RESUMO
The Nijmegen breakage syndrome 1 (Nbs1) subunit of the Mre11-Rad50-Nbs1 (MRN) complex protects genome integrity by coordinating double-strand break (DSB) repair and checkpoint signaling through undefined interactions with ATM, MDC1, and Sae2/Ctp1/CtIP. Here, fission yeast and human Nbs1 structures defined by X-ray crystallography and small angle X-ray scattering (SAXS) reveal Nbs1 cardinal features: fused, extended, FHA-BRCT(1)-BRCT(2) domains flexibly linked to C-terminal Mre11- and ATM-binding motifs. Genetic, biochemical, and structural analyses of an Nbs1-Ctp1 complex show Nbs1 recruits phosphorylated Ctp1 to DSBs via binding of the Nbs1 FHA domain to a Ctp1 pThr-Asp motif. Nbs1 structures further identify an extensive FHA-BRCT interface, a bipartite MDC1-binding scaffold, an extended conformational switch, and the molecular consequences associated with cancer predisposing Nijmegen breakage syndrome mutations. Tethering of Ctp1 to a flexible Nbs1 arm suggests a mechanism for restricting DNA end processing and homologous recombination activities of Sae2/Ctp1/CtIP to the immediate vicinity of DSBs.
Assuntos
Proteínas de Ciclo Celular/química , Proteínas Cromossômicas não Histona/química , Reparo do DNA , Proteínas Nucleares/química , Proteínas de Schizosaccharomyces pombe/química , Hidrolases Anidrido Ácido , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Cristalografia por Raios X , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteína Homóloga a MRE11 , Modelos Moleculares , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Estrutura Terciária de Proteína , Espalhamento a Baixo Ângulo , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMO
Acute moderate- to high-intensity exercise, primarily aerobic exercise, has been reported to decrease food reward in brain regions via the hedonic pathways and reduce preference for high-energy or high-fat foods. However, studies examining food reward responses to acute exercise have been limited to measuring food reward only after exercise and less frequently before and after exercise. Therefore, the changes in food reward in response to acute exercise remain unclear. This study investigated the effect of acute running on food reward in healthy young men. Fourteen young healthy men (mean ± standard deviation, age; 23 ± 2 years, body mass index; 21 ± 2 kg/m2) completed two trials (i.e., exercise and control) in a randomised, crossover design. Participants performed a 30-min running bout at 70% of maximal oxygen uptake or sitting rest before and after food reward evaluation with a computer-based food choice behaviour task tool. Food reward was assessed for foods varying in fat content and sweet taste, and there were four assessment parameters: explicit liking, explicit wanting, implicit wanting and frequency of choice of each food category (relative preference). Explicit and implicit wanting, and relative preference for high-fat relative to low-fat foods were reduced after the exercise trial compared to the control trial (trial-by-time interaction, all p ≤ 0.02). Implicit wanting and relative preference for sweet relative to savoury foods were increased after the exercise trial compared to the control trial (trial-by-time interaction, all p ≤ 0.003). These findings indicate that moderate-intensity acute running alters the reward bias away from high fat towards low fat foods and away from savoury towards sweet foods in healthy young men.
Assuntos
Estudos Cross-Over , Gorduras na Dieta , Preferências Alimentares , Recompensa , Corrida , Humanos , Masculino , Adulto Jovem , Preferências Alimentares/psicologia , Adulto , Gorduras na Dieta/administração & dosagem , Corrida/fisiologia , Corrida/psicologia , Paladar/fisiologia , Comportamento de Escolha , Exercício Físico/psicologia , Índice de Massa CorporalRESUMO
BACKGROUND: Trabectedin binds covalently to the DNA minor groove and causes DNA to bend toward the main groove, then trabectedin regulates the transcription of the involved genes in cell proliferation or acts on the mononuclear phagocyte system in tumors, which contributes to its antitumor effects. Several clinical trials confirmed the efficacy of trabectedin for patients with advanced soft tissue sarcoma (STS) although clinically useful biomarkers remained unidentified. This study aimed to identify prognostic factors of trabectedin treatment, especially focusing on the systemic inflammatory, immune response, and nutritional status. METHODS: This study included 44 patients with advanced STS treated with trabectedin from January 2018 to August 2022. We evaluated the associations of clinical factors that influence the efficacy of trabectedin treatment with progression-free survival (PFS) and overall survival (OS), focusing on systemic inflammatory, immune response, and nutritional status represented by the absolute lymphocyte count (ALC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), systemic inflammation response index (SIRI), prognostic nutrition index (PNI), and C-reactive protein (CRP) using the Kaplan-Meier method and the log-rank test. RESULTS: ALC, LMR, PNI, NLR, PLR, and SIRI demonstrated no association with PFS. Patients with CRP of ≥0.3 had a significantly shorter PFS than those with CRP of <0.3 (median PFS: 863 vs. 105 days, P = 0.045). PNI of ≥44 (median: 757 days vs. 232 days, P = 0.021) and CRP of <0.3 (median: 877 days vs. 297 days, P = 0.043) were significantly good prognostic factors in terms of OS. CONCLUSIONS: The study results indicate pretreatment PNI and CRP levels as prognostic factors for trabectedin treatment in advanced STS.
