RESUMO
BACKGROUND AND PURPOSE: Cytomegalovirus (CMV) infection has recently been associated with a lower multiple sclerosis (MS) susceptibility, although it remains controversial whether it has a protective role or is merely an epiphenomenon related to westernization and early-life viral infections. We aimed to evaluate whether CMV serostatus may differ in patients with early MS as compared with patients with non-early MS, analyzing the putative association of this virus with MS clinical course and humoral immune responses against other herpesviruses. METHODS: Multicentric analysis was undertaken of 310 patients with MS (early MS, disease duration ≤5 years, n = 127) and controls (n = 155), evaluating specific humoral responses to CMV, Epstein-Barr virus and human herpesvirus-6, as well as T-cell and natural killer (NK)-cell immunophenotypes. RESULTS: Cytomegalovirus seroprevalence in early MS was lower than in non-early MS or controls (P < 0.01), being independently associated with disease duration (odds ratio, 1.04; 95% confidence interval, 1.01-1.08, P < 0.05). CMV+ patients with MS displayed increased proportions of differentiated T-cells (CD27-CD28-, CD57+, LILRB1+) and NKG2C+ NK-cells, which were associated with a lower disability in early MS (P < 0.05). CMV+ patients with early MS had an age-related decline in serum anti-EBNA-1 antibodies (P < 0.01), but no CMV-related differences in anti-human herpesvirus-6 humoral responses. CONCLUSIONS: Low CMV seroprevalence was observed in patients with early MS. Modification of MS risk attributed to CMV might be related to the induction of differentiated T-cell and NK-cell subsets and/or modulation of Epstein-Barr virus-specific immune responses at early stages of the disease.
Assuntos
Infecções por Citomegalovirus/complicações , Citomegalovirus/isolamento & purificação , Hipótese da Higiene , Esclerose Múltipla/virologia , Adulto , Anticorpos Antivirais/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Small-cell lung cancer (SCLC) is often associated with paraneoplastic syndromes. To assess the role of anti-neuronal autoantibodies (NAAs) as biomarkers of treatment outcome, we assessed NAAs in serial samples from SCLC patients treated with chemoimmunotherapy compared to chemotherapy alone. We evaluated 2 cohorts: in cohort 1 (C1), 47 patients received standard platinum/etoposide, and in cohort 2 (C2), 38 patients received ipilimumab, carboplatin and etoposide. Serum samples at baseline and subsequent time points were analyzed for the presence of NAAs. NAAs were detected at baseline in 25 patients (53.2%) in C1 and in 20 patients (52.6%) in C2 (most frequently anti-Sox1). NAA at baseline was associated with limited disease (75% vs 50%; p: 0.096) and better overall survival (15.1 m vs 11.7 m; p: 0.032) in C1. Thirteen patients (28.9%) showed 2 or more reactivities before treatment; this was associated with worse PFS (5.5 m vs 7.3 m; p: 0.005) in patients treated with chemoimmunotherapy. NAA titers decreased after therapy in 68.9% patients, with no differential patterns of change between cohorts. Patients whose NAA titer decreased after treatment, showed longer OS [18.5 m (95% CI: 15.8 - 21.2)] compared with those whose NAA increased [12.3 m (95% CI: 8.1 - 16.5; p 0.049)], suggesting that antibody levels correlate to tumor load. Our findings reinforce the role of NAAs as prognostic markers and tumor activity/burden in SCLC, warrant further investigation in their predictive role for immunotherapy and raise concern over the use of immunotherapy in patients with more than one anti-NAA reactivity.
