42 by exchanging bound GDP for free GTP. During immune responses, required for interstitial dendritic cell (DC) migration by locally activating CDC42 at the leading edge membrane of DC. Required for CD4(+) T-cell migration in response to chemokine stimulation by promoting CDC42 activation at T cell leading edge membrane. Is involved in NK cell cytotoxicity controlling polarization of microtubule-organizing center (MTOC), and possibly regulating CCDC88B-mediated lytic granule transport to MTOC during cell killing.

Melanoma antigen recognized by T cell-1 (Mart-1), one of the melanosome-specific proteins, also recognized by cytotoxicity T lymphocytes as a marker. Mart-1 is considered to play a critical role in the immunotherapy for melanoma.

Nutlin-3 variably induces apoptosis and cell cycle arrest in cancer cells while it shows low/absent cytotoxicity in normal cells, Nutlin-3 is a promising anti-cancer agent, which exhibits activity against a variety of cancers, including acute myeloid leukemia (AML). The important role of TP53I3/PIG3 in mediating the apoptotic activity of Nutlin-3 was underlined by knock-down experiments with siRNA specific for TP53I3/PIG3, which resulted in a significant decrease in the pro-apoptotic activity of Nutlin-3.

NKp80, also known as KLRF1, is an activating homodimeric C-type lectin-like receptor that is expressed on nearly all-natural killer cells and stimulates their cytotoxicity and cytokine release. NKp80 stimulates cytotoxicity upon engagement of its genetically linked ligand: myeloid-specific CTLR activation-induced C-type lectin (AICL). NKp80, but not NKp80 mutated at tyrosine 7 (NKp80/Y7F), is tyrosine phosphorylated. Accordingly, NKp80/Y7F, but not NKp80/Y3F or NKp80/Y37F, failed to induce cytotoxicity. NKp80 phosphopeptides comprising the Hemi-ITAM-like sequence surrounding tyrosine 7 bound Lck- and Syk-family kinases; accordingly, cross-linking of NKp8, but not NKp80/Y7F, induced Syk phosphorylation. Moreover, inhibition of Syk kinase, but not ZAP-7 kinase, impaired cytotoxic responses through NKp80. Atypical residues in the Hemi-ITAM-like motif of NKp80 cause an altered stoichiometry of phosphorylation but did not substantially affect NK cytotoxicity. Altogether, these results show that NKp80 uses an atypical Hemi-ITAM and Syk kinase to trigger cellular cytotoxicity.

B7 Homolog 4 (B7-H4) is glycosylated member of the B7 family of immune costimulatory proteins. Mature human B7-H4 consists of a 235 amino acid (aa) extracellular domain (ECD) with two Ig-like V-type domains, a 21 aa transmembrane segment, and a 2 aa cytoplasmic tail. It is widely expressed, including in kidney, liver, lung, pancreas, placenta, prostate, spleen, testis and thymus. B7-H4 negatively regulates T-cell-mediated immune response by inhibiting T-cell activation, proliferation, cytokine production and development of cytotoxicity. When expressed on the cell surface of tumor macrophages, plays an important role, together with regulatory T-cells (Treg), in the suppression of tumor-associated antigen-specific T-cell immunity. It also involved in promoting epithelial cell transformation.

As a monomeric immunoglobulin that is predominately involved in the secondary antibody response and the only isotype that can pass through the human placenta, Immunoglobulin G (IgG) is synthesized and secreted by plasma B cells, and constitutes 75% of serum immunoglobulins in humans. IgG antibodies protect the body against the pathogens by agglutination and immobilization, complement activation, toxin neutralization, as well as the antibody-dependent cell-mediated cytotoxicity (ADCC). IgG tetramer contains two heavy chains (50 kDa ) and two light chains (25 kDa) linked by disulfide bonds, that is the two identical halves form the Y-like shape. IgG is digested by pepsin proteolysis into Fab fragment (antigen-binding fragment) and Fc fragment ( crystallizable fragment). IgG1 is most abundant in serum among the four IgG subclasses (IgG1, 2, 3 and 4) and binds to Fc receptors (FcγR ) on phagocytic cells with high affinity. Fc fragment is demonstrated to mediate phagocytosis, trigger inflammation, and target Ig to particular tissues. Protein G or Protein A on the surface of certain Staphylococcal and Streptococcal strains specifically binds with the Fc region of IgGs, and has numerous applications in biotechnology as a reagent for affinity purification. Recombinant IgG Fc Region is suggested to represent a potential anti-inflammatory drug for treatment of human autoimmune diseases.