RESUMO
Mre11 forms the core of the multifunctional Mre11-Rad50-Nbs1 (MRN) complex that detects DNA double-strand breaks (DSBs), activates the ATM checkpoint kinase, and initiates homologous recombination (HR) repair of DSBs. To define the roles of Mre11 in both DNA bridging and nucleolytic processing during initiation of DSB repair, we combined small-angle X-ray scattering (SAXS) and crystal structures of Pyrococcus furiosus Mre11 dimers bound to DNA with mutational analyses of fission yeast Mre11. The Mre11 dimer adopts a four-lobed U-shaped structure that is critical for proper MRN complex assembly and for binding and aligning DNA ends. Further, mutations blocking Mre11 endonuclease activity impair cell survival after DSB induction without compromising MRN complex assembly or Mre11-dependant recruitment of Ctp1, an HR factor, to DSBs. These results show how Mre11 dimerization and nuclease activities initiate repair of DSBs and collapsed replication forks, as well as provide a molecular foundation for understanding cancer-causing Mre11 mutations in ataxia telangiectasia-like disorder (ATLD).
Assuntos
Proteínas Arqueais/metabolismo , Reparo do DNA , DNA/metabolismo , Endodesoxirribonucleases/metabolismo , Exodesoxirribonucleases/metabolismo , Pyrococcus furiosus/química , Proteínas Arqueais/química , Proteínas Arqueais/genética , Cristalografia por Raios X , DNA/química , Quebras de DNA de Cadeia Dupla , Análise Mutacional de DNA , Dimerização , Endodesoxirribonucleases/química , Endodesoxirribonucleases/genética , Exodesoxirribonucleases/química , Exodesoxirribonucleases/genética , Modelos Moleculares , Espalhamento a Baixo Ângulo , Schizosaccharomyces/genética , Técnicas do Sistema de Duplo-Híbrido , Difração de Raios XRESUMO
Few studies have examined the influence of pre-exercise meals with different glycaemic indices (GIs) on substrate oxidation and non-homeostatic appetite (i.e. food reward) in adults of various ages and ethnicities. We aimed to examine the effects of pre-exercise high and low GI meals on substrate oxidation and food reward in middle-aged Japanese women. This randomised crossover trial included fifteen middle-aged women (aged 40â 9 ± 6â 5 years, mean ± sd). The participants consumed a high or low GI breakfast at 09.00 and rested until 11.00. Thereafter, participants performed a 60-min walk at 50 % of their estimated maximum oxygen uptake (11.00-12.00) and rested until 13.00. Expired gas samples were collected every 30 min prior to walking, and samples were collected continuously throughout the walking and post-walking periods. Blood samples and subjective appetite ratings were collected every 30 min, except during walking. The Leeds Food Preference Questionnaire in Japanese (LFPQ-J) was used to assess food reward at 09.00, 10.00, and 13.00 h. The cumulative fat oxidation during exercise was higher in the low GI trial than in the high GI trial (P = 0â 03). The cumulative carbohydrate oxidation during walking was lower in the low GI trial than in the high GI trial (P = 0â 01). Trial-by-time interactions were not found for any food-reward parameters between trials. Low GI meals elicited enhanced fat oxidation during a subsequent 60-min walk in middle-aged women. However, meals with different GIs did not affect food reward evaluated over time in the present study.