RESUMO
Detection of posttransplant donor-specific anti-HLA antibodies (DSA) constitutes a risk factor for kidney allograft loss. Together with complement activation, NK-cell antibody-dependent cell mediated cytotoxicity (ADCC) has been proposed to contribute to the microvascular damage associated to humoral rejection. In the present observational exploratory study, we have tried to find a relationship of circulating donor-specific and non donor-specific anti-HLA antibodies (DSA and HLA non-DSA) with peripheral blood NK-cell subsets and clinical features in 393 renal allograft recipients. Multivariate analysis indicated that retransplantation and pretransplant sensitization were associated with detection of posttransplant DSA. Recipient female gender, DR mismatch and acute rejection were significantly associated with posttransplant DSA compared to HLA non-DSA. In contrast with patients without detectable anti-HLA antibodies, DSA and HLA non-DSA patients displayed lower proportions of NK-cells, associated with increased CD56(bright) and NKG2A(+) subsets, the latter being more marked in DSA cases. These differences appeared unrelated to retransplantation, previous acute rejection or immunosuppressive therapy. Although preliminary and observational in nature, our results suggest that the assessment of the NK-cell immunophenotype may contribute to define signatures of alloreactive humoral responses in renal allograft recipients.
Assuntos
Autoanticorpos/imunologia , Antígenos HLA/imunologia , Transplante de Rim , Células Matadoras Naturais/citologia , Adulto , Feminino , Humanos , Imunofenotipagem , Células Matadoras Naturais/imunologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Transplante HomólogoRESUMO
Natural killer (NK) and T-lymphocytes monitor human leukocyte antigen (HLA)-E expression through CD94:NKG2 heterodimers. Structural polymorphism is not a hallmark for NK-complex genes on chromosome 12, except for complete NKG2C deletion in some humans. We present a method for fast, simple and accurate assessment of NKG2C copy-number variation - presence or absence in the genome of an NKG2C gene, in homo- or heterozygosis, is detected by a single conventional polymerase chain reaction that yields amplicons of different lengths in each genotype. We have also determined the NKG2C genotypes of a reference cell panel comprising 13 NK- and tumour-cell lines and 39 Epstein-Barr virus transformed cells from the International Histocompatibility Workshop. Our results should facilitate research on the importance of NKG2C and its deletion for immunity.
Assuntos
Variações do Número de Cópias de DNA/genética , Células Matadoras Naturais/metabolismo , Subfamília C de Receptores Semelhantes a Lectina de Células NK/genética , Reação em Cadeia da Polimerase/métodos , Linfócitos T/metabolismo , Linhagem Celular Transformada , Linhagem Celular Tumoral , Cromossomos Humanos Par 12/genética , Primers do DNA , Dosagem de Genes , Herpesvirus Humano 4/genética , Heterozigoto , Homozigoto , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Subfamília C de Receptores Semelhantes a Lectina de Células NK/imunologia , Linfócitos T/citologia , Linfócitos T/imunologiaRESUMO
CD56(bright) NK cells, which may play a role in immunoregulation, are expanded in multiple sclerosis (MS) patients treated with immunomodulatory therapies such as daclizumab and interferon-beta (IFNß). Yet, whether this NK cell subset is directly involved in the therapeutic effect is unknown. As NK receptor (NKR) expression by subsets of NK cells and CD8+ T lymphocytes is related to MS clinical course, we addressed whether CD56(bright) NK cells and NKR in IFNß-treated MS patients differ according to the clinical response. IFNß was associated to lower LILRB1+ and KIR+NK cells, and higher NKG2A+NK cell proportions, an immunophenotypic pattern mainly found in responders. After IFNß treatment, a CD56(bright) NK cell expansion was significantly related to a positive clinical response. Our results reveal that IFNß may promote in responders changes in the NK cell immunophenotype, corresponding to the profile found at early maturation stages of this lymphocyte lineage.