Low affinity immunoglobulin gamma Fc region receptor III (Fc gamma RIII/CD16) is a member of the Ig superfamily. Based on close relationships in their extracellular domains, the Fc gamma Rs have been divided into three classes composing of Fc gamma RI (CD64), Fc gamma RII (CD32), and Fc gamma RIII (CD16). Each group may be encoded by multiple genes and exist in different isoforms depending on species and cell type. Mouse CD16 is a type I transmembrane protein having two extracellular Ig-like domains consisting of immunoglobulin domain, repeat, signa and transmembrane, transmembrane helix. It is expressed on a variety of myeloid and lymphoid cells and associates with Fc R gamma to deliver an activating signal upon ligand binding. Fcgr3 is IgG binding and activation or inhibition of immune responses such as antibody-dependent cellular cytotoxicity, phagocytosis, cell surface receptor signaling pathway and positive regulation of type I/IIa/III hypersensitivity.

2B4 (CD244) is expressed by memory-phenotype CD8() T cells and all natural killer (NK) cells. The ligand for 2B4, CD48, is expressed on hematopoietic cells. 2B4 is conserved in humans and mice, and a number of reports have linked 2B4 with activation of lymphocytes.Engagement of 2B4 on NK cell surfaces with specific antibodies or CD48 can trigger cell mediated cytotoxicity, interferon γ secretion, phosphoinositol turnover and NK cell invasiveness.

ULBPs activate multiple signaling pathways in primary NK cells, resulting in the production of cytokines and chemokines. Binding of ULBPs ligands to NKG2D induces calcium mobilization and activation of the JAK2, STAT5, ERK and PI3K kinase/Akt signal transduction pathway, mediating natural killer cell cytotoxicity.

NKp46, along with NKp30 and NKp44, are activating receptors that have been collectively termed the natural cytotoxicity receptors (NCR).These receptors lack significant sequence homology to one another. They are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. NKp46/NCR1 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with N-His tag. The predicted molecular weight is 27.5 kDa and the accession number is O76036-6.

NKp46, along with NKp30 and NKp44, are activating receptors that have been collectively termed the natural cytotoxicity receptors (NCR).These receptors lack significant sequence homology to one another. They are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. NKp46/NCR1 Protein (Primary Amine Labeling), Human, Recombinant (His), Biotinylated is expressed in HEK293 mammalian cells with N-His tag. The predicted molecular weight is 27.5 kDa and the accession number is O76036-6.

Human Fc gamma RIIIA/CD16a Protein is a receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. Fc gamma RIIIA/CD16a (F176) Protein, Human, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 24.7 kDa and the accession number is P08637-1.

NKp46, along with NKp30 and NKp44, are activating receptors that have been collectively termed the natural cytotoxicity receptors (NCR).These receptors lack significant sequence homology to one another. They are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. NKp46/NCR1 Protein, Human, Recombinant (hFc) is expressed in HEK293 mammalian cells with C-hFc tag. The predicted molecular weight is 53.2 kDa and the accession number is O76036-1.

NKp46, along with NKp30 and NKp44, are activating receptors that have been collectively termed the natural cytotoxicity receptors (NCR).These receptors lack significant sequence homology to one another. They are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. NKp46/NCR1 Protein, Cynomolgus, Recombinant (hFc) is expressed in HEK293 mammalian cells with C-hFc tag. The predicted molecular weight is 53.1 kDa and the accession number is Q95JB9.

Class-I Restricted T Cell-Associated Molecule (CRTAM) is a protein that is expressed after T cell activation. The interaction of CRTAM with its ligand, nectin-like 2 (Necl2), is required for the efficient production of IL-17, IL-22, and IFNγ by murine CD4 T cells, and it plays a role in optimal CD8 T and NK cell cytotoxicity. CRTAM promotes the pro-inflammatory cytokine profile; therefore, it may take part in the immunopathology of autoimmune diseases such as diabetes type 1 or colitis. CRTAM Protein, Canine, Recombinant (His) is expressed in HEK293 mammalian cells with C-His tag. The predicted molecular weight is 31.19 kDa and the accession number is E2QWY2.