Assuntos
Apetite , Índice Glicêmico , Adulto , Pessoa de Meia-Idade , Humanos , Feminino , Glicemia/metabolismo , Consumo de Oxigênio , Carboidratos da Dieta/metabolismo , Oxigênio , RefeiçõesRESUMO
Recombination is essential for the recovery of stalled/collapsed replication forks and therefore for the maintenance of genomic stability. The situation becomes critical when the replication fork collides with an unrepaired single-strand break and converts it into a one-ended double-strand break. We show in fission yeast that a unique broken replication fork requires the homologous recombination (HR) enzymes for cell viability. Two structure-specific heterodimeric endonucleases participate in two different resolution pathways. Mus81/Eme1 is essential when the sister chromatid is used for repair; conversely, Swi9/Swi10 is essential when an ectopic sequence is used for repair. Consequently, the utilization of these two HR modes of resolution mainly relies on the ratio of unique and repeated sequences present in various eukaryotic genomes. We also provide molecular evidence for sister recombination intermediates. These findings demonstrate that Mus81/Eme1 is the dedicated endonuclease that resolves sister chromatid recombination intermediates during the repair of broken replication forks.
Assuntos
Cromátides/genética , Replicação do DNA/fisiologia , Proteínas de Ligação a DNA/fisiologia , Endonucleases/fisiologia , Recombinação Genética , Proteínas de Schizosaccharomyces pombe/fisiologia , Imunoprecipitação da Cromatina , DNA Helicases/genética , DNA Helicases/metabolismo , DNA Helicases/fisiologia , Replicação do DNA/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel Bidimensional , Endonucleases/genética , Endonucleases/metabolismo , Modelos Genéticos , Fenótipo , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Rad51 Recombinase/fisiologia , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Schizosaccharomyces/fisiologia , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMO
The Mre11-Rad50-Nbs1 (MRN) protein complex and ATM/Tel1 kinase protect genome integrity through their functions in DNA double-strand break (DSB) repair, checkpoint signaling, and telomere maintenance. Nbs1 has a conserved C-terminal motif that binds ATM/Tel1, but the full extent and significance of ATM/Tel1 interactions with MRN are unknown. Here, we show that Tel1 overexpression bypasses the requirement for Nbs1 in DNA damage signaling and telomere maintenance. These activities require Mre11-Rad50, which localizes to DSBs and bind Tel1 in the absence of Nbs1. Fusion of the Tel1-binding motif of Nbs1 to Mre11 is sufficient to restore Tel1 signaling in nbs1Δ cells. Tel1 overexpression does not restore Tel1 signaling in cells carrying the rad50-I1192W mutation, which impairs the ability of Mre11-Rad50 to form the ATP-bound closed conformation. From these findings, we propose that Tel1 has a high-affinity interaction with the C-terminus of Nbs1 and a low-affinity association with Mre11-Rad50, which together accomplish efficient localization and activation of Tel1 at DSBs and telomeres.
Assuntos
Quebras de DNA de Cadeia Dupla , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Telômero/metabolismo , Trifosfato de Adenosina/metabolismo , Mutação/genética , Ligação Proteica , Proteínas de Schizosaccharomyces pombe/química , Transdução de SinaisRESUMO
We have been investigating the functional display of multipass membrane protein such as transporter or G-protein coupled receptor on the budded baculovirus (BV). We tested the use of a viral envelope protein gp64 transgenic mouse for the direct immunization of these membrane proteins displayed on BVs. The gp64 transgenic mice showed only a weak response to virus compared to wild type BALB/c mice. Immunizing gp64 transgenic mice with the BV expressing peptide transporter PepT1, we obtained 47 monoclonal antibodies (mAbs). These mAbs were specific to the PepT1 on the pancreatic cancer cells AsPC-1 by fluorocytometric analysis and exhibited antibody-dependent cellular cytotoxicity or complement-dependent cytotoxicity to AsPC-1. We also generated 7 mAbs by immunizing gp64 transgenic mice on a CCR2-deficient background with the BV expressing chemokine receptor CCR2 together with partially purified CCR2. These mAbs possessed specific binding to CCR2 in CHO cells on fluorocytometric analysis, and exhibited neutralizing activities for ligand-dependent inhibition of cyclic AMP production. This method provides a powerful tool for the generation of therapeutic/diagnostic mAbs against membrane proteins.
Assuntos
Anticorpos Monoclonais/biossíntese , Baculoviridae/genética , Moléculas de Adesão Celular/genética , Glicoproteínas de Membrana/genética , Proteínas de Membrana/imunologia , Biblioteca de Peptídeos , Proteínas do Envelope Viral/genética , Proteínas Virais/genética , Animais , Baculoviridae/metabolismo , Células CHO , Linhagem Celular Tumoral , Cricetinae , Cricetulus , Imunização , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Transportador 1 de Peptídeos , Receptores CCR2 , Receptores de Quimiocinas/imunologia , Simportadores/imunologia , Proteínas do Envelope Viral/imunologiaRESUMO
Assembly of initiation factors on individual replication origins at onset of S phase is crucial for regulation of replication timing and repression of initiation by S-phase checkpoint control. We dissected the process of preinitiation complex formation using a point mutation in fission yeast nda4-108/mcm5 that shows tight genetic interactions with sna41(+)/cdc45(+). The mutation does not affect loading of MCM complex onto origins, but impairs Cdc45-loading, presumably because of a defect in interaction of MCM with Cdc45. In the mcm5 mutant, however, Sld3, which is required for Cdc45-loading, proficiently associates with origins. Origin-association of Sld3 without Cdc45 is also observed in the sna41/cdc45 mutant. These results suggest that Sld3-loading is independent of Cdc45-loading, which is different from those observed in budding yeast. Interestingly, returning the arrested mcm5 cells to the permissive temperature results in immediate loading of Cdc45 to the origin and resumption of DNA replication. These results suggest that the complex containing MCM and Sld3 is an intermediate for initiation of DNA replication in fission yeast.
Assuntos
Replicação do DNA , Proteínas de Ligação a DNA/fisiologia , Proteínas de Schizosaccharomyces pombe/fisiologia , Schizosaccharomyces/genética , Ciclo Celular/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Proteínas de Ligação a DNA/análise , Proteínas de Ligação a DNA/genética , Componente 6 do Complexo de Manutenção de Minicromossomo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Mutação Puntual/genética , Origem de Replicação/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/análise , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMO
Hybridoma that produces rat anti-mouse interleukin 6 receptor (IL-6R) antibody, MR16-1, was established by the fusion of mouse P3U1 myeloma cells and spleen cells from mouse soluble IL-6R (sIL-6R)-immunized Wistar rat. In the present study, we examined the characteristics of MR16-1 in vitro and in vivo. MR16-1 bound to mouse sIL-6R dose-dependently. MR16-1 suppressed IL-6-induced proliferation of 7TD1 cells in a dose-dependent manner and this inhibitory effect was reversed by the addition of a higher concentration of IL-6. Cross-reactivity study using T cells from mouse, rat, and human revealed that MR16-1 did not cross-react with human and rat IL-6R. Binding region analysis using several human-mouse chimeric IL-6Rs showed that half of the fibronectin domain II of mouse IL-6R (amino acids 214-285) was required for MR16-1 binding. Furthermore, MR16-1 completely suppressed IL-6-induced antibody production in DNP-KLH immunized mice. These lines of evidence demonstrate that MR16-1 is useful to investigate the physiological and pathological roles of IL-6 and sIL-6R in mice.
Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos/imunologia , Receptores de Interleucina-6/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/farmacologia , Formação de Anticorpos/efeitos dos fármacos , Formação de Anticorpos/imunologia , Células COS , Humanos , Hibridomas/efeitos dos fármacos , Hibridomas/imunologia , Interleucina-6/imunologia , Interleucina-6/farmacologia , Camundongos , Dados de Sequência Molecular , Ratos , Receptores de Interleucina-6/antagonistas & inibidores , Especificidade da EspécieRESUMO
The Mre11-Rad50-Nbs1 (MRN) complex is a primary sensor of DNA double-strand breaks (DSBs). Upon recruitment to DSBs, it plays a critical role in catalyzing 5' --> 3' single-strand resection that is required for repair by homologous recombination (HR). Unknown mechanisms repress HR in G1 phase of the cell cycle during which nonhomologous end-joining (NHEJ) is the favored mode of DSB repair. Here we describe fission yeast Ctp1, so-named because it shares conserved domains with the mammalian tumor suppressor CtIP. Ctp1 is recruited to DSBs where it is essential for repair by HR. Ctp1 is required for efficient formation of RPA-coated single-strand DNA adjacent to DSBs, indicating that it functions with the MRN complex in 5' --> 3' resection. Transcription of ctp1(+) is periodic during the cell cycle, with the onset of its expression coinciding with the start of DNA replication. These data suggest that regulation of Ctp1 underlies cell-cycle control of HR.
