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1.
ESMO Open ; 9(1): 102199, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38071928

RESUMO

BACKGROUND: Brain metastasis (BRM) is uncommon in gastroesophageal cancer. As such, clinicopathologic and molecular determinants of BRM and impact on clinical outcome remain incompletely understood. METHODS: We retrospectively analyzed clinicopathologic data from advanced esophageal/gastroesophageal junction (E/GEJ) patients at Johns Hopkins from 2003 to 2021. We investigated the association between several clinical and molecular features and the occurrence of BRM, with particular focus on human epidermal growth factor receptor 2 (HER2) overexpression. Survival outcomes and time to BRM onset were also evaluated. RESULTS: We included 515 patients with advanced E/GEJ cancer. Tumors were 78.3% esophageal primary, 82.9% adenocarcinoma, 31.0% HER2 positive. Cumulative incidence of BRM in the overall cohort and within HER2+ subgroup was 13.8% and 24.3%, respectively. HER2 overexpression was associated with increased risk of BRM [odds ratio 2.45; 95% confidence interval (CI) 1.10-5.46]. On initial presentation with BRM, 50.7% had a solitary brain lesion and 11.3% were asymptomatic. HER2+ status was associated with longer median time to onset of BRM (14.0 versus 6.3 months, P < 0.01), improved median progression free survival on first-line systemic therapy (hazard ratio 0.35, 95% CI 0.16-0.80), and improved median overall survival (hazard ratio 0.20, 95% CI 0.08-0.54) in patients with BRM. CONCLUSION: HER2 overexpression identifies a gastroesophageal cancer molecular subtype that is significantly associated with increased risk of BRM, though with later onset of BRM and improved survival likely reflecting the impact of central nervous system-penetrant HER2-directed therapy. The prevalence of asymptomatic and solitary brain lesions suggests that brain surveillance for HER2+ patients warrants prospective investigation.


Assuntos
Adenocarcinoma , Neoplasias Encefálicas , Neoplasias Esofágicas , Neoplasias Gástricas , Humanos , Estudos Retrospectivos , Estudos Prospectivos , Neoplasias Esofágicas/patologia , Junção Esofagogástrica/metabolismo , Junção Esofagogástrica/patologia
2.
Ann Oncol ; 29(8): 1853-1860, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982279

RESUMO

Background: Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed. Patients and methods: The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic 'tumor' measurements were also assessed. Results: We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation-dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death-cholesterol clefts; and (iii) tissue repair-neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P < 0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop 'Immune-Related Pathologic Response Criteria' (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT [median per-case %RVT variability 5% (0%-29%) versus 10% (0%-58%), P = 0.007] and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P = 0.002). Conclusions: irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/terapia , Neoplasias Pulmonares/terapia , Pulmão/patologia , Adulto , Antineoplásicos Imunológicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Estudos de Viabilidade , Humanos , Ipilimumab/farmacologia , Ipilimumab/uso terapêutico , Pulmão/imunologia , Pulmão/cirurgia , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Terapia Neoadjuvante/métodos , Neoplasia Residual , Nivolumabe/farmacologia , Nivolumabe/uso terapêutico , Pneumonectomia , Prognóstico , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Reprodutibilidade dos Testes , Resultado do Tratamento
3.
Dis Esophagus ; 28(7): 644-51, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25059343

RESUMO

Neoadjuvant therapy has proven to be effective in the reduction of locoregional recurrence and mortality for esophageal cancer. However, induction treatment has been reported to be associated with increased risk of postoperative complications. We therefore compared outcomes after esophagectomy for esophageal cancer for patients who underwent neoadjuvant therapy and patients treated with surgery alone. Using the American College of Surgeons National Surgical Quality Improvement Program database (2005-2011), we identified 1939 patients who underwent esophagectomy for esophageal cancer. Seven hundred and eight (36.5%) received neoadjuvant therapy, while 1231 (63.5%) received no neoadjuvant therapy within 90 days prior to surgery. Primary outcome was 30-day mortality, and secondary outcomes included overall and serious morbidity, length of stay, and operative time. Patients who underwent neoadjuvant treatment were younger (62.3 vs. 64.7, P < 0.001), were more likely to have experienced recent weight loss (29.4% vs. 15.9%, P < 0.001), and had worse preoperative hematological cell counts (white blood cells <4.5 or >11 × 10(9) /L: 29.3% vs. 15.0%, P < 0.001; hematocrit <36%: 49.7% vs. 30.0%, P < 0.001). On unadjusted analysis, 30-day mortality, overall, and serious morbidity were comparable between the two groups, with the exception of the individual complications of venous thromboembolic events and bleeding transfusion, which were significantly lower in the surgery-only patients (5.71% vs. 8.27%, P = 0.027; 6.89% vs. 10.57%, P = 0.004; respectively). Multivariable and matched analysis confirmed that 30-day mortality, overall, and serious morbidity, as well as prolonged length of stay, were comparable between the two groups of patients. An increasing trend of preoperative neoadjuvant therapy for esophageal cancer was observed through the study years (from 29.0% in 2005-2006 to 44.0% in 2011, P < 0.001). According to our analysis, preoperative neoadjuvant therapy for esophageal cancer does not increase 30-day mortality or the overall risk of postoperative complications after esophagectomy.