Associates with chromatin regions downstream of transcriptional start sites of active genes and thus regulates gene transcription. Chromatin interaction is mediated via the binding to tri-methylated histone H3 at 'Lys-4' (H3K4me3). Key regulator of hematopoiesis involved in terminal myeloid differentiation and in the regulation of hematopoietic stem cell (HSCs) self-renewal by a mechanism that involves DNA methylation. Also acts as an important cell cycle regulator, participating in cell cycle regulatory network machinery at multiple cell cycle stages including G1/S transition, S phase progression and mitotic entry. Recruited to E2F1 responsive promoters by HCFC1 where it stimulates tri-methylation of histone H3 at 'Lys-4' and transcriptional activation and thereby facilitates G1 to S phase transition. During myoblast differentiation, required to suppress inappropriate expression of S-phase-promoting genes and maintain expression of determination genes in quiescent cells.; Cellular ligand for NCR2/NKp44, may play a role as a danger signal in cytotoxicity and NK-cell-mediated innate immunity.

CD112 is a type I transmembrane glycoprotein belonging to the Immunoglobulin superfamily. It comprises one Ig-like V-type domain and two Ig-like C2-type domains in the extracellular region. The V domain is believed to mediate nectin binding to its ligands. Nectin2 is known to bind the pseudorabies virus, and herpes simplex virus2 (HSV2), involving in cell to cell spreading of these viruses. It does not bind poliovirus. As a homophilic adhesion molecule, CD112 is found concentrated in adherens junctions, and exists on neurons, endothelial cells,epithelial cells and fibroblasts. CD112 has been identified as the ligand for DNAM-1 (CD226), and the interaction of CD226/CD112 mediates cytotoxicity and cytokine secretion by T and NK cells. The costimulatory responses may be a critical component in allergic reactions and may therefore become targets for anti-allergic therapy.

Natural cytotoxicity triggering receptor 1(NKp46/NCR1) is a single-pass type I membrane protein. It consists of two extracellular Ig-like domains followed by a short stalk region, a transmembrane domain containing a positively charged amino acid residue, and a short cytoplasmictail. NKp46 is predominantly expressed in the embryo. It has a positive charge in its transmembrane domain that permits association with the ITAM-bearing signal adapter proteins, CD3 zeta and Fc epsilon RI gamma. These receptors are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. Studies with neutralizing antibodies indicate that the three NCR are primarily responsible for triggering the NK-mediated lysis of many human tumor celllines.

Cell adhesion molecule 1(CADM1) is a single-pass type I membrane protein and belongs to the nectin family. It contains 2 Ig-like C2-type (immunoglobulin-like) domains and 1 Ig-like V-type (immunoglobulin-like) domain. CADM1 acts as a tumor suppressor in non-small-cell lung cancer (NSCLC) cells. Interaction with CRTAM promotes natural killer (NK) cell cytotoxicity and interferon-gamma (IFN-gamma) secretion by CD8+ cells in vitro as well as NK cell-mediated rejection of tumors expressing CADM3 in vivo. CADM1 may contribute to the less invasive phenotypes of lepidic growth tumor cells. In mast cells, it may mediate attachment to and promote communication with nerves. CADM1, together with MITF, is essential for development and survival of mast cells in vivo. The protein acts as a synaptic cell adhesion molecule and plays a role in the formation of dendritic spines and in synapse assembly. It may be involved in neuronal migration, axon growth, pathfinding, and fasciculation on the axons of differentiating neurons. CADM1 may play diverse roles in the spermatogenesis including in the adhesion of spermatocytes and spermatids to Sertoli cells and for their normal differentiation into mature spermatozoa.

Human Fc gamma RIIIA/CD16a Protein is a receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. Fc gamma RIIIA/CD16a (V176) Protein, Human, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 24.7 kDa and the accession number is AAH17865.

The Human Fc gamma RIIIA/CD16a Protein is a receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis.

Human Fc gamma RIIIA/CD16a Protein is a receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. Fc gamma RIIIA/CD16a (F176) Protein, Human, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 24.7 kDa and the accession number is P08637-1.

NKp46, along with NKp30 and NKp44, are activating receptors that have been collectively termed the natural cytotoxicity receptors (NCR).These receptors lack significant sequence homology to one another. They are expressed almost exclusively by NK cells and play a major role in triggering some of the key lytic activities of NK cells. NKp46/NCR1 Protein, Human, Recombinant (mFc) is expressed in HEK293 mammalian cells with C-mFc tag. The predicted molecular weight is 52.9 kDa and the accession number is O76036-1.