Assuntos
Fatores Imunológicos/uso terapêutico , Interferon beta/uso terapêutico , Células Matadoras Naturais/imunologia , Esclerose Múltipla/tratamento farmacológico , Adulto , Antígeno CD56/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Estudos de Casos e Controles , Feminino , Humanos , Fatores Imunológicos/imunologia , Interferon beta/imunologia , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/imunologia , Receptores de Células Matadoras Naturais/imunologiaRESUMO
The origin of the epidemic of IgE-associated (allergic) diseases is unclear. MeDALL (Mechanisms of the Development of ALLergy), an FP7 European Union project (No. 264357), aims to generate novel knowledge on the mechanisms of initiation of allergy and to propose early diagnosis, prevention, and targets for therapy. A novel phenotype definition and an integrative translational approach are needed to understand how a network of molecular and environmental factors can lead to complex allergic diseases. A novel, stepwise, large-scale, and integrative approach will be led by a network of complementary experts in allergy, epidemiology, allergen biochemistry, immunology, molecular biology, epigenetics, functional genomics, bioinformatics, computational and systems biology. The following steps are proposed: (i) Identification of 'classical' and 'novel' phenotypes in existing birth cohorts; (ii) Building discovery of the relevant mechanisms in IgE-associated allergic diseases in existing longitudinal birth cohorts and Karelian children; (iii) Validation and redefinition of classical and novel phenotypes of IgE-associated allergic diseases; and (iv) Translational integration of systems biology outcomes into health care, including societal aspects. MeDALL will lead to: (i) A better understanding of allergic phenotypes, thus expanding current knowledge of the genomic and environmental determinants of allergic diseases in an integrative way; (ii) Novel diagnostic tools for the early diagnosis of allergy, targets for the development of novel treatment modalities, and prevention of allergic diseases; (iii) Improving the health of European citizens as well as increasing the competitiveness and boosting the innovative capacity of Europe, while addressing global health issues and ethical issues.
Assuntos
Hipersensibilidade/etiologia , Comportamento Cooperativo , União Europeia , Humanos , Hipersensibilidade/diagnóstico , Hipersensibilidade/tratamento farmacológico , Hipersensibilidade/prevenção & controle , Sistemas de Medicação , Fenótipo , Biologia de SistemasRESUMO
NK cell receptors (NKR) are expressed in subsets of NK and CD8+ T cells, lymphocytes involved in multiple sclerosis (MS) pathogenesis. Clinical implications of NKR expression in MS are unknown. Here, we show that the proportions of CD8+ T cells displaying LILRB1, an inhibitory NKR expressed at late stages of T cell differentiation, were directly related with age and MS duration, and inversely with the immunomodulatory therapy-dependent increase of CD56(bright) NK cells. Similar associations were found for KIR+ and CD56+ CD8+ T cells, whereas no age-related NKR distribution was perceived in controls. Moreover, active MS had lower LILRB1+ NK cells, and IFN-ß-treated patients exhibited a phenotypic profile related to shorter disease evolution. Progressive accumulation of terminally differentiated T lymphocytes and experienced NK cells in MS, presumably stimulated in response to a persistent challenge and modulated by IFN-ß therapy, may support the analysis of NKR distribution as new biomarkers.
