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Identification and molecular characterization of NKp30, a novel triggering receptor involved in natural cytotoxicity mediated by human natural killer cells.

Pende D, Parolini S, Pessino A, Sivori S, Augugliaro R, Morelli L, Marcenaro E, Accame L, Malaspina A, Biassoni R, Bottino C, Moretta L, Moretta A - J. Exp. Med. (1999)

Bottom Line: This novel receptor is associated with CD3zeta chains that become tyrosine phosphorylated upon sodium pervanadate treatment of NK cells.Molecular cloning of NKp30 cDNA revealed a member of the immunoglobulin superfamily, characterized by a single V-type domain and a charged residue in the transmembrane portion.Moreover, we show that NKp30 is encoded by the previously identified 1C7 gene, for which the function and the cellular distribution of the putative product were not identified in previous studies.

View Article: PubMed Central - PubMed

Affiliation: Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova, Italy.

ABSTRACT
Two major receptors involved in human natural cytotoxicity, NKp46 and NKp44, have recently been identified. However, experimental evidence suggested the existence of additional such receptor(s). In this study, by the generation of monoclonal antibodies (mAbs), we identified NKp30, a novel 30-kD triggering receptor selectively expressed by all resting and activated human natural killer (NK) cells. Although mAb-mediated cross-linking of NKp30 induces strong NK cell activation, mAb-mediated masking inhibits the NK cytotoxicity against normal or tumor target cells. NKp30 cooperates with NKp46 and/or NKp44 in the induction of NK-mediated cytotoxicity against the majority of target cells, whereas it represents the major triggering receptor in the killing of certain tumors. This novel receptor is associated with CD3zeta chains that become tyrosine phosphorylated upon sodium pervanadate treatment of NK cells. Molecular cloning of NKp30 cDNA revealed a member of the immunoglobulin superfamily, characterized by a single V-type domain and a charged residue in the transmembrane portion. Moreover, we show that NKp30 is encoded by the previously identified 1C7 gene, for which the function and the cellular distribution of the putative product were not identified in previous studies.

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Involvement of NKp30 and NKp46 in the tumor cell lysis mediated by NK cell clones. Three NK cell clones were analyzed for cytolytic activity against MEL15, M14, SMMC, and A549 FcγR-negative target cell lines either in the absence (white bars) or presence of AZ20 (anti-NKp30; black bars), BAB281 (anti-NKp46; striped bars) or both AZ20 and BAB281 (stippled bars) mAbs. The E/T ratio was 4:1.
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Figure 5: Involvement of NKp30 and NKp46 in the tumor cell lysis mediated by NK cell clones. Three NK cell clones were analyzed for cytolytic activity against MEL15, M14, SMMC, and A549 FcγR-negative target cell lines either in the absence (white bars) or presence of AZ20 (anti-NKp30; black bars), BAB281 (anti-NKp46; striped bars) or both AZ20 and BAB281 (stippled bars) mAbs. The E/T ratio was 4:1.

Mentions: In view of these data, we further analyzed the effect of mAb-mediated masking of NKp30 on the tumor cell killing by activated NK cells. Fig. 5 shows three representative NK cell clones analyzed in a cytolytic assay against different tumor targets, including two melanomas (MEL15 and M14), a hepatocarcinoma (SMMC), and a lung adenocarcinoma (A549). In previous studies, we showed that the cytolytic activity against the M14 melanoma was confined to NK clones displaying the NKp46bright phenotype and could be inhibited by mAb-mediated masking of NKp46 receptor. On the other hand, NKp46bright clones also killed MEL15. However, neither masking of NKp46 nor of NKp44 significantly inhibited their cytolytic activity 26. These data strongly suggested the existence in these clones of additional triggering receptors responsible for the cytotoxicity against MEL15 target cells. As illustrated above, NKp30 is brightly expressed in NKp46bright clones. Therefore, it is conceivable that it may play a role in the killing of MEL15 target cells. Indeed, as shown in Fig. 5, anti-NKp30 mAb sharply inhibited the NK-mediated lysis of MEL15 cells (>50% of inhibition). Anti-NKp46 mAb exerted a minor effect, whereas an isotype-matched anti-CD56 mAb had no effect (data not shown). On the contrary, lysis of M14 melanoma was inhibited by anti-NKp46 mAb, whereas anti-NKp30 mAb had virtually no effect. Thus, while NKp46 appears as the major receptor involved in lysis of M14, NKp30 plays a central role in the killing of MEL15.


Identification and molecular characterization of NKp30, a novel triggering receptor involved in natural cytotoxicity mediated by human natural killer cells.

Pende D, Parolini S, Pessino A, Sivori S, Augugliaro R, Morelli L, Marcenaro E, Accame L, Malaspina A, Biassoni R, Bottino C, Moretta L, Moretta A - J. Exp. Med. (1999)

Involvement of NKp30 and NKp46 in the tumor cell lysis mediated by NK cell clones. Three NK cell clones were analyzed for cytolytic activity against MEL15, M14, SMMC, and A549 FcγR-negative target cell lines either in the absence (white bars) or presence of AZ20 (anti-NKp30; black bars), BAB281 (anti-NKp46; striped bars) or both AZ20 and BAB281 (stippled bars) mAbs. The E/T ratio was 4:1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195691&req=5

Figure 5: Involvement of NKp30 and NKp46 in the tumor cell lysis mediated by NK cell clones. Three NK cell clones were analyzed for cytolytic activity against MEL15, M14, SMMC, and A549 FcγR-negative target cell lines either in the absence (white bars) or presence of AZ20 (anti-NKp30; black bars), BAB281 (anti-NKp46; striped bars) or both AZ20 and BAB281 (stippled bars) mAbs. The E/T ratio was 4:1.
Mentions: In view of these data, we further analyzed the effect of mAb-mediated masking of NKp30 on the tumor cell killing by activated NK cells. Fig. 5 shows three representative NK cell clones analyzed in a cytolytic assay against different tumor targets, including two melanomas (MEL15 and M14), a hepatocarcinoma (SMMC), and a lung adenocarcinoma (A549). In previous studies, we showed that the cytolytic activity against the M14 melanoma was confined to NK clones displaying the NKp46bright phenotype and could be inhibited by mAb-mediated masking of NKp46 receptor. On the other hand, NKp46bright clones also killed MEL15. However, neither masking of NKp46 nor of NKp44 significantly inhibited their cytolytic activity 26. These data strongly suggested the existence in these clones of additional triggering receptors responsible for the cytotoxicity against MEL15 target cells. As illustrated above, NKp30 is brightly expressed in NKp46bright clones. Therefore, it is conceivable that it may play a role in the killing of MEL15 target cells. Indeed, as shown in Fig. 5, anti-NKp30 mAb sharply inhibited the NK-mediated lysis of MEL15 cells (>50% of inhibition). Anti-NKp46 mAb exerted a minor effect, whereas an isotype-matched anti-CD56 mAb had no effect (data not shown). On the contrary, lysis of M14 melanoma was inhibited by anti-NKp46 mAb, whereas anti-NKp30 mAb had virtually no effect. Thus, while NKp46 appears as the major receptor involved in lysis of M14, NKp30 plays a central role in the killing of MEL15.

Bottom Line: This novel receptor is associated with CD3zeta chains that become tyrosine phosphorylated upon sodium pervanadate treatment of NK cells.Molecular cloning of NKp30 cDNA revealed a member of the immunoglobulin superfamily, characterized by a single V-type domain and a charged residue in the transmembrane portion.Moreover, we show that NKp30 is encoded by the previously identified 1C7 gene, for which the function and the cellular distribution of the putative product were not identified in previous studies.

View Article: PubMed Central - PubMed

Affiliation: Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova, Italy.

ABSTRACT
Two major receptors involved in human natural cytotoxicity, NKp46 and NKp44, have recently been identified. However, experimental evidence suggested the existence of additional such receptor(s). In this study, by the generation of monoclonal antibodies (mAbs), we identified NKp30, a novel 30-kD triggering receptor selectively expressed by all resting and activated human natural killer (NK) cells. Although mAb-mediated cross-linking of NKp30 induces strong NK cell activation, mAb-mediated masking inhibits the NK cytotoxicity against normal or tumor target cells. NKp30 cooperates with NKp46 and/or NKp44 in the induction of NK-mediated cytotoxicity against the majority of target cells, whereas it represents the major triggering receptor in the killing of certain tumors. This novel receptor is associated with CD3zeta chains that become tyrosine phosphorylated upon sodium pervanadate treatment of NK cells. Molecular cloning of NKp30 cDNA revealed a member of the immunoglobulin superfamily, characterized by a single V-type domain and a charged residue in the transmembrane portion. Moreover, we show that NKp30 is encoded by the previously identified 1C7 gene, for which the function and the cellular distribution of the putative product were not identified in previous studies.

Show MeSH
Related in: MedlinePlus