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1.
Eur J Immunol ; 46(6): 1460-71, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27094031

RESUMO

CD1a expression is considered one of the major characteristics qualifying in vitro human dendritic cells (DCs) during their generation process. Here, we report that CD1A transcription is regulated by a mechanism involving the long and short isoforms of CD99. Using a lentiviral construct encoding for a CD99 short hairpin RNA, we were able to inhibit CD99 expression in human primary DCs. In such cells, CD1a membrane expression increased and CD1A transcripts were much higher in abundance compared to cells expressing CD99 long form (CD99LF). We also show that CD1A transcription is accompanied by a switch in expression from CD99LF to expression at comparable levels of both CD99 isoforms during immature DCs generation in vitro. We demonstrate that CD99LF maintains a lower level of CD1A transcription by up-regulating the phosphorylated form of the ATF-2 transcription factor and that CD99 short form (SF) is required to counteract this regulatory mechanism. Elucidation of the molecular mechanisms related to CD99 alternative splicing will be very helpful to better understand the transcriptional regulatory mechanism of CD1a molecules during DCs differentiation and its involvement in the immune response.


Assuntos
Antígeno 12E7/metabolismo , Fator 2 Ativador da Transcrição/metabolismo , Antígenos CD1/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Regulação da Expressão Gênica , Antígeno 12E7/genética , Antígenos CD1/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem Celular , Células Cultivadas , Células Dendríticas/citologia , Humanos , Monócitos/citologia , Monócitos/imunologia , Monócitos/metabolismo , Fosforilação , Isoformas de Proteínas , Transcrição Gênica
2.
J Am Soc Nephrol ; 27(5): 1517-33, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26567246

RESUMO

The phospholipase A2 receptor (PLA2R1) is the major autoantigen in idiopathic membranous nephropathy. However, the value of anti-PLA2R1 antibody titers in predicting patient outcomes is unknown. Here, we screened serum samples from 50 patients positive for PLA2R1 for immunoreactivity against a series of PLA2R1 deletion mutants covering the extracellular domains. We identified reactive epitopes in the cysteine-rich (CysR), C-type lectin domain 1 (CTLD1), and C-type lectin domain 7 (CTLD7) domains and confirmed the reactivity with soluble forms of each domain. We then used ELISAs to stratify 69 patients positive for PLA2R1 by serum reactivity to one or more of these domains: CysR (n=23), CysRC1 (n=14), and CysRC1C7 (n=32). Median ELISA titers measured using the full-length PLA2R1 antigens were not statistically different between subgroups. Patients with anti-CysR-restricted activity were younger (P=0.008), had less nephrotic range proteinuria (P=0.02), and exhibited a higher rate of spontaneous remission (P=0.03) and lower rates of renal failure progression (P=0.002) and ESRD (P=0.01) during follow-up. Overall, 31 of 69 patients had poor renal prognosis (urinary protein/creatinine ratio >4 g/g or eGFR<45 ml/min per 1.73 m(2) at end of follow-up). High anti-PLA2R1 activity and epitope spreading beyond the CysR epitope were independent risk factors of poor renal prognosis in multivariable Cox regression analysis. Epitope spreading during follow-up associated with disease worsening (n=3), whereas reverse spreading from a CysRC1C7 profile back to a CysR profile associated with favorable outcome (n=1). We conclude that analysis of the PLA2R1 epitope profile and spreading is a powerful tool for monitoring disease severity and stratifying patients by renal prognosis.


Assuntos
Autoanticorpos/imunologia , Epitopos/imunologia , Glomerulonefrite Membranosa/imunologia , Receptores da Fosfolipase A2/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico
4.
Nephrol Dial Transplant ; 29(12): 2334-42, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25063424