Assuntos
Neoplasias Esofágicas/terapia , Esofagectomia/mortalidade , Terapia Neoadjuvante/mortalidade , Complicações Pós-Operatórias/mortalidade , Fatores Etários , Idoso , Biomarcadores/sangue , Neoplasias Esofágicas/sangue , Neoplasias Esofágicas/mortalidade , Esofagectomia/efeitos adversos , Feminino , Humanos , Tempo de Internação , Contagem de Leucócitos , Masculino , Análise por Pareamento , Pessoa de Meia-Idade , Terapia Neoadjuvante/efeitos adversos , Duração da Cirurgia , Complicações Pós-Operatórias/etiologia , Período Pós-Operatório , Estudos Retrospectivos , Resultado do Tratamento , Redução de Peso
4.
Br J Pharmacol ; 166(3): 981-90, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22145625

RESUMO

BACKGROUND AND PURPOSE: Previous studies have linked a reduction in pH in airway, caused by either environmental factors, microaspiration of gastric acid or inflammation, with airway smooth muscle (ASM) contraction and increased airway resistance. Neural mechanisms have been shown to mediate airway contraction in response to reductions in airway pH to < 6.5; whether reduced extracellular pH (pHo) has direct effects on ASM is unknown. EXPERIMENTAL APPROACH: Intracellular signalling events stimulated by reduced pHo in human cultured ASM cells were examined by immunoblotting, phosphoinositide hydrolysis and calcium mobilization assays. ASM cell contractile state was examined using magnetic twisting cytometry. The expression of putative proton-sensing GPCRs in ASM was assessed by real-time PCR. The role of ovarian cancer G protein-coupled receptor 1 (OGR1 or GPR68) in acid-induced ASM signalling and contraction was assessed in cultures subjected to siRNA-mediated OGR1 knockdown. KEY RESULTS: ASM cells responded to incremental reductions in pHo (from pH 8.0 to pH 6.8) by activating multiple signalling pathways, involving p42/p44, PKB, PKA and calcium mobilization. Coincidently, ASM cells contracted in response to decreased pHo with similar 'dose'-dependence. Real-time PCR suggested OGR1 was the only proton-sensing GPCR expressed in ASM cells. Both acid-induced signalling (with the exception of PKB activation) and contraction were significantly attenuated by knockdown of OGR1. CONCLUSIONS AND IMPLICATIONS: These studies reveal OGR1 to be a physiologically relevant GPCR in ASM cells, capable of pleiotropic signalling and mediating contraction in response to small reductions in extracellular pH. Accordingly, ASM OGR1 may contribute to asthma pathology and represent a therapeutic target in obstructive lung diseases.


Assuntos
Líquido Extracelular/química , Contração Muscular/efeitos dos fármacos , Músculo Liso/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Transdução de Sinais/fisiologia , Brônquios/citologia , Brônquios/efeitos dos fármacos , Técnicas de Cultura de Células , Células Cultivadas , AMP Cíclico/metabolismo , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Humanos , Ácido Clorídrico/farmacologia , Concentração de Íons de Hidrogênio , Indometacina/farmacologia , Músculo Liso/citologia , Músculo Liso/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Traqueia/citologia , Traqueia/efeitos dos fármacos
6.
Ann Thorac Surg ; 70(5): 1675-8, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11093509

