An Anti-HER2 Monoclonal Antibody H2Mab-41 Exerts Antitumor Activities in Mouse Xenograft Model Using Dog HER2-Overexpressed Cells

Overexpression of human epidermal growth factor receptor 2 (HER2) has been reported in a variety of cancer types, including breast, lung, gastric, pancreatic, and colorectal cancers. Trastuzumab, a humanized anti-HER2 monoclonal antibody (mAb), has been shown to provide significant survival benefits in HER2-overexpressing breast cancer and gastric cancer patients. Previously, an anti-HER2 mAb, H₂Mab-41 (IgG_2b, kappa), was developed in our laboratory and its antitumor activity was demonstrated in mouse xenograft models of human colon cancer. The present study aimed to investigate the ability of H₂Mab-41 to induce antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in dog HER2 (dHER2)-overexpressed cell lines, and thus exert its antitumor activity against dHER2-overexpressed tumors in vivo. Flow cytometry results demonstrated the cross-reactivity of H₂Mab-41 with dHER2. Further evaluation of interaction between H₂Mab-41 and dHER2-overexpressed CHO-K1 (CHO/dHER2) cells indicated moderate binding affinity of H₂Mab-41 toward dHER2, with a dissociation constant (K_D) of 2.6 × 10^-8 M. In vitro analysis revealed that the administration of H₂Mab-41 induced high levels of ADCC and CDC in CHO/dHER2 cells. Furthermore, intraperitoneal administration of H₂Mab-41 in mouse xenograft models of CHO/dHER2 resulted in significant inhibition of tumor development compared to the control mouse IgG. Thus, the findings of the present study demonstrated the in vivo safety and efficacy of H₂Mab-41, highlighting its suitability to be included as a part of a therapeutic regimen for dHER2-expressing canine cancers.

Development of a Novel Anti-HER2 Monoclonal Antibody H2Mab-181 for Gastric Cancer

Human epidermal growth factor receptor 2 (HER2) is a type I transmembrane 185 kDa protein. HER2 is expressed in a variety of normal tissue types and cancer cells. HER2 is associated with cell proliferation, differentiation, and migration. The overexpression of HER2 has been observed in a number of cancers, including breast and gastric cancers. Gastric cancer is one of the most common cancers worldwide, with an annual case rate of ∼1 million people diagnosed with the disease. Trastuzumab is a humanized anti-HER2 monoclonal antibody (mAb) that has been utilized in gastric cancer therapy. In this study, we have developed a novel anti-HER2 mAb, H₂Mab-181 (IgG₁, kappa), through the immunization of mice with a purified recombinant extracellular domain of HER2. H₂Mab-181 can specifically and sensitively detect HER2 in both flow cytometry and Western blot applications in gastric cancer cell lines and can also be utilized in immunohistochemical analyses of gastric cancer tissues. Together, H₂Mab-181 could be useful for the diagnosis and therapy in gastric cancers.

Development of Core-Fucose-Deficient Humanized and Chimeric Anti-Human Podoplanin Antibodies

Podoplanin (PDPN), a 36-kDa type I transmembrane O-glycoprotein, is expressed in normal cells, including renal epithelial cells (podocytes), lymphatic endothelial cells, and pulmonary type I alveolar cells, and in cancer cells, including brain tumors and squamous cell lung carcinomas. PDPN activates platelet aggregation by binding to C-type lectin-like receptor-2 (CLEC-2) on platelets, and PDPN/CLEC-2 interaction facilitates blood/lymphatic vessel separation. We previously produced an anti-human PDPN monoclonal antibody (mAb), clone NZ-1 (rat IgG_2a, lambda) and its rat-human chimeric mAbs (NZ-8/NZ-12), which neutralize PDPN/CLEC-2 interactions and inhibit platelet aggregation and cancer metastasis. In this study, we first developed a humanized anti-human PDPN mAb, named as NZ-27. We further produced a core-fucose-deficient version of NZ-27, named as P1027 and a core-fucose-deficient version of NZ-12, named as NZ-12f. We investigated the binding affinity, antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and antitumor activity of P1027 and NZ-12f. We demonstrated that the binding affinities of P1027 and NZ-12f against LN319 (a human glioblastoma cell line) are 1.1 × 10^-8 and 3.9 × 10^-9 M, respectively. ADCC reporter assays demonstrated that NZ-12f shows 1.5 times higher luminescence than P1027. Furthermore, NZ-12f showed 2.2 times higher ADCC than P1027, whereas both P1027 and NZ-12f showed high CDC activities against LN319 cells. Using LN319 xenograft models, P1027 and NZ-12f significantly reduced tumor development in an LN319 xenograft model compared with control human IgG. Treatment with P1027 and NZ-12f may be a useful therapy for patients with PDPN-expressing cancers.