Assuntos
Antígenos CD/metabolismo , Interferon beta/uso terapêutico , Linfócitos/metabolismo , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/imunologia , Receptores Imunológicos/metabolismo , Receptores de Células Matadoras Naturais/metabolismo , Adulto , Envelhecimento/metabolismo , Anticorpos/sangue , Anticorpos/imunologia , Biomarcadores/metabolismo , Antígeno CD56/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Contagem de Células , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/imunologia , Feminino , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/metabolismo , Receptor B1 de Leucócitos Semelhante a Imunoglobulina , Leucócitos Mononucleares/citologia , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico , Esclerose Múltipla/metabolismo , Esclerose Múltipla Crônica Progressiva/diagnóstico , Esclerose Múltipla Crônica Progressiva/tratamento farmacológico , Esclerose Múltipla Crônica Progressiva/imunologia , Esclerose Múltipla Crônica Progressiva/metabolismo , Esclerose Múltipla Recidivante-Remitente/diagnóstico , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Esclerose Múltipla Recidivante-Remitente/imunologia , Esclerose Múltipla Recidivante-Remitente/metabolismo , Subfamília C de Receptores Semelhantes a Lectina de Células NK/metabolismo , Receptores KIR/metabolismo , Recidiva , Fatores de TempoRESUMO
The genetic susceptibility to multiple sclerosis (MS) is only partially explained, and it shows geographic variations. We analyse here two series of Spanish patients and healthy controls and show that relapsing MS (R-MS) is associated with a gene deletion affecting the hypothetically soluble leukocyte immunoglobulin (Ig)-like receptor A3 (LILRA3, 19q13.4), in agreement with an earlier finding in German patients. Our study points to a gene-dose-dependent, protective role for LILRA3, the deletion of which synergizes with HLA-DRB1(*)1501 to increase the risk of R-MS. We also investigated whether the risk of suffering R-MS might be influenced by the genotypic diversity of killer-cell Ig-like receptors (KIRs), located only approximately 400 kb telomeric to LILRA3, and implicated in autoimmunity and defence against viruses. The relationship of LILRA3 deletion with R-MS is not secondary to linkage disequilibrium with a KIR gene, but we cannot exclude some contributions of KIR to the genetic susceptibility to R-MS.
Assuntos
Deleção de Genes , Antígenos HLA-DR/genética , Esclerose Múltipla/genética , Receptores Imunológicos/genética , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Criança , Feminino , Variação Genética , Genótipo , Cadeias HLA-DRB1 , Humanos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/epidemiologia , Receptores KIR/genética , Espanha/epidemiologia , Adulto JovemRESUMO
The aim of this work was to study the expression and function of the inhibitory receptor ILT2/CD85j in peripheral blood mononuclear cells (PBMC) from patients with systemic lupus erythematosus (SLE). We studied 23 SLE patients as well as 17 patients with rheumatoid arthritis, 10 with fibromyalgia, and 23 healthy individuals. We found a variable level of expression of ILT2 in the PBMC from both SLE patients and controls, with no significant differences among them. However, when the expression of this receptor was assessed in cell subsets, significantly lower levels were detected in CD19+ lymphocytes from SLE patients compared with healthy controls. Functional assays performed in unfractionated PBMC, showed a significant diminished inhibitory activity of ILT2 in CD4+ and CD8+ cell subsets from SLE patients compared to either rheumatoid arthritis or fibromyalgia patients, and healthy individuals. Our results show that the PBMC from some patients with SLE show a defective expression of ILT2, and that most of them exhibit a poor function of this inhibitory receptor.
Assuntos
Antígenos CD/fisiologia , Leucócitos Mononucleares/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/metabolismo , Receptores Imunológicos/fisiologia , Adulto , Antígenos CD/imunologia , Apoptose , Artrite Reumatoide/imunologia , Artrite Reumatoide/metabolismo , Estudos de Casos e Controles , Ciclo Celular , Células Cultivadas , Feminino , Fibromialgia/imunologia , Fibromialgia/metabolismo , Humanos , Receptor B1 de Leucócitos Semelhante a Imunoglobulina , Leucócitos Mononucleares/metabolismo , Lúpus Eritematoso Sistêmico/metabolismo , Ativação Linfocitária , Subpopulações de Linfócitos/citologia , Masculino , Pessoa de Meia-Idade , Receptores Imunológicos/imunologiaRESUMO
Human cytomegalovirus (HCMV) infection is a paradigm of the complexity reached by host-pathogen interactions. To avoid recognition by cytotoxic T lymphocytes (CTL) HCMV inhibits the expression of HLA class I molecules. As a consequence, engagement of inhibitory killer immunoglobulin-like receptors (KIR), CD94/NKG2A, and CD85j (ILT2 or LIR-1) natural killer cell receptors (NKR) specific for HLA class I molecules is impaired, and infected cells become vulnerable to an NK cell response driven by activating receptors. In addition to the well-defined role of the NKG2D lectin-like molecule, the involvement of other triggering receptors (i.e., activating KIR, CD94/NKG2C, NKp46, NKp44, and NKp30) in the response to HCMV is being explored. To escape from NK cell-mediated surveillance, HCMV interferes with the expression of NKG2D ligands in infected cells. In addition, the virus may keep NK inhibitory receptors engaged preserving HLA class I molecules with a limited role in antigen presentation (i.e., HLA-E) or, alternatively, displaying class I surrogates. Despite considerable progress in the field, a number of issues regarding the involvement of NKR in the innate immune response to HCMV remain uncertain.
Assuntos
Citomegalovirus/imunologia , Células Matadoras Naturais/imunologia , Receptores Imunológicos/metabolismo , Infecções por Citomegalovirus/imunologia , Humanos , Imunidade Inata , Ativação LinfocitáriaRESUMO
Downmodulation of major histocompatibility complex (MHC) class I molecules by cytomegalovirus (CMV) impairs the engagement of specific leucocyte-inhibitory receptors, rendering infected cells vulnerable to natural killer (NK) cells. Members of the murine Ly49 and human KIR families, CD85j (ILT2 or leucocyte Ig-like receptor-1), as well as the CD94/NKG2A-inhibitory killer lectin-like receptor (KLR) fulfil this surveillance role. On the other hand, NK-activating receptors specific to ligands expressed on virus-infected cells may overcome the control by inhibitory receptors. In this regard, NKG2D and Ly49H lectin-like molecules trigger NK-cell functions recognizing, respectively class I-related stress-inducible molecules and the m157 murine CMV glycoprotein. Among a variety of immune evasion strategies, CMV promotes the synthesis of class I surrogates and selectively preserves the expression of some class I molecules in infected cells; moreover, CMV interferes with the expression of ligands for NKG2D. We herein review these aspects of the host-pathogen interaction, discussing a number of open issues.
Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células Matadoras Naturais/imunologia , Glicoproteínas de Membrana/imunologia , Receptores Imunológicos/imunologia , Animais , Antígenos CD/imunologia , Antígenos Virais/imunologia , Citotoxicidade Imunológica , Humanos , CamundongosRESUMO
NK cells and T lymphocyte subsets recognize Major Histocompatibility Complex (MHC) class I molecules by means of inhibitory receptors of the KIR (K i l l e r Immunoglobulin-like Receptors) family, which includes as well molecules with an activating function. The panel of mono - clonal antibodies (mAbs) available to study the KIR pro t e i n s is quite limited. In this work we describe two novel mAbs, ter - med HP-MA3 (IgG1) and HP-MA4 (IgG2b), that specifically recognize both KIR2DL1 and its activating homologue KIR2DS1 (AU)
Las células natural killer (NK) y algunas subpoblaciones de linfocitos T reconocen moléculas del Complejo Principal de Histocompatibilidad (MHC) de clase I mediante re c e p t o res inhibidores de la familia KIR (K i l l e r Immunoglobulin-like Receptors), que incluye también algunos re c e p t o res homólogos con función activadora. El conjunto de anticuerpos monoclonales (AcMo) disponible para el estudio de los KIR es muy limitado. En este trabajo se describen dos nuevos AcMos, denominados HP-MA3 (IgG1) y HP-MA4 (IgG2b), que reconocen específicamente tanto el receptor inhibidor KIR2DL1 como su homólogo activador KIR2DS1 (AU)
Assuntos
Humanos , Anticorpos Monoclonais/imunologia , Receptores KIR/imunologia , Especificidade de Anticorpos/imunologia , Complexo Principal de Histocompatibilidade/imunologia , Células Matadoras Naturais/imunologia , Citometria de Fluxo , Citotoxicidade ImunológicaRESUMO
In this paper we describe the clinical and molecular features of a new case (GOR) of homozygous human TAP2 deficiency, analysing the phenotype and function of NK cells. The patient presented from infancy with recurrent sinopulmonary infections; a selective IgG2 deficiency, negative antibody response to polysaccharide vaccination and low level of cell surface expression of HLA class I antigens were found. The sequence of TAP2 gene identified a single mutation, a C to T substitution changing the CGA arg codon at amino acid 220 into TGA stop codon in exon 3. By using MoAbs for KIRs, CD94, CD94/NKG2A and ILT2 we observed, in agreement with others, that the latter two receptors were overexpressed on TAP2-deficient NK cells. The inhibitory CD94/NKG2A and triggering CD94/NKG2C NK receptors, specific for HLA-E, appeared to be functional in a limited number of NK clones that could be expanded in vitro. Expression of HLA-E was virtually undetectable in GOR B-LCL and very faint in PBMC, further supporting that interactions of class I leader sequence nonamers with HLA-E in the ER depend on a functional TAP complex.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Cisteína Endopeptidases , Células Matadoras Naturais/imunologia , Complexos Multienzimáticos , Imunodeficiência Combinada Severa/imunologia , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Membro 3 da Subfamília B de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/metabolismo , Sequência de Aminoácidos , Células Cultivadas , Testes Imunológicos de Citotoxicidade , Antígenos de Histocompatibilidade Classe I/metabolismo , Homozigoto , Humanos , Imunofenotipagem , Células K562 , Dados de Sequência Molecular , Mutação , Complexo de Endopeptidases do Proteassoma , Proteínas/metabolismo , Imunodeficiência Combinada Severa/genética , Subpopulações de Linfócitos T/classificaçãoRESUMO
Among various strategies to evade the host immune response, some viruses like human cytomegalovirus (HCMV) interfere with surface MHC class I expression and antigen presentation to T lymphocytes. The ability of natural killer (NK) cells to detect MHC class I molecules through inhibitory receptors can be envisaged as an adaptation of the immune system for responding to such pathological alterations. To fulfil that role, rodents use members of the Ly49 C-type lectin superfamily, whereas primates employ killer immunoglobulin-like receptors and the immunoglobulin-like transcript 2/leucocyte immunoglobulin-like receptor-1 receptor. CD94/NKG2 lectin-like heterodimers represent the most conserved receptor system for MHC class I molecules; by interacting with human HLA-E or murine Qa-1b, CD94/NKG2A inhibitory receptors broadly probe the biosynthesis pathway of other class I molecules. Reciprocally, HCMV has developed mechanisms to evade the NK response while modulating HLA class Ia expression. The ability of HCMV to maintain surface levels of HLA-E and to express an HLA class I surrogate (UL18) are herein discussed in the context of the interplay with human NKR systems.
Assuntos
Citomegalovirus/imunologia , Citomegalovirus/patogenicidade , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Células Matadoras Naturais/imunologia , Adaptação Fisiológica , Animais , Humanos , Camundongos , Receptores Imunológicos/metabolismo , Proteínas Virais/imunologia , Antígenos HLA-ERESUMO
BACKGROUND AND OBJECTIVES: The lymphoproliferative disorders of large granular lymphocytes (LGLD) are divided into two groups: T-cell type and NK-cell type. These entities may be either asymptomatic or associated with autoimmune manifestations (especially cytopenias). A number of surface receptors, expressed by NK-cells and some T-lymphocyte subsets repress cytotoxicity and cytokine production upon ligation with HLA class I molecules and are clonally expressed in theses lymphoproliferative disorders. These cytotoxic lymphocytes can lyse erythroid progenitors in vitro, and the physiologic lower levels of HLA class I antigens on the erythroid lineage may contribute to this form of autoimmunity. It is conceivable that the clinical outcome of T-LGLD might be influenced by the expression of MHC class I inhibitory receptors. DESIGN AND METHODS: We analyzed the surface expression of these molecules, lectin-like heterodimers (CD94/NKG2A) or killer immunoglobulin (Ig)-like receptors (KIR) and another Ig-like inhibitory receptor, termed ILT2 or LIR-1 in CD8+ cells from 12 cases of ab T-LGLD using specific monoclonal antibodies. RESULTS: None of the LGLD cases had anemia and 11 of 12 patients remain asymptomatic. KIR and CD94/NKG2A expression was detected on CD8+ populations only in some cases of T-LGLD. By contrast, our observations revealed that ILT2 expression was markedly higher in CD8+ cells from LGLD patients than from healthy donors. INTERPRETATION AND CONCLUSIONS: Expression of the ILT2 inhibitory receptor for HLA class I molecules on LGLD cells might indeed contribute to preventing their autoreactivity. Further studies are required to evaluate the expression/function of the ILT2 receptor in patients who eventually become symptomatic. The development of cytopenias in LGLD patients must involve other self-reactive activating receptors. Analysis of the expression and function of triggering NKR in LGLD needs to be carefully addressed.
Assuntos
Antígenos CD/metabolismo , Linfócitos T CD8-Positivos/patologia , Leucemia Linfoide/patologia , Receptores Imunológicos/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos T CD8-Positivos/metabolismo , Estudos de Casos e Controles , Células Clonais/metabolismo , Células Clonais/patologia , Feminino , Antígenos de Histocompatibilidade Classe I , Humanos , Leucemia Linfoide/metabolismo , Receptor B1 de Leucócitos Semelhante a Imunoglobulina , Masculino , Pessoa de Meia-IdadeRESUMO
El reconocimiento específico de moléculas HLA de clase I reprime las funciones de las células NK. Un grupo de receptores de superficie con función inhibidora pertenece a la superfamilia de las inmunoglobulinas (Ig-SF), mientras que otros son moléculas tipo lectina. Todos ellos presentan en su tallo citoplasmático secuencias denominadas ITIM (Immunoreceptor Tyrosine-Based Inhibition Motifs) que contribuyen al ensamblaje de tirosinfosfatasas con dominios SH2 (SHP). Las señales inhibidoras contrarrestan la función de otro grupo de receptores activadores; entre las moléculas que disparan la actividad NK algunas son homólogas a los receptores inhibidores e interaccionan también con proteínas del MHC de clase I. Este tipo de mecanismo de regulación, basado en el equilibrio establecido entre señales contrapuestas, opera igualmente en otros leucocitos implicando a diferentes receptores (AU)
Assuntos
Animais , Humanos , Células Matadoras Naturais/fisiologia , Receptores Imunológicos/fisiologia , Genes MHC Classe I/fisiologia , Proteínas de Membrana/fisiologia , LeucócitosRESUMO
The CD94/NKG2C heterodimer constitutes an activating receptor involved in NK cell-mediated recognition of the class lb molecule HLA-E. It transduces the triggering signal through an ITAM-bearing molecule, DAP12/KARAP, coupled non-covalently to the receptor. Here we show that specific engagement of the receptor complex expressed on the surface of an NK clone induced the phosphorylation of mitogen-activated protein kinase (MAPK). By the use of the MEK inhibitor PD098059 we demonstrate that the MAPK pathway participates in the CD94-dependent TNF-alpha production and cytotoxicity. Moreover, we transferred the activating function by transfection of the heterologous RBL cell line with CD94/NKG2-C/DAP12. In this system, cross-linking of the receptor induced calcium mobilization, serotonin release and phosphorylation of MAPK.
Assuntos
Antígenos CD/imunologia , Antígenos HLA/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células Matadoras Naturais/imunologia , Lectinas Tipo C , Sistema de Sinalização das MAP Quinases , Glicoproteínas de Membrana/imunologia , Receptores Imunológicos/imunologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Antígenos CD/genética , Citotoxicidade Imunológica , Inibidores Enzimáticos/farmacologia , Precursores Enzimáticos/fisiologia , Flavonoides/farmacologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Células Matadoras Naturais/enzimologia , Leucemia Basofílica Aguda/patologia , Glicoproteínas de Membrana/genética , Proteínas de Membrana , Subfamília C de Receptores Semelhantes a Lectina de Células NK , Subfamília D de Receptores Semelhantes a Lectina de Células NK , Fosforilação , Processamento de Proteína Pós-Traducional , Estrutura Terciária de Proteína , Proteínas Tirosina Quinases/fisiologia , Ratos , Receptores Imunológicos/química , Receptores Imunológicos/genética , Receptores de Células Matadoras Naturais , Proteínas Recombinantes de Fusão/imunologia , Serotonina/metabolismo , Quinase Syk , Transfecção , Células Tumorais Cultivadas , Antígenos HLA-ERESUMO
The compartmentalization of plasma membrane proteins has a key role in regulation of lymphocyte activation and development of immunity. We found that the proline-rich tyrosine kinase-2 (PYK-2/RAFTK) colocalized with the microtubule-organizing center (MTOC) at the trailing edge of migrating natural killer (NK) cells. When polyclonal NK cells bound to K562 targets, PYK-2 translocated to the area of NK-target cell interaction. The specificity of this process was assessed with NK cell clones bearing activatory or inhibitory forms of CD94/NKG2. The translocation of PYK-2, MTOC, and paxillin to the area of NK-target cell contact was regulated upon specific recognition of target cells through NK cell receptors, controlling target cell killing. Furthermore, parallel in vitro kinase assays showed that PYK-2 was activated in response to signals that specifically triggered its translocation and NK cell mediated cytotoxicity. The overexpression of both the wt and a dominant-negative mutant of PYK-2, but not ZAP-70 wt, prevented the specific translocation of the MTOC and paxillin, and blocked the cytotoxic response of NK cells. Our data indicate that subcellular compartmentalization of PYK-2 correlates with effective signal transduction. Furthermore, they also suggest an important role for PYK-2 on the assembly of the signaling complexes that regulate the cytotoxic response.
Assuntos
Citotoxicidade Imunológica , Células Matadoras Naturais/metabolismo , Lectinas Tipo C , Proteínas Tirosina Quinases/metabolismo , Animais , Antígenos CD/imunologia , Adesão Celular , Linhagem Celular , Movimento Celular , Proteínas do Citoesqueleto/metabolismo , Ativação Enzimática , Imunofluorescência , Quinase 2 de Adesão Focal , Células Matadoras Naturais/imunologia , Glicoproteínas de Membrana/imunologia , Mutação , Subfamília D de Receptores Semelhantes a Lectina de Células NK , Paxilina , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinases/genética , Transdução de Sinais , Transfecção , Vaccinia virus/genética , Proteína-Tirosina Quinase ZAP-70RESUMO
NK cells recognize several HLA class Ib molecules employing both immunoglobulin-like (Ig-like) and C-type lectin receptors. The CD94/NKG2 and NKG2D lectin-like molecules, respectively, interact with HLA-E and MICA; CD94/NKG2A functions as an inhibitory receptor, while CD94/NKG2C and NKG2D trigger NK cell activity. HLA-E predominantly presents nonamers from the leader sequences of other class I molecules; a peptide derived from HLA-G1 constitutes the highest affinity ligand for both CD94/NKG2 receptors. Members of the Ig-like transcript (ILT) or leucocyte Ig-like receptor (LIR) family (ILT2 or LIR-1 and ILT4 or LIR-2), expressed by other leucocyte lineages, interact with a broad spectrum of HLA class Ia molecules and HLA-G1. Among Ig-like KIRs, the KIR2DL4 (p49) receptor has been shown to specifically recognize HLA-G1; this molecule displays an unusual hybrid structure, sharing features with inhibitory and triggering KIRs.