Assuntos
Ciclo Celular/fisiologia , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Recombinação Genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/fisiologia , Sequência de Aminoácidos , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/genética , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Humanos , Dados de Sequência Molecular , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Schizosaccharomyces/citologia , Proteínas de Schizosaccharomyces pombe/genética , Alinhamento de Sequência , Telômero/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-HíbridoRESUMO
DNA replication of eukaryotic chromosomes initiates at a number of discrete loci, called replication origins. Distribution and regulation of origins are important for complete duplication of the genome. Here, we determined locations of Orc1 and Mcm6, components of pre-replicative complex (pre-RC), on the whole genome of Schizosaccharomyces pombe using a high-resolution tiling array. Pre-RC sites were identified in 460 intergenic regions, where Orc1 and Mcm6 colocalized. By mapping of 5-bromo-2'-deoxyuridine (BrdU)-incorporated DNA in the presence of hydroxyurea (HU), 307 pre-RC sites were identified as early-firing origins. In contrast, 153 pre-RC sites without BrdU incorporation were considered to be late and/or inefficient origins. Inactivation of replication checkpoint by Cds1 deletion resulted in BrdU incorporation with HU specifically at the late origins. Early and late origins tend to distribute separately in large chromosome regions. Interestingly, pericentromeric heterochromatin and the silent mating-type locus replicated in the presence of HU, whereas the inner centromere or subtelomeric heterochromatin did not. Notably, MCM did not bind to inner centromeres where origin recognition complex was located. Thus, replication is differentially regulated in chromosome domains.
Assuntos
Replicação do DNA/genética , Genoma Fúngico , Origem de Replicação/genética , Schizosaccharomyces/genética , Ciclo Celular/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Centrômero/metabolismo , Quinase do Ponto de Checagem 2 , Cromossomos Fúngicos , Replicação do DNA/efeitos dos fármacos , DNA Intergênico/genética , Didesoxinucleosídeos/metabolismo , Eletroforese em Gel Bidimensional , Heterocromatina/metabolismo , Hidroxiureia/farmacologia , Componente 6 do Complexo de Manutenção de Minicromossomo , Análise de Sequência com Séries de Oligonucleotídeos , Complexo de Reconhecimento de Origem/genética , Complexo de Reconhecimento de Origem/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Schizosaccharomyces/efeitos dos fármacos , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismoRESUMO
Initiation of chromosome DNA replication in eukaryotes is tightly regulated through assembly of replication factors at replication origins. Here, we investigated dependence of the assembly of the initiation complex on particular factors using temperature-sensitive fission yeast mutants. The psf3-1 mutant, a GINS component mutant, arrested with unreplicated DNA at the restrictive temperature and the DNA content gradually increased, suggesting a defect in DNA replication. The mutation impaired GINS complex formation, as shown by pull-down experiments. Chromatin immunoprecipitation assays indicated that GINS integrity was required for origin loading of Psf2, Cut5 and Cdc45, but not Sld3. In contrast, loading of Psf2 onto origins depended on Sld3 and Cut5 but not on Cdc45. These results suggest that Sld3 functions furthest upstream in initiation complex assembly, followed by GINS and Cut5, then Cdc45. Consistent with this conclusion, Cdc7-Dbf4 kinase (DDK) but not cyclin-dependent kinase (CDK) was required for Sld3 loading, whereas recruitment of the other factors depended on both kinases. These results suggest that DDK and CDK regulate distinct steps in activation of replication origins in fission yeast.
Assuntos
Quinases Ciclina-Dependentes/metabolismo , Proteínas de Ligação a DNA/metabolismo , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Origem de Replicação/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cromossomos Fúngicos/genética , Modelos Genéticos , Mutação/genética , Transporte Proteico , Fase S , Schizosaccharomyces/citologiaRESUMO
Transgenic mice carrying human IL-6 cDNA fused with a murine major histocompatibility class-I promoter (H-2L(d)) were serially administered with anti-interleukin-6 receptor (IL-6R) monoclonal antibody (mAb), MR16-1, from the age of 4 weeks to estimate its efficacy on a variety of disorders developed in these mice, most of which are similar to the disorders associated with Castleman's disease. In the control mice treated with isotype-matched mAb, a massive and multiple IgG1 plasmacytosis, mesangial proliferative glomerulonephritis, leukocytosis, thrombocytosis, anemia and abnormalities of blood chemical parameters have developed in accordance with the elevation of serum IL-6, and 50% of mice have died of renal failure by 18 weeks of age. In contrast, the treatment with MR16-1 prevented all these symptoms and prolonged the lifetime of the majority of the mice. Thus, the constitutive overexpression of IL-6 caused various disorders, and the treatment with anti-IL-6R mAb completely prevented from these symptoms. These results clearly confirm that IL-6 indeed plays an essential role in the pathogenesis of a variety of disorders. Furthermore, anti-IL-6R mAb could provide novel therapy for Castleman's disease and MR16-1 should be a useful tool to estimate therapeutic potential of IL-6 antagonists in a variety of murine models for human disease.