Epitope Mapping of the Anti-California Sea Lion Podoplanin Monoclonal Antibody PMab-269 Using Alanine-Scanning Mutagenesis and ELISA

Podoplanin (PDPN) plays a pivotal role in platelet aggregation, embryo development, and tumor progression. PDPN is universally expressed in many mammalian species, and is considered a typical lymphatic endothelial cell marker. We have previously developed the mouse anti-California sea lion (Zalophus californianus) PDPN (seaPDPN) monoclonal antibody (mAb), clone PMab-269, which is suitable for different experimental applications, including flow cytometry, Western blotting, and immunohistochemistry. In this study, we identified the PMab-269 epitope of the seaPDPN by enzyme-linked immunosorbent assay using deletion mutants and point mutants generated for seaPDPN. Our results demonstrated that PMab-269 recognized the peptide, corresponding to the amino acids 63-82 of seaPDPN. Furthermore, the reactions of PMab-269 to seven alanine-substituted peptides, such as P68A, D76A, F77A, H78A, L79A, E80A, and D81A, were abolished among 20 alanine-substituted peptides. We identified the seven amino acids (Pro68, Asp76, Phe77, His78, Leu79, Glu80, and Asp81) as the critical epitope targeted by PMab-269. The successful identification of the PMab-269 epitope might contribute to the pathophysiological investigations of seaPDPN.

Epitope Mapping of the Anti-CD44 Monoclonal Antibody (C44Mab-46) Using the REMAP Method

CD44 functions as a major hyaluronan receptor on most cell types, with roles in cell adhesion, migration, proliferation, differentiation, and survival. The CD44 gene comprises 20 exons, with alternative splicing producing many different isoforms. CD44 variant isoforms exhibit tissue-specific expression patterns and have been studied as therapeutic targets for several cancers; therefore, anti-CD44 monoclonal antibodies (mAbs) are useful for investigating CD44 expression in various cancers. Previously, we established an anti-CD44 mAb, C₄₄Mab-46 (IgG₁, κ), by immunizing mice with the CD44v3-10 ectodomain. Although C₄₄Mab-46 recognized all CD44 isoforms, the binding epitope of C₄₄Mab-46 has not been determined. In this study, we first checked the reactivity of C₄₄Mab-46 to several CD44v3-10 deletion mutants such as dN79, dN124, dN147, and dN224. We found the N-terminus of the C₄₄Mab-46-binding epitope between residues 147 and 224 of CD44v3-10. We next investigated this epitope using a novel mapping system: RIEDL insertion for epitope mapping (REMAP) method. We constructed 31 CD44 standard (CD44s) mutants where the RIEDL tag was inserted into the expected epitope region in CD44s. We observed that the C₄₄Mab-46 epitope constituted five amino acids: ₁₇₄-TDDDV-₁₇₈ of CD44s. Thus, the REMAP method could be used to determine mAb binding epitopes for membrane proteins.