Basic protein that binds to cell membrane and depolarizes cardiomyocytes. It also shows lytic activities, but 2-fold less important than that of CTX-A4. It binds to the integrin alpha-V/beta-3 (ITGAV/ITGB3) with a moderate affinity. It may interact with sulfatides in the cell membrane which induces pore formation and cell internalization and is responsible for cytotoxicity in cardiomyocytes. It also may target the mitochondrial membrane and induce mitochondrial swelling and fragmentation.

SerpinB9, also known as Cytoplasmic antiproteinase 3, CAP-3, Peptidase inhibitor 9, SERPINB9 and PI-9, is a cytoplasm protein that belongs to the serpin family and Ov-serpin subfamily. Serpin-B9 ( CAP-3 / PI-9 ) is the only known human intracellular inhibitor of granzyme B (GrB), the effector molecule in immunity against cytomegalovirus (CMV) and in renal allograft rejection. Serpin-B9 and SPI-6 expression in immune-privileged cells, APCs, and CTLs protect these cells against the actions of granzyme B, and when expressed in tumor cells or virally infected hepatocytes, confers resistance to killing by CTL and NK cells. Expression of increasing levels of Serpin-B9 ( CAP-3 / PI-9 ) in target cells may progressively inhibit immune surveillance by blocking NK and CTL-induced cytotoxicity through the perforin / granzyme pathway and then through the Fas / FasL pathway. Serpin-B9 ( CAP-3 / PI-9 ) is selectively up-regulated in hepatocytes in response to infiltration of the liver by NK cells that express perforin and enzymatically active granzyme B. Upregulated expression of Serpin-B9 ( CAP-3 / PI-9 ) in NSCLC cells may serve to protect them from apoptosis induced by GrB.

HCST (Hematopoietic Cell Signal Transducer, also known as DAP1) is a Protein Coding gene. HCST belongs to the DAP10 family. It is a transmembrane signaling adaptor that contains a YxxM motif in its cytoplasmic domain. The encoded protein may form part of the immune recognition receptor complex with the C-type lectin-like receptor NKG2D. HCST may be part of the immune recognition receptor complex. This receptor plays a major role in triggering cytotoxicity against target cells expressing cell surface ligands such as MHC class I chain-related MICA and MICB, and UL16-binding proteins (ULBPs). It may activate phosphatidylinositol 3-kinase dependent signaling pathways through its intracytoplasmic YxxM motif.

B7 Homolog 4 (B7-H4) is glycosylated member of the B7 family of immune costimulatory proteins.It is widely expressed, including in kidney, liver, lung, pancreas, placenta, prostate, spleen, testis and thymus. B7-H4 negatively regulates T-cell-mediated immune response by inhibiting T-cell activation, proliferation, cytokine production and development of cytotoxicity. When expressed on the cell surface of tumor macrophages, plays an important role, together with regulatory T-cells (Treg), in the suppression of tumor-associated antigen-specific T-cell immunity. It also involved in promoting epithelial cell transformation.

As a monomeric immunoglobulin that is predominately involved in the secondary antibody response and the only isotype that can pass through the human placenta, Immunoglobulin G (IgG) is synthesized and secreted by plasma B cells. IgG antibodies protect the body against the pathogens by agglutination and immobilization, complement activation, toxin neutralization, as well as the antibody-dependent cell-mediated cytotoxicity (ADCC). IgG tetramer contains two heavy chains (50 kDa ) and two light chains (25 kDa) linked by disulfide bonds, that is the two identical halves form the Y-like shape. IgG is digested by pepsin proteolysis into Fab fragment (antigen-binding fragment) and Fc fragment ( crystallizable fragment). IgG1 is most abundant in serum among the four IgG subclasses (IgG1, 2, 3 and 4) and binds to Fc receptors (FcγR ) on phagocytic cells with high affinity.

Killer cell immunoglobulin-like receptor 2DL4(KIR2DL4) is a Single-pass type I membrane protein and contains 2 Ig-like C2-type (immunoglobulin-like) domains.It belongs to the immunoglobulin superfamily. KIR2DL4 is expressed in all NK cells and some T cells. KIR2DL4 activates the cytotoxicity of NK cells, despite the presence of an immunoreceptor tyrosine-based inhibition motif (ITIM) in its cytoplasmic tail. The ITIM was not necessary for activation of lysis by KIR2DL4. The activation signal of KIR2DL4 was sensitive to inhibition by another ITIM-containing receptor. The activation-deficient mutant of KIR2DL4 inhibited the signal delivered by the activating receptor CD16.