RESUMO

BACKGROUND: The predictive value of anti-M-type phospholipase A2 receptor (PLA2R1) autoantibodies for membranous nephropathy (MN) recurrence after renal transplantation remains controversial. METHODS: Our aim was to monitor anti-PLA2R1 IgG4 activity using a sensitive enzyme-linked immunosorbent assay in 15 kidney transplant recipients with MN, and to test the correlation between antibody titres and MN recurrence. RESULTS: Five patients never exhibited anti-PLA2R1 antibodies, and one of them relapsed. Ten patients (67%) had IgG4 anti-PLA2R1 antibodies at the time of transplantation and during follow-up. The presence of IgG4 anti-PLA2R1 antibodies at the time of kidney transplantation does not imply MN recurrence (P = 0.600, n = 15). However, a positive IgG4 anti-PLA2R1 activity during follow-up (>Month 6) was a significant risk factor for MN relapse (P = 0.0048, n = 10). Indeed, four patients had persistent IgG4 anti-PLA2R1 activity after transplantation and relapsed. Among them, one was successfully treated with rituximab. Another had persistently high IgG4 anti-PLA2R1 activity and exhibited a histological relapse but no proteinuria while on treatment with renin-angiotensin system inhibitors. In contrast, the six other patients who did not relapse exhibited a decrease of their IgG4 anti-PLA2R1 activity following transplant immunosuppression, including two with proteinuria due to biopsy-proven differential diagnoses. A weak transplant immunosuppressive regimen was also a risk factor of MN recurrence (P = 0.0048, n = 10). Indeed, the six patients who received both an induction therapy and a combined treatment with calcineurin inhibitors/mycophenolate exhibited a decrease of IgG4 anti-PLA2R1 activity and did not relapse, while the four patients who did not receive this strong immunosuppressive treatment association had persistently high IgG4 anti-PLA2R1 activity and relapsed. CONCLUSION: The monitoring of IgG4 anti-PLA2R1 titres during follow-up helps to predict MN recurrence, and a strong immunosuppressive treatment of anti-PLA2R1 positive patients may prevent recurrence.


Assuntos
Autoanticorpos/metabolismo , Glomerulonefrite Membranosa/imunologia , Transplante de Rim , Receptores da Fosfolipase A2/imunologia , Adulto , Biópsia , Ensaio de Imunoadsorção Enzimática , Feminino , Seguimentos , Glomerulonefrite Membranosa/diagnóstico , Glomerulonefrite Membranosa/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Recidiva , Estudos Retrospectivos , Fatores de Risco
5.
J Surg Res ; 176(2): 621-8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22137987

RESUMO

OBJECTIVES: We evaluated whether IGL-1, a graft preservation solution containing polyethylene glycol, improves the outcome of small bowel grafts in comparison to the University of Wisconsin (UW) solution in a pig allotransplantation model. MATERIALS AND METHODS: Seventeen pigs were randomly allocated to group 1 (n = 10; intestinal allotransplantation with IGL-1) and group 2 (n = 7; allotransplantation with UW). Pigs received no immunosuppression and were sacrificed on postoperative d (POD) 8. Intestinal specimens were obtained from the animal immediately before cold flushing (T0), 2 h after graft reperfusion (T1), and at sacrifice (T2). RESULTS: Survival rate to POD 8 was 50% in group 1 compared with 16% in group 2 (P < 0.05); 62% of pigs in group 1 did not present any acute cellular rejection (ACR) compared to 16% in group 2 (P < 0.05). Severe ACR rate was 25% in group 1 and 66% in group 2 (P < 0.05). iNOS activity and intestinal caspase 3 levels increased significantly between T0 and T1 in group 1 compared to group 2 (P < 0.05). Cell necrosis increased significantly between TO and T1 in group 2 compared with group 1 (P < 0.05) whereas cell apoptosis was significantly higher at T1 compared with T0 in group 1 in comparison to group 2. CONCLUSIONS: Our results show that IGL-1 improves intestinal graft viability as compared to UW solution, possibly by reducing graft immunogenicity and by favoring intestinal epithelial repair.


Assuntos
Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto/efeitos dos fármacos , Intestino Delgado/transplante , Soluções para Preservação de Órgãos/farmacologia , Polietilenoglicóis/farmacologia , Doença Aguda , Adenosina/farmacologia , Alopurinol/farmacologia , Animais , Apoptose/imunologia , Caspase 3/metabolismo , Feminino , Glutationa/farmacologia , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/mortalidade , Sobrevivência de Enxerto/imunologia , Terapia de Imunossupressão , Insulina/farmacologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Intestino Delgado/imunologia , Intestino Delgado/patologia , Rafinose/farmacologia , Traumatismo por Reperfusão/imunologia , Traumatismo por Reperfusão/mortalidade , Traumatismo por Reperfusão/prevenção & controle , Sus scrofa , Transplante Homólogo
6.
Blood ; 113(2): 347-57, 2009 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-18849489

RESUMO

By presenting antigenic peptides on the cell surface, human leukocyte antigen (HLA) class I molecules are critical for immune defense. Their surface density determines, to a large extent, the level of CD8(+) T cell-dependent immune reactions; their loss is a major mechanism of immune escape. Therefore, powerful processes should regulate their surface expression. Here we document the mechanisms used by CD99 to mediate HLA class I modulation. Up-regulation of HLA class I by IFN-gamma requires CD99. In the trans Golgi network (TGN), and up to the cell surface, CD99 and HLA class I are physically associated via their transmembrane domain. CD99 also binds p230/golgin-245, a coiled-coil protein that recycles between the cytosol and buds/vesicles of the TGN and which plays a fundamental role in trafficking transport vesicles. p230/golgin-245 is anchored within TGN membranes via its Golgin-97, RanBP1, IMh1p, P230 (GRIP) domain and the overexpression of which leads to surface and intracellular down-modulation of HLA class I molecules.


Assuntos
Antígenos CD/imunologia , Autoantígenos/imunologia , Linfócitos T CD8-Positivos/imunologia , Moléculas de Adesão Celular/imunologia , Complexo de Golgi/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Proteínas de Membrana/imunologia , Regulação para Cima/imunologia , Antígeno 12E7 , Antígenos CD/metabolismo , Antivirais/imunologia , Antivirais/farmacologia , Autoantígenos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Moléculas de Adesão Celular/metabolismo , Citosol/imunologia , Citosol/metabolismo , Complexo de Golgi/metabolismo , Antígenos HLA/biossíntese , Antígenos HLA/imunologia , Antígenos de Histocompatibilidade Classe I/biossíntese , Humanos , Imunidade Celular/fisiologia , Interferon gama/imunologia , Interferon gama/farmacologia , Células Jurkat , Proteínas de Membrana/metabolismo , Estrutura Terciária de Proteína/fisiologia , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/imunologia , Vesículas Transportadoras/imunologia , Vesículas Transportadoras/metabolismo , Regulação para Cima/efeitos dos fármacos
7.
EBioMedicine ; 73: 103679, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34763205

RESUMO

BACKGROUND: The immunogenicity of a two-dose mRNA COVID-19 vaccine regimen is low in kidney transplant (KT) recipients. Here, we provide a thorough assessment of the immunogenicity of a three-dose COVID-19 vaccine regimen in this population. METHODS: We performed a prospective longitudinal study in sixty-one KT recipients given three doses of the BNT162b2 COVID-19 vaccine. We performed semi-structured pharmacovigilance interviews and monitored donor-specific antibodies and kidney function. We compared levels of anti-spike IgG, pseudo-neutralization activity against vaccine homologous and heterologous variants, frequency of spike-specific interferon (IFN)-γ-secreting cells, and antigen-induced cytokine production 28 days after the second and third doses. FINDINGS: Reactions to vaccine were mild. One patient developed donor-specific anti-HLA antibodies after the second dose which could be explained by non-adherence to immunosuppressive therapy. Spike-specific IgG seroconversion raised from 44·3% (n=27) after the second dose to 62·3% (n=38) after the third dose (p<0·05). The mean level of spike-specific IgG increased from 1620 (SD, 3460) to 8772 (SD, 16733) AU/ml (p<0·0001). Serum neutralizing activity increased after the third dose for all variants of concern tested including the Delta variant (p<0·0001). The frequency of spike-specific IFN-γ-secreting cells increased from 19·9 (SD, 56·0) to 64·0 (SD, 76·8) cells/million PBMCs after the third dose (p<0·0001). A significant increase in IFN-γ responses was also observed in patients who remained seronegative after three doses (p<0·0001). INTERPRETATION: A third dose of the BNT162b2 vaccine increases both cross-variant neutralizing antibody and cellular responses in KT recipients with an acceptable tolerability profile. FUNDING: Nice University Hospital, University Cote d'Azur.