Radiation doses of workers engaged in decontamination of the environment

After the accident at Fukushima Daiichi nuclear power plant on 11 March 2011, radioactive materials were released into the atmosphere resulting in environmental contamination. Following the implementation of environmental decontamination efforts, the Radiation Dose Registration Centre of the Radiation Effects Association established the radiation dose registration system for decontamination and related workers to consolidate and prevent the loss of radiation records. This article presents statistics on the radiation doses of decontamination and related workers using official records. Since approximately 10 years have passed since the accident in Fukushima, the types of work conducted in the affected restricted areas have changed over time. Therefore, changes in radiation dose for each type of work and comparisons with nuclear workers are presented.

Anti‑HER3 monoclonal antibody exerts antitumor activity in a mouse model of colorectal adenocarcinoma

HER3 belongs to the epidermal growth factor receptor (EGFR) family and is known to form an active heterodimer with other three family members EGFR, HER2, and HER4. HER3 is overexpressed in lung, breast, colon, prostate, and gastric cancers. In the present study, we developed and validated an anti-HER3 monoclonal antibody (mAb), H₃Mab-17 (IgG_2a, kappa), by immunizing mice with HER3-overexpressed CHO-K1 cells (CHO/HER3). H₃Mab-17 was found to react specifically with endogenous HER3 in colorectal carcinoma cell lines, using flow cytometry. The K_D for H₃Mab-17 in CHO/HER3 and Caco-2 (a colon cancer cell line) were determined to be 3.0×10⁻⁹ M and 1.5×10⁻⁹ M via flow cytometry, respectively, suggesting high binding affinity of H₃Mab-17 to HER3. Then, we assessed the H₃Mab-17 antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against Caco-2, and evaluated its antitumor capacity in a Caco-2 ×enograft model. In vitro experiments revealed H₃Mab-17 had strongly induced both ADCC and CDC against Caco-2 cells. In vivo experiments on Caco-2 ×enografts revealed that H₃Mab-17 treatment significantly reduced tumor growth compared with the control mouse IgG. These data indicated that H₃Mab-17 could be a promising treatment option for HER3-expressing colon cancers.

Ferret Podoplanin Is Detected by PMab-241 in Immunohistochemistry

Podoplanin (PDPN) plays an important role in the development of many normal tissues and is expressed in various cancers. We have previously developed multiple monoclonal antibodies (mAbs) against PDPNs from a variety of animal species and characterized each of these PDPNs using the anti-PDPN mAbs. In this study, we evaluated whether these anti-PDPN mAbs possess cross-reactivity with ferret PDPN (ferPDPN) using flow cytometry. Comprehensive analysis using 17 differing anti-PDPN mAbs available for immunohistochemistry use, demonstrated that the anti-bear PDPN mAb (clone PMab-241) strongly cross-reacts with ferPDPN-overexpressed Chinese hamster ovary-K1 (CHO/ferPDPN) cells. Immunohistochemistry analysis demonstrated intense PMab-241 staining within Bowman's capsules and glomeruli of the ferret kidney, and lymphatic endothelial cells of the ferret lung. These results demonstrate that PMab-241 is suitable for the detection of PDPN in ferret tissues.

Development of Anti-Human CC Chemokine Receptor 9 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 9 (CCR9) belongs to the beta chemokine receptor family and is mainly distributed on the surface of immature T lymphocytes and enterocytes. This receptor is highly expressed in rheumatoid arthritis, colitis, type 2 diabetes, and various tumors. Therefore, more sensitive monoclonal antibodies (mAbs) need to be developed to predict the prognosis of many high CCR9 expression diseases. Because CCR9 is a structurally unstable G protein-coupled receptor, it has been difficult to develop anti-CCR9 mAbs using the traditional method. This study developed anti-human CCR9 (hCCR9) mAbs for flow cytometry using a Cell-Based Immunization and Screening (CBIS) method. Two mice were immunized with hCCR9-overexpressed Chinese hamster ovary (CHO)-K1 cells (CHO/hCCR9), and hybridomas showing strong signals from CHO/hCCR9 and no signals from CHO-K1 cells were selected by flow cytometry. We established an anti-hCCR9 mAb, C₉Mab-1 (IgG₁, kappa), which detected hCCR9 in MOLT-4 leukemia T lymphoblast cells and CHO/hCCR9 cells by flow cytometry. Our study showed that an anti-hCCR9 mAb was developed more rapidly by the CBIS method than the previous method.