RESUMO

BACKGROUND: Lung transplantation for patients on ventilators is a controversial use of scarce donor lungs. We have performed 500 lung transplants in 12 years and 21 of these have been in ventilator-dependent patients. METHODS: A retrospective review of patient records and computerized database was performed. Living patients were contacted to confirm their health and functional status. RESULTS: Patients included 13 men and 8 women with a mean age of 43 years. Sixteen patients were considered stable awaiting lung transplant, whereas 5 patients were unstable with acute graft failure after prior lung transplantation. Stable patients had been ventilated for a mean of 57 +/- 46 days whereas unstable patients had been supported for 10 +/- 9 days. Half of the patients required cardiopulmonary bypass support during the transplant, and there was no statistical difference in the frequency of CPB in stable and unstable patients (p = 0.61). Three hospital deaths included 0 of 16 of the stable patients and 3 of 5 of the unstable patients (p = 0.01). Long-term actuarial survival was significantly better in stable versus unstable patients (p = 0.02), with 5-year survival 40% for stable patients and 0% for unstable patients. CONCLUSIONS: Lung transplantation can be successfully conducted in stable patients who have become ventilator dependent after listing for transplantation. Acute retransplantation for early lung dysfunction is high risk and has produced poor long-term results.


Assuntos
Transplante de Pulmão , Ventiladores Mecânicos , Adulto , Ponte Cardiopulmonar , Feminino , Rejeição de Enxerto , Humanos , Transplante de Pulmão/mortalidade , Masculino , Pessoa de Meia-Idade , Cuidados Pós-Operatórios , Reoperação , Estudos Retrospectivos , Taxa de Sobrevida , Fatores de Tempo
7.
J Thorac Cardiovasc Surg ; 120(5): 909-15, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11044317

RESUMO

OBJECTIVE: Clinical lung transplantation has been limited by availability of suitable cadaveric donor lungs. Living donor lobectomy provides right and left lower lobes from a pair of living donors for each recipient. We reviewed our experience with living donor lobectomy from July 1994 to February 2000. METHODS: Sixty-two donor lobectomies were performed. The hospital and outpatient records of these 62 donors were retrospectively analyzed to examine the incidence of perioperative complications. RESULTS: Twenty-four (38.7%) of 62 donors had no perioperative complications and had a median length of hospital stay of 5.0 days. Thirty-eight (61.3%) of 62 donors had postoperative complications. Twelve major complications occurred in 10 patients and included pleural effusions necessitating drainage (n = 4), bronchial stump fistulas (n = 3), bilobectomy (n = 1), hemorrhage necessitating red cell transfusion (n = 1), phrenic nerve injury (n = 1), atrial flutter ultimately necessitating electrophysiologic ablation (n = 1), and bronchial stricture necessitating dilatation (n = 1). These 38 donors had 55 minor complications including persistent air leaks (n = 9), pericarditis (n = 9), pneumonia (n = 8), arrhythmia (n = 7), transient hypotension necessitating fluid resuscitation (n = 4), atelectasis (n = 3), ileus (n = 3), subcutaneous emphysema (n = 3), urinary tract infections (n = 2), loculated pleural effusions (n = 2), transfusion (n = 2), Clostridium difficile colitis (n = 1), puncture of a saline breast implant (n = 1), and severe contact dermatitis secondary to adhesive tape (n = 1). There were no postoperative deaths and only 1 donor required surgical re-exploration. CONCLUSIONS: Living donor lobectomy can be performed with low mortality and remains an important alternative for potential recipients unable to wait for cadaveric lung allografts. However, morbidity is high and must be considered when potential living donors are being counseled.


Assuntos
Doadores Vivos , Transplante de Pulmão/métodos , Complicações Pós-Operatórias/etiologia , Feminino , Humanos , Incidência , Tempo de Internação/estatística & dados numéricos , Masculino , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento
8.
J Surg Res ; 69(2): 249-54, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9224390

RESUMO

We developed 9H1.B11, an anti-idiotypic anti-deep core/lipid A (DCLA), murine monoclonal antibody (mAb) that mimics the conserved DCLA region of lipopolysaccharide (LPS). It recognizes an epitope in the variable region of an DCLA mAb, binds to the murine macrophage cell surface, and inhibits LPS-induced macrophage cytokine secretion. We hypothesized that (1) active immunization with mAb 9H1.B11 would be associated with the development of anti-DCLA antibodies and (2) immunization would protect against subsequent gram negative bacterial challenge. Mice were immunized for 8 weeks before intraperitoneal (ip) challenge with Escherichia coli O111:B4 bacteria. Control animals were immunized with an irrelevant IgM antibody 8133 (negative control) or with LPS derived from Salmonella minnesota Re bacteria (positive control). Sera from immunized mice were collected, and titers against the core region of LPS (Re) and against LPS derived from the infecting E. coli strain were determined. Mice immunized with mAb 9H1.B11 developed measurable titers against S. minnesota Re LPS but not against the challenge strain of E. coli. However, immunization with 9H1.B11 on S. minnesota Re LPS protected against subsequent infection due to E. coli O111:B4 (100% survival). The group of mice immunized with IgM 8133 exhibited only 25% survival. The development of an anti-S. minnesota Re LPS titer after immunization with 9H1.B11 provides further evidence that a portion of 9H1.B11 mimics the conserved DCLA region of LPS. We believe that this approach holds considerable promise and plan further studies to define the mechanism by which protective capacity occurs.


Assuntos
Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Infecções por Escherichia coli/prevenção & controle , Bactérias Gram-Negativas/imunologia , Lipídeo A/imunologia , Lipopolissacarídeos/imunologia , Sepse/prevenção & controle , Animais , Mapeamento de Epitopos , Infecções por Escherichia coli/imunologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C
9.
J Surg Res ; 63(1): 44-8, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8661170

RESUMO

Twenty-seven amino acid peptides with sequences corresponding to a proposed endotoxin binding region of bactericidal permeability increasing protein (BPI):1) inhibit lipopolysaccharide induced macrophage tumor necrosis factor-alpha (TNF-alpha) secretion, 2) have bactericidal activity against gram-negative bacteria, and 3) protect mice from a lethal lipopolysaccharide (LPS) challenge. Unfortunately, peptides have a short halflife in vivo. Therefore, we have chemically conjugated the BPI based peptide, BG38, to a larger carrier protein, keyhole limpet hemocyanin (KLH), and characterized its ability: 1) to inhibit LPS induced macrophage TNF-alpha secretion and 2) to decrease plasma endotoxin and TNF-alpha levels following an i.v. injection of E. coli 0111:B4 LPS. BG38-KLH inhibited cultured macrophage TNF-alpha secretion in response to LPS derived from four pathogenic strains of gram-negative bacteria in a dose dependent manner (>90% inhibition at 50 microgram/ml, P < 0.05 Student's t test). BG38-KLH also decreased serum endotoxin (>90%, P < 0.05 Student's t test) and peak TNF-alpha levels (>30% inhibition, P < 0.05 Student's t test) following E. coli LPS challenge in a murine gram-negative bacterial sepsis model. Novel endotoxin antagonists based upon a small domain of BPI represent promising reagents for the treatment of serious gram-negative bacterial infections.


Assuntos
Proteínas Sanguíneas/farmacologia , Endotoxinas/farmacologia , Bactérias Gram-Negativas , Lipopolissacarídeos/farmacologia , Macrófagos/fisiologia , Proteínas de Membrana , Fragmentos de Peptídeos/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Animais , Peptídeos Catiônicos Antimicrobianos , Atividade Bactericida do Sangue , Proteínas Sanguíneas/química , Linhagem Celular , Endotoxinas/antagonistas & inibidores , Escherichia coli , Humanos , Klebsiella pneumoniae , Lipopolissacarídeos/antagonistas & inibidores , Macrófagos/efeitos dos fármacos , Camundongos , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Pseudomonas aeruginosa , Serratia marcescens
10.
J Surg Res ; 58(6): 739-45, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7791354

RESUMO

Although lymphocyte-derived cytokines are known to augment macrophage cytokine production in vitro, their effect on macrophage tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) secretion during gram-negative bacterial sepsis has not been characterized. The purpose of this study was to examine the effect of lymphocyte-derived cytokines on macrophage TNF-alpha and IL-6 secretion during gram-negative bacterial peritonitis. To examine this problem, uninfected and infected mice were studied. Mice were infected with Escherichia coli O111:B4 and two subgroups were examined consisting of those pretreated iv 1 hr prior to bacterial challenge with either (1) saline or (2) anti-E. coli O111:B4 LPS mAb 2A3, the latter administered to abrogate the effects of LPS in vivo. Thus, three groups of mice were studied in relation to pretreatment and infectious challenges: (1) saline/saline (control); (2) saline/E. coli (saline); and (3) mAb 2A3/E. coli (mAb 2A3). Nonadherent splenocytes (> 95% lymphocytes by histologic staining criteria) harvested 16 hr later from mice in each group were incubated in culture ex vivo for 3 hr to obtain supernatants containing lymphocyte-derived cytokines. These supernatants containing lymphocyte-derived cytokines then were incubated in vitro with naive splenic macrophages with or without E. coli O111:B4 LPS. Macrophage TNF-alpha and IL-6 levels were determined using L929 and B9 bioassays.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Citocinas/farmacologia , Infecções por Bactérias Gram-Negativas/metabolismo , Interleucina-6/metabolismo , Macrófagos/metabolismo , Sepse/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Células Cultivadas , Lipopolissacarídeos/farmacologia , Linfócitos/fisiologia , Camundongos , Camundongos Endogâmicos BALB C
11.
Arch Surg ; 129(2): 179-80, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8304828

RESUMO

OBJECTIVE: This study tried to determine whether administration of antilipopolysaccharide (LPS) murine monoclonal antibody (mAb) 2A3 to mice was associated with (1) protective capacity during experimental gram-negative bacterial sepsis, and (2) inhibition of tumor necrosis factor alpha (TNF-alpha) secretion in the systemic circulation and at the tissue level during experimental infection. DESIGN: Mice received an initial intravenous injection of either saline or 100 micrograms of anti-LPS mAb 2A3, and 1 hour later underwent intraperitoneal inoculation of viable Escherichia coli 0111:B4. Mortality was assessed daily for 7 days. Separate groups of mice were treated similarly and plasma TNF-alpha concentrations were determined from blood samples obtained at 1, 3, 6, 10, and 16 hours after infection by enzyme-linked immunosorbent assay. Concurrently, splenocytes harvested from animals 3, 10, and 16 hours after infection were incubated in culture ex vivo and supernatant TNF-alpha levels were determined. RESULTS: Pretreatment with anti-LPS mAb 2A3 prior to an intraperitoneal challenge of live E coli 0111:B4 was associated with the following: (1) significant protective capacity (100% vs 0% mortality, P < .001); (2) inhibition of plasma TNF-alpha levels 16 hours after infection (1257 +/- 323 pg/mL vs 292 +/- 254 pg/mL, P < .001); and (3) abrogation of TNF-alpha secretion derived from splenic macrophages isolated 16 hours after bacterial challenge (229 +/- 12 pg/mL vs 107 +/- 48 pg/mL, P < .05). CONCLUSIONS: These results strongly support the contention that inhibition of LPS-induced TNF-alpha secretion at both the tissue and systemic levels is a key mechanism by which anti-LPS mAbs provide protection during gram-negative bacterial peritonitis. We believe that in vivo monitoring of macrophage cytokine secretion will be critical for elucidating the precise role of a variety of mediators in the pathogenesis of gram-negative bacterial sepsis.


Assuntos
Anticorpos Monoclonais/imunologia , Infecções por Escherichia coli/imunologia , Escherichia coli , Lipopolissacarídeos/imunologia , Macrófagos/imunologia , Peritonite/microbiologia , Baço/patologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Sobrevivência Celular , Infecções por Escherichia coli/sangue , Camundongos , Camundongos Endogâmicos BALB C , Peritonite/sangue , Peritonite/imunologia , RNA Mensageiro/biossíntese , Taxa de Sobrevida , Fator de Necrose Tumoral alfa/análise , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
13.
Ann Surg ; 218(3): 250-9; discussion 259-61, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8373268

RESUMO

OBJECTIVE: To determine whether monoclonal antibodies (mAbs) directed against lipopolysaccharide (LPS, endotoxin) act by promoting LPS neutralization, LPS uptake by macrophages, or both processes, the authors assessed the effects of these agents on LPS-induced cytokine secretion and cellular uptake of LPS. SUMMARY BACKGROUND DATA: MAbs directed against LPS have been shown to attenuate LPS-induced macrophage tumor necrosis factor-alpha (TNF-alpha) secretion, a process that may contribute to protective capacity. The mechanisms by which this process occurs have not been established. METHODS: MAbs directed against LPS were evaluated in vitro for their capacity to (1) inhibit TNF-alpha secretion, and (2) alter fluorescein isothiocyanate-labeled LPS uptake (employing flow cytometry analysis and fluorescence microscopy) by the macrophage-like cell line RAW 264.7. RESULTS: MAb 8G9, an IgG3 directed against the O-antigen polysaccharide region of Escherichia coli 0111:B4 LPS, significantly reduced LPS-induced TNF-alpha secretion and promoted a more than 40-fold increase in LPS uptake by macrophages. The authors established that this was mediated by a Fc receptor-mediated process because 8G9 F(ab')2 fragments that lack the Fc portion of the IgG molecule were capable of inhibiting TNF-alpha secretion, but did not promote increased LPS uptake to the same degree. Cross-reactive, anti-deep core/lipid A mAb 1B6, an IgG2a, also promoted uptake of E. coli 0111:B4 LPS and O-antigen polysaccharide-deficient E. coli J5 LPS, but only inhibited TNF-alpha secretion induced by E. coli J5 LPS to which it binds most efficiently. MAb 3D10, an IgM also directed against the O-antigen polysaccharide region of E. coli 0111:B4 LPS, inhibited TNF-alpha secretion but did not increase cellular uptake of LPS, presumably acting solely due to LPS neutralization. Polymyxin B, an antibiotic that binds stoichiometrically to the lipid A portion of LPS, inhibited TNF-alpha secretion and prevented cellular LPS uptake. CONCLUSIONS: These results suggest that IgG and IgM anti-LPS mAbs exert protective capacity by extracellular neutralization of LPS, while IgG Fc receptor-mediated cellular uptake also may serve to bypass macrophage activation and TNF-alpha secretion by promoting internalization and intracellular neutralization.


Assuntos
Endotoxinas/antagonistas & inibidores , Imunoglobulinas/farmacologia , Lipopolissacarídeos/metabolismo , Macrófagos/metabolismo , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Animais , Anticorpos Monoclonais/farmacologia , Células Cultivadas , Endotoxinas/imunologia , Citometria de Fluxo , Imunoglobulina G/imunologia , Lipopolissacarídeos/imunologia , Macrófagos/imunologia , Camundongos , Microscopia de Fluorescência , Polimixina B/farmacologia , Receptores Fc/imunologia , Fator de Necrose Tumoral alfa/metabolismo
14.
J Surg Res ; 54(4): 342-8, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8331928

RESUMO

Gram-negative bacterial lipopolysaccharide (LPS, endotoxin) directly stimulates macrophages to produce tumor necrosis factor (TNF). TNF, in turn, produces a constellation of adverse effects that includes hypotension, systemic acidosis, arterial hypoxemia, and death. Transcription of the TNF gene occurs within minutes of LPS stimulation and appears to be a critical control point in the synthesis and secretion of TNF protein by macrophages. We hypothesized that murine monoclonal antibody (mAb) 8G9 directed against Escherichia coli 0111:B4 LPS would provide protective capacity against an E. coli 0111:B4 bacterial challenge in vivo and would concurrently inhibit LPS-induced synthesis of TNF mRNA and secretion of TNF protein in vitro. E. coli 0111:B4 LPS was used to stimulate a macrophage-derived cell line (RAW 264.7) to produce TNF in the presence or absence of mAb 8G9. Media alone and LPS without 8G9 mAb served as controls against which the effect of 8G9 mAb was compared. Total cellular RNA was purified and analyzed by a Northern blotting technique utilizing a radiolabeled cDNA probe specific for TNF mRNA. TNF mRNA levels from each sample were quantitated by autoradiograph densitometry. Pretreatment with mAb 8G9 provided protective capacity against an intraperitoneal E. coli 0111:B4 bacterial challenge in vivo when compared with saline pretreatment alone (22% versus 90% mortality respectively, P < 0.05). Preincubation of LPS with mAb 8G9 resulted in a significant inhibition of LPS-induced TNF mRNA synthesis (63 +/- 20%, P < 0.01) and TNF protein secretion (88 +/- 10%, P < 0.001) in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Anticorpos Monoclonais/imunologia , Lipopolissacarídeos/imunologia , Macrófagos/metabolismo , RNA Mensageiro/antagonistas & inibidores , Fator de Necrose Tumoral alfa/genética , Animais , Linhagem Celular , RNA Mensageiro/biossíntese
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