Assuntos
Anticorpos Neutralizantes/imunologia , Vacina BNT162/imunologia , COVID-19/imunologia , Transplante de Rim , Idoso , Anticorpos Neutralizantes/sangue , Autoanticorpos/sangue , Vacina BNT162/administração & dosagem , Vacina BNT162/efeitos adversos , COVID-19/prevenção & controle , COVID-19/virologia , Feminino , Rejeição de Enxerto/prevenção & controle , Antígenos HLA/imunologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunossupressores/uso terapêutico , Interferon gama/metabolismo , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Fatores de Risco , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia
8.
Transplant Proc ; 52(1): 204-211, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31889538

RESUMO

Cytomegalovirus (CMV) is the most common viral pathogen in kidney transplant recipients (KTRs), and CMV disease impacts patient and graft survivals. CMV-specific CD8 T cell mediated-immunity (CMI) may help to assess the risk of CMV disease and to adapt preventive treatment strategies. High-risk KTRs with CMV seropositive donors/seronegative recipients (D+/R-) were prospectively monitored after CMV prophylaxis discontinuation and during the first year post transplant for CMV viremia (World Health Organization standardization) and CMI (QuantiFERON-CMV). We analyzed the ability of CMI test to predict either subsequent spontaneous viral clearance or CMV disease after prophylaxis discontinuation in patients with asymptomatic viremia. We enrolled 12 consecutive (D+/R-) KTRs. Eleven patients developed a viremia during follow-up, but 7 of them (64%) exhibited a spontaneous viral clearance. At viremia onset, 6 of 11 patients (55%) had a positive CMI test, and all of them (6 of 6, 100%) had subsequent spontaneous viral clearance, compared with only 1 of 5 patients (20%) displaying a nonreactive CMI (P = .02). This latter patient exhibited a positive CMI test 15 days after viremia onset. Four of the 11 patients (36%) developed a CMV disease, and their CMI either remained nonreactive or became positive only after antiviral treatment. We conclude that D+/R- KTRs with asymptomatic viremia after prophylaxis discontinuation may benefit from QuantiFERON-CMV to predict when positive for the spontaneous viral clearance or when persistently negative or the development of a CMV disease.


Assuntos
Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/imunologia , Transplante de Rim , Viremia/diagnóstico , Adulto , Linfócitos T CD8-Positivos/imunologia , Citomegalovirus/imunologia , Infecções por Citomegalovirus/prevenção & controle , Feminino , Humanos , Imunidade Celular/imunologia , Masculino , Pessoa de Meia-Idade , Viremia/imunologia
9.
Mol Biol Cell ; 17(4): 1910-21, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16421247

RESUMO

CD99 was recently reported to be under control of the osteoblast-specific transcription factor Cbfa1 (RUNX2) in osteoblasts, suggesting a role in the phato-physiology of these cells. No extensive information is available on the role(s) of this molecule in malignant phenotype, and osteosarcoma, in particular, has never been studied. We report that in 11 different cell lines and 17 clinical samples CD99 expression is either undetectable or very low. Being expressed in the normal counterpart, we tested the hypothesis that CD99 down-regulation may have a role in osteosarcoma development and progression. CD99-forced expression in two osteosarcoma cell lines significantly reduced resistance to anoikis, inhibited growth in anchorage independence as well as cell migration, and led to abrogation of tumorigenic and metastatic ability. Therefore, the molecule acts as a potent suppressor of malignancy in osteosarcoma. CD99 gene transfection induces caveolin-1 up-regulation and the two molecules were found to colocalize on the cell surface. Treatment with antisense oligonucleotides to caveolin-1 abrogates the effects of CD99 on migration. The findings point to an antioncogenic role for CD99 in osteosarcoma, likely through the regulation of caveolin-1 and inhibition of c-Src kinase activity.


Assuntos
Antígenos CD/metabolismo , Neoplasias Ósseas/genética , Moléculas de Adesão Celular/metabolismo , Regulação Neoplásica da Expressão Gênica , Osteossarcoma/genética , Proteínas Supressoras de Tumor/metabolismo , Antígeno 12E7 , Antígenos CD/análise , Antígenos CD/genética , Neoplasias Ósseas/química , Neoplasias Ósseas/metabolismo , Caveolina 1/análise , Caveolina 1/genética , Caveolina 1/metabolismo , Moléculas de Adesão Celular/análise , Moléculas de Adesão Celular/genética , Linhagem Celular Tumoral , Membrana Celular/química , Movimento Celular/genética , Regulação para Baixo , Perfilação da Expressão Gênica , Genes Neoplásicos , Humanos , Osteoblastos/metabolismo , Osteossarcoma/química , Osteossarcoma/metabolismo , Transfecção , Proteínas Supressoras de Tumor/análise , Proteínas Supressoras de Tumor/genética , Regulação para Cima
10.
Front Immunol ; 10: 3069, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31998325

RESUMO

Membranous Nephropathy (MN) is an autoimmune disease associated with antibodies against podocyte proteins: M-type phospholipase A2 receptor (PLA2R1) or thrombospondin type-1 domain-containing 7A (THSD7A) in 70 and 3% of patients, respectively. Antibody titer is correlated with disease activity: rising during active disease and decreasing before remission. Therefore, decreasing PLA2R1-Antibodies titer has become an important goal of therapy. Rituximab a chimeric monoclonal antibody induces remission in 60-80% of primary MN patients. All monoclonal antibodies such as rituximab can elicit antidrug antibodies, which may interfere with therapeutic response. We aim to analyze the relevance of anti-rituximab antibodies on the outcome of MN after a first course of rituximab. Forty-four MN patients were included and treated with two 1 g infusions of rituximab at 2-weeks interval. Anti-rituximab antibodies, CD19 count, and clinical response were analyzed. Then, we (i) analyzed the association of anti-rituximab antibodies at month-6 with response to treatment: remission, relapse and the need for another rituximab course; (ii) confirmed if anti-rituximab antibodies could neutralize rituximab B-cells depletion; and (iii) tested whether anti-rituximab antibodies could cross-inhibit new humanized anti-CD20 therapies. Anti-rituximab antibodies were detected in 10 patients (23%). Seventeen patients received a second rituximab course after a median time of 12 months (7-12), following nine cases of resistance and eight relapses. Anti-rituximab antibodies were significantly associated with faster B-cell reconstitution at month-6 (75 [57-89] vs. 2 [0-41] cells/µl, p = 0.006), higher proteinuria 12 months after rituximab infusion (1.7 [0.7; 5.8] vs. 0.6 [0.2; 3.4], p = 0.03) and before treatment modification (3.5 [1.6; 7.1] vs. 1.7 [0.2; 1.7] p = 0.0004). Remission rate 6 months after rituximab was not different according to anti-rituximab status (p > 0.99) but the rate of relapse was significantly higher for patients with anti-rituximab antibodies (p < 0.001). These patients required more frequently a second course of rituximab infusions (7/10 vs. 10/34, p = 0.03). Anti-rituximab antibodies neutralized rituximab activity in 8/10 patients and cross-reacted with other humanized monoclonal antibodies in only two patients. Three patients with anti-rituximab antibodies were successfully treated with ofatumumab. Anti-rituximab antibodies could neutralize rituximab B cells cytotoxicity and impact clinical outcome of MN patients. Humanized anti-CD20 seems to be a satisfying therapeutic alternative for patients with anti-rituximab antibodies and resistant or relapsing MN.


Assuntos
Anticorpos Neutralizantes/imunologia , Glomerulonefrite Membranosa/complicações , Glomerulonefrite Membranosa/patologia , Fatores Imunológicos/efeitos adversos , Isoanticorpos/imunologia , Rituximab/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , Reações Cruzadas , Gerenciamento Clínico , Ensaio de Imunoadsorção Enzimática , Feminino , Glomerulonefrite Membranosa/tratamento farmacológico , Humanos , Fatores Imunológicos/uso terapêutico , Imunofenotipagem , Isoanticorpos/sangue , Masculino , Pessoa de Meia-Idade , Recidiva , Rituximab/uso terapêutico , Resultado do Tratamento
11.
Clin J Am Soc Nephrol ; 14(8): 1173-1182, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31340979

RESUMO

BACKGROUND AND OBJECTIVES: Different rituximab protocols are used to treat membranous nephropathy. We compared two rituximab protocols in patients with membranous nephropathy. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Twenty-eight participants from the NICE cohort received two infusions of 1-g rituximab at 2-week intervals, whereas 27 participants from the Prospective Randomized Multicentric Open Label Study to Evaluate Rituximab Treatment for Membranous Nephropathy (GEMRITUX) cohort received two infusions of 375 mg/m2 at 1-week interval. We measured serum rituximab levels and compared remission at month 6 and before any treatment modification and analyzed factors associated with remission and relapses. RESULTS: Remissions occurred in 18 (64%) versus eight (30%) from the NICE and GEMRITUX cohort (P=0.02) at month 6, respectively, and in 24 (86%) versus 18 (67%) participants (P=0.12) before treatment modification, respectively. Median time to remission was 3 [interquartile range (IQR), 3-9] and 9 [IQR, 6-12] months for NICE and GEMRITUX cohorts respectively (P=0.01). Participants from the NICE cohort had higher circulating level of rituximab and lower CD19 counts (3.3 µg/L [IQR, 0.0-10.8] versus 0.0 [IQR, 0.0-0.0] P<0.001 and 0.0 [IQR, 0.0-2.0] versus 16.5 [IQR, 2.5-31.0] P<0.001) at month 3, lower level of anti-PLA2R1 antibodies at month 6 (0.0 [IQR, 0.0-8.0] versus 8.3 [IQR, 0.0-73.5] P=0.03). In the combined study population, lower epitope spreading at diagnosis and higher rituximab levels at month 3 were associated with remissions at month 6 (13/26 (50%) versus 22/29 (76%) P=0.05 and 2.2 µg/ml [IQR, 0.0-10.9] versus 0.0 µg/ml [IQR, 0.0-0.0] P<0.001 respectively). All non-spreaders entered into remission whatever the protocol. Eight of the 41 participants who reached remission had relapses. Epitope spreading at diagnosis (8/8 (100%) versus 16/33 (48%) P=0.01) and incomplete depletion of anti-PLA2R1 antibodies at month 6 (4/8 (50%) versus 5/33 (9%) P=0.05) were associated with relapses. CONCLUSIONS: Our work suggests that higher dose rituximab protocol is more effective on depletion of B-cells and lack of epitope spreading is associated with remission of membranous nephropathy.


Assuntos
Glomerulonefrite Membranosa/tratamento farmacológico , Glomerulonefrite Membranosa/etiologia , Fatores Imunológicos/administração & dosagem , Receptores da Fosfolipase A2/fisiologia , Rituximab/administração & dosagem , Idoso , Estudos de Coortes , Feminino , Glomerulonefrite Membranosa/sangue , Humanos , Fatores Imunológicos/sangue , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Indução de Remissão , Rituximab/sangue
12.
Eur J Cancer ; 42(1): 91-6, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16326096

RESUMO

CD99 is a 32kDa surface glycoprotein that is involved in the migration of leukocytes, cell-cell adhesion and apoptosis of T cells and Ewing's sarcoma (ES) cells, two cell types with a high level of CD99 expression. Engagement of the molecule induces a rapid death signal that appears to be related to the level of expression of this antigen. The rapid apoptosis induced by agonistic anti-CD99 monoclonal antibodies is of clinical interest in ES, a tumour for which no new drugs have been described as clearly effective in the last 10 years. In this study, we show that an anti-CD99 monoclonal antibody can be used to advantage in association with doxorubicin. Striking effectiveness was observed against local tumours and metastases. No remarkably toxic effects of anti-CD99 monoclonal antibody were found in bone marrow against blood precursors. These results provide the necessary rationale and support for a novel modality of therapeutic intervention, which may have application in the care of patients with ES.


Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Moléculas de Adesão Celular/antagonistas & inibidores , Doxorrubicina/uso terapêutico , Sarcoma de Ewing/tratamento farmacológico , Antígeno 12E7 , Antígenos CD , Linhagem Celular Tumoral , Quimioterapia Combinada , Células-Tronco Hematopoéticas , Humanos
13.
Oncogene ; 23(33): 5664-74, 2004 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-15184883

RESUMO

CD99 is a unique 32-kDa cell surface molecule with broad cellular expression but still poorly understood biological functions. In cancer cells, CD99 is highly expressed in virtually all Ewing's sarcoma (ES). Engagement of CD99 induces fast homotypic aggregation of ES cells and caspase-independent apoptosis. In this study, we analysed signal transduction after CD99 engagement on ES cells. Findings obtained with selective inhibitors indicated that only actin cytoskeleton integrity was essential for cell-cell adhesion and apoptosis of ES cells. Indeed, CD99 stimulation induced actin repolymerization, further supporting the role of cytoskeleton in CD99 signaling. Gene expression profiling of ES cells after CD99 engagement showed modulation in the expression of 32 genes. Among the pool of upregulated genes reported to be involved in cell adhesion, we chose to analyse the role of zyxin, a cytoplasmic adherens junction protein found to play a role in the regulation of the actin cytoskeleton. Overexpression of zyxin after CD99 ligation was confirmed by real-time PCR and Western blot. Treatment of ES cells with zyxin antisense oligonucleotides inhibited CD99-induced cell aggregation and apoptosis, suggesting a functional role for this protein. Therefore, our findings indicate that CD99 functions occur through reorganization of cytoskeleton and identify actin and zyxin as the early signaling events driven by CD99 engagement.


Assuntos
Actinas/metabolismo , Glicoproteínas/metabolismo , Sarcoma de Ewing/metabolismo , Caspases/metabolismo , Agregação Celular , Morte Celular , Proteínas do Citoesqueleto , Humanos , Transdução de Sinais , Células Tumorais Cultivadas , Zixina
14.
Transplantation ; 79(3 Suppl): S8-S11, 2005 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-15699753

RESUMO

In order for the body to develop a good antibody response, B cells need to react intimately with antigen specific T cells. Experimental evidence using hapten-carriers revealed that T and B cells do not recognize the same epitope and this led to the view that the physical contact is mediated by the antigen. Although the modern concept of antigen presentation has changed our perception on how the antigen can bridge both cells, the basic virtues of earlier bridging models remain. Over the past few years, a number of surface ligand-receptor pathways have been described, most of them belonging either to the CD28/B7 Ig or to the TNF/TNFR-like families. These act in concert, whether they are agonist or antagonist, in a timely and spatially organized manner. They form cascades of successive induction and recruitment to ensure that T-B cooperation is closely controlled at all stages of antibody induction.


Assuntos
Linfócitos B/imunologia , Linfócitos T/imunologia , Animais , Formação de Anticorpos , Humanos , Imunidade Celular , Memória Imunológica , Receptores de Antígenos de Linfócitos B/imunologia
15.
FASEB J ; 16(14): 1946-8, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12368226

RESUMO

CD99, a unique integral membrane protein present on the surface of all human T cells, has previously been shown to regulate cell function and fate. In peripheral T cells, it triggers immediate activation of alpha4b1 integrin and cell arrest on inflamed vascular endothelium, whereas it mediates an apoptotic signal in double-positive thymocytes undergoing the selection process. Two isoforms of CD99 exist, a long form corresponding to the full-length protein and a short form harboring a deletion in the intracytoplasmic segment. Here, we show that while peripheral T cells display exclusive expression of the long form, double-positive thymocytes express both isoforms. Moreover, differential expression of these two CD99 molecules can lead to distinct functional outcomes. Expression of the long form in a CD99-deficient Jurkat T cell line is sufficient to promote CD99-induced cell adhesion, whereas coexpression of the two isoforms is required to trigger T-cell death. When coexpressed, the two proteins form covalent heterodimers, which locate within glycosphingolipidic rafts and induce sphingomyelin degradation. Cholesterol depletion experiments show that this localization is required for the induction of apoptosis. Thus, the surface expression pattern of CD99 isoforms determines T-cell functional outcomes.


Assuntos
Antígenos CD/metabolismo , Antígenos CD/fisiologia , Moléculas de Adesão Celular/metabolismo , Moléculas de Adesão Celular/fisiologia , Linfócitos T/imunologia , Antígeno 12E7 , Antígenos CD/análise , Apoptose , Adesão Celular , Moléculas de Adesão Celular/análise , Diferenciação Celular , Dimerização , Humanos , Células Jurkat , Microdomínios da Membrana/química , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiologia
16.
Biochimie ; 118: 104-15, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26296473

RESUMO

About 70% of patients with idiopathic membranous nephropathy (iMN) have autoantibodies to the phospholipase A2 receptor PLA2R1. We screened sera from iMN patients for their cross-reactivity to human (h), rabbit (rb) and mouse (m) PLA2R1 by western blot (WB) and antigen-specific ELISAs. All iMN patients recognized hPLA2R1 and rbPLA2R1 by WB, and a rbPLA2R1 ELISA was as sensitive as the standardized hPLA2R1 ELISA to monitor anti-PLA2R1 in patients with active disease or in drug-induced remission. In contrast, only 51% of patients were reactive to mPLA2R1 by WB, and a maximum of 78% were weakly to highly positive in the mPLA2R1 ELISA, suggesting that iMN patients exhibit different subsets of anti-PLA2R1 autoantibodies against epitopes that are shared or not among PLA2R1 orthologs. In a cohort of 41 patients with a mean follow-up of 42 months from anti-PLA2R1 assay, the detection of anti-mPLA2R1 autoantibodies was an independent predictor of clinical outcome in multivariate analysis (p = 0.009), and a ROC curve analysis identified a threshold of 605 RU/mL above which 100% of patients (12 patients) had a poor renal outcome (p < 0.001). A similar threshold could not be defined in hPLA2R1 and rbPLA2R1 ELISAs. We conclude that rbPLA2R1 is an alternative antigen to hPLA2R1 to measure anti-PLA2R1 in active disease while mPLA2R1 is a unique antigen that can detect a subset of anti-PLA2R1 autoantibodies present at high levels (>605 RU/mL) only in iMN patients at risk of poor prognosis, and is thus useful to predict iMN outcome.


Assuntos
Autoanticorpos/imunologia , Autoantígenos/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Glomerulonefrite Membranosa/diagnóstico , Receptores da Fosfolipase A2/imunologia , Animais , Western Blotting , Reações Cruzadas , Humanos , Coelhos
17.
Cancer Res ; 70(9): 3730-8, 2010 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-20388798

RESUMO

Ewing's sarcoma (EWS) is an aggressive tumor of children and young adults that requires intensive treatment. The search for new prognostic factors is very important to choose the most appropriate therapy and to better understand the biology of the disease for the development of new therapeutic tools. We found that Xg, a thus far poorly described molecule and member of the CD99 family, is expressed in EWS cell lines and EWS primary tumors. Immunohistochemical analysis confirmed the expression of Xg in 24% of patients. We found that Xg expression in EWS defines a subgroup of patients with worse prognosis compared with those with Xg-negative localized tumors, indicating a clinical relevance of Xg expression in EWS. Forced expression of Xg in an EWS cell line upregulated cell migration and invasion in vitro. Furthermore, knockdown of Xg expression with specific short hairpin RNA significantly reduced migration and invasion of EWS cells. Consistent with these data, in vivo xenotransplant studies in nude mice revealed that Xg expression increased the incidence and the number of metastases of EWS cells. Thus, Xg expression is associated with lower overall survival in EWS patients with localized tumors and is implicated in metastasis.


Assuntos
Antígenos de Grupos Sanguíneos/biossíntese , Moléculas de Adesão Celular/biossíntese , Sarcoma de Ewing/metabolismo , Adolescente , Animais , Neoplasias Ósseas/imunologia , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Criança , Feminino , Humanos , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Masculino , Camundongos , Camundongos Nus , Invasividade Neoplásica , Osteossarcoma/imunologia , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Prognóstico , Sarcoma de Ewing/imunologia , Sarcoma de Ewing/patologia
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