Development of an Anti-Elephant Podoplanin Monoclonal Antibody PMab-265 for Flow Cytometry

The development of specific antibodies is essential to understand a wide variety of biological phenomena and pathophysiological analyses. Podoplanin (PDPN), a type I transmembrane glycoprotein, is known as a diagnostic marker. Anti-PDPN monoclonal antibodies (mAbs) against many species, such as human, mouse, rat, rabbit, dog, bovine, cat, tiger, horse, pig, goat, alpaca, Tasmanian devil, bear, whale, and sheep, have been established in recent studies. However, sensitive and specific mAbs against elephant PDPN (elePDPN) have not been established. Thus, this study established a novel mAb against African savanna elephant (Loxodonta africana) PDPN using the Cell-Based Immunization and Screening method. elePDPN-overexpressed Chinese hamster ovary-K1 (CHO/elePDPN) cells were immunized, and mAbs were screened against elePDPN using flow cytometry. One of the mAbs, PMab-265 (IgM, κ), specifically detected CHO/elePDPN cells by flow cytometry. These findings suggested the potential usefulness of PMab-265 for the functional analyses of elePDPN.

Development of Monoclonal Antibody PMab-269 Against California Sea Lion Podoplanin

The development of protein-specific antibodies is essential for understanding a wide variety of biological phenomena. Parasitic and viral infections and cancers are known to occur within California sea lion (Zalophus californianus) populations. However, sensitive and specific monoclonal antibodies (mAbs) for the pathophysiological analysis of California sea lion tissues have not yet been developed. A type I transmembrane glycoprotein, podoplanin (PDPN), is a known diagnostic marker of lymphatic endothelial cells. We have previously developed several anti-PDPN mAbs in various mammalian species, with applications in flow cytometry, Western blotting, and immunohistochemistry. In this study, we established a novel mAb against California sea lion PDPN (seaPDPN), clone PMab-269 (mouse IgG₁, kappa), using a Cell-Based Immunization and Screening method. PMab-269 is specifically detected in seaPDPN-overexpressed Chinese hamster ovary (CHO)-K1 cells using flow cytometry and Western blotting. Moreover, PMab-269 clearly identified pulmonary type I alveolar cells, renal podocytes, and colon lymphatic endothelial cells in California sea lion tissues using immunohistochemistry. These findings demonstrate the usefulness of PMab-269 for the pathophysiological analysis of lung, kidney, and lymphatic tissues of the California sea lion.

An anti‑TROP2 monoclonal antibody TrMab‑6 exerts antitumor activity in breast cancer mouse xenograft models

Trophoblast cell surface antigen 2 (TROP2), reported to be overexpressed in several types of cancer, is involved in cell proliferation, invasion, metastasis, and poor prognosis of many types of cancer. Previously, a highly sensitive anti-TROP2 monoclonal antibody (clone TrMab-6; mouse IgG_2b, κ) was developed using a Cell-Based Immunization and Screening (CBIS) method. TrMab-6 was useful for investigations using flow cytometry, western blot, and immunohistochemistry. The aim of the present study was to investigate whether TrMab-6 possesses in vitro antibody-dependent cellular cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC) activities or in vivo antitumor activities using mouse xenograft models of TROP2-overexpressed CHO-K1 (CHO/TROP2) and breast cancer cell lines, including MCF7, MDA-MB-231, and MDA-MB-468. In vitro experiments revealed that TrMab-6 strongly induced ADCC and CDC activities against CHO/TROP2 and the three breast cancer cell lines, whereas it did not show those activities against parental CHO-K1 and MCF7/TROP2-knockout cells. Furthermore, in vivo experiments on CHO/TROP2 and MCF7 ×enografts revealed that TrMab-6 significantly reduced tumor growth, whereas it did not show antitumor activities against parental CHