RESUMEN
The expression of the Adenovirus serotype 5 (Ad5) E1A oncogene sensitizes tumor cells to natural killer (NK) cell-mediated killing and tumor rejection in vivo. These effects are dependent on the ability of E1A to bind the transcriptional coadaptor protein p300. To test the hypothesis that E1A up-regulates ligands recognized by the NKG2D-activating receptor, we stably transfected the highly tumorigenic mouse fibrosarcoma cell line MCA-205 with Ad5-E1A or a mutant form of E1A that does not interact with p300 (E1A-Deltap300). Ad5-E1A, but not E1A-Deltap300, up-regulated the expression of the NKG2D ligand retinoic acid early inducible (RAE)-1, but not murine ULBP-like transcript 1, another NKG2D ligand, in four independently derived MCA-205 transfectants. The up-regulation of RAE-1 by E1A targeted MCA-205 tumor cells to lysis by NK cells, resulting in NKG2D-dependent tumor rejection in vivo. Moreover, the up-regulation of NKG2D ligands by E1A was not limited to mouse tumor cells, as E1A also increased the expression of NKG2D ligands on primary baby mouse kidney cells, human MB435S breast cancer cells, and human H4 fibrosarcoma cells.
Asunto(s)
Adenoviridae , Fibrosarcoma/inmunología , Células Asesinas Naturales/inmunología , Receptores Inmunológicos/inmunología , Proteínas E1A de Adenovirus/genética , Proteínas E1A de Adenovirus/inmunología , Animales , Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Proteína p300 Asociada a E1A/genética , Proteína p300 Asociada a E1A/inmunología , Vectores Genéticos , Rechazo de Injerto/genética , Rechazo de Injerto/inmunología , Humanos , Riñón/inmunología , Ratones , Subfamilia K de Receptores Similares a Lectina de Células NK , Trasplante de Neoplasias , Neoplasias Experimentales/inmunología , Regiones Promotoras Genéticas/genética , Regiones Promotoras Genéticas/inmunología , Receptores Inmunológicos/genética , Receptores de Células Asesinas Naturales , Tretinoina/administración & dosificación , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/inmunologíaRESUMEN
Expressed predominantly on myeloid and natural killer (NK) cells, DAP12 is an adapter protein that can associate with a variety of receptors. To date, DAP12 has predominantly been characterized as an adapter protein that activates various myeloid and NK cell effector functions; however, recent findings have demonstrated that DAP12 can also inhibit myeloid functions. Here we review the dual functionality of DAP12 and present evidence that DAP12 can suppress as well as activate NK cells.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/fisiología , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Receptores Inmunológicos/fisiología , Animales , Humanos , Inmunidad Innata , Proteínas de la MembranaRESUMEN
CD45, a protein tyrosine phosphatase that regulates Src family kinases, is important for regulating T cell and B cell receptor signaling; however, little is known about how CD45 regulates immunoreceptor tyrosine-based activation motif (ITAM)-dependent natural killer (NK) cell receptor signaling and the resulting effector functions. NK cells from CD45-deficient mice are relatively competent for ITAM receptor-induced cell-mediated cytotoxicity, yet completely deficient for cytokine secretion after stimulation with ligands to or antibodies against NK1.1, CD16, Ly49H, Ly49D, and NKG2D. This deficiency in cytokine/chemokine production occurs at the level of mRNA expression. After receptor engagement, extracellular signal-regulated kinase and c-Jun N-terminal kinase activation was markedly perturbed, whereas p38 activation was not substantially affected. The pattern and amounts of basal tyrosine phosphorylation were altered in freshly isolated NK cells and were surprisingly and markedly increased in IL-2-expanded NK cells from CD45-/- mice. These findings indicate that CD45-dependent regulation of ITAM-dependent signaling pathways is essential for NK cell-mediated cytokine production but not cytolytic activity.
Asunto(s)
Secuencias de Aminoácidos , Citocinas/metabolismo , Células Asesinas Naturales/fisiología , Antígenos Comunes de Leucocito/metabolismo , Transducción de Señal/fisiología , Animales , Quimiocinas/genética , Quimiocinas/metabolismo , Citocinas/genética , Activación Enzimática , Antígenos Comunes de Leucocito/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Fosforilación , Receptores Inmunológicos/genética , Receptores Inmunológicos/inmunología , Tirosina/metabolismoRESUMEN
Irradiation-resistant natural killer (NK) cells in an F(1) recipient can reject parental bone marrow, and host NK cells can also prevent engraftment of allogeneic bone marrow. We show here that repopulating bone marrow cells in certain mouse strains expressed retinoic acid early inducible 1 proteins, which are ligands for the activating NKG2D NK cell receptor. Treatment with a neutralizing antibody to NKG2D prevented rejection of parental BALB/c bone marrow in (C57BL/6 x BALB/c) F(1) recipients and allowed engraftment of allogeneic BALB.B bone marrow in C57BL/6 recipients. Additionally, bone marrow from C57BL/6 mice transgenic for retinoic acid early inducible 1epsilon was rejected by syngeneic mice but was accepted after treatment with antibody to NKG2D. If other stem cells or tissues upregulate expression of NKG2D ligands after transplantation, NKG2D may contribute to graft rejection in immunocompetent hosts.
Asunto(s)
Rechazo de Injerto , Células Asesinas Naturales/inmunología , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Receptores Inmunológicos/inmunología , Receptores Inmunológicos/metabolismo , Animales , Anticuerpos Monoclonales , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/metabolismo , Trasplante de Médula Ósea , Proteínas Portadoras/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Células Asesinas Naturales/metabolismo , Ligandos , Ratones , Ratones Endogámicos , Ratones Noqueados , Ratones Transgénicos , Antígenos de Histocompatibilidad Menor/metabolismo , Subfamilia K de Receptores Similares a Lectina de Células NK , Receptores de Células Asesinas NaturalesRESUMEN
IL-21 is a cytokine that can promote the anti-tumor responses of the innate and adaptive immune system. Mice treated with IL-21 reject tumor cells more efficiently, and a higher percentage of mice remain tumor-free compared with untreated controls. In this study, we demonstrate that in certain tumor models IL-21-enhanced tumor rejection is NKG2D dependent. When engagement of the NKG2D receptor was prevented, either due to the lack of ligand expression on the tumor cells or due to direct blocking with anti-NKG2D mAb treatment, the protective effects of IL-21 treatment were abrogated or substantially diminished. Specifically, IL-21 only demonstrated a therapeutic effect in mice challenged with a retinoic acid early inducible-1delta-bearing lymphoma but not in mice bearing parental RMA tumors lacking NKG2D ligands. Furthermore, treatment with a blocking anti-NKG2D mAb largely prevented the therapeutic effect of IL-21 in mice challenged with the 4T1 breast carcinoma, the 3LL lung carcinoma, and RM-1 prostate carcinoma. By contrast, IL-21 did mediate beneficial effects against both the parental DA3 mammary carcinoma and DA3 tumors transfected with H60, a NKG2D ligand. We also observed that IL-21 treatment could enhance RMA-retinoic acid early inducible-1delta tumor rejection in RAG-1(-/-) deficient mice, thereby demonstrating that the IL-21-induced protective effect can be mediated by the innate immune system and that, in this case, IL-21 does not require the adaptive immune response. Collectively, these findings suggest that IL-21 therapy may work optimally against tumors that can elicit a NKG2D-mediated immune response.
Asunto(s)
Rechazo de Injerto/inmunología , Interleucinas/fisiología , Linfoma de Células T/inmunología , Linfoma de Células T/terapia , Receptores Inmunológicos/fisiología , Adyuvantes Inmunológicos/administración & dosificación , Adyuvantes Inmunológicos/fisiología , Adyuvantes Inmunológicos/uso terapéutico , Animales , Línea Celular Tumoral , Femenino , Rechazo de Injerto/genética , Rechazo de Injerto/metabolismo , Interleucinas/administración & dosificación , Interleucinas/uso terapéutico , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Ligandos , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/prevención & control , Neoplasias Pulmonares/secundario , Linfoma de Células T/genética , Linfoma de Células T/metabolismo , Neoplasias Mamarias Experimentales/inmunología , Neoplasias Mamarias Experimentales/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Antígenos de Histocompatibilidad Menor/metabolismo , Subfamilia K de Receptores Similares a Lectina de Células NK , Trasplante de Neoplasias , Receptores Inmunológicos/biosíntesis , Receptores Inmunológicos/metabolismo , Receptores de Células Asesinas Naturales , TransfecciónRESUMEN
CD8+ T cells require a signal through a costimulatory receptor in addition to TCR engagement to become activated. The role of CD28 in costimulating T cell activation is well established. NKG2D, a receptor found on NK cells, CD8+ alphabeta-TCR+ T cells, and gammadelta-TCR+ T cells, has also been implicated in T cell costimulation. In this study we have evaluated the role of NKG2D in costimulating mouse and human naive and effector CD8+ T cells. Unexpectedly, in contrast to CD28, NKG2D engagement by ligand or mAb is not sufficient to costimulate naive or effector CD8+ T cell responses in conventional T cell populations. While NKG2D did not costimulate CD8+ T cells on its own, it was able to modify CD28-mediated costimulation of human CD8+ T cells under certain contitions. It is, therefore, likely that NKG2D acts as a costimulatory molecule only under restricted conditions or requires additional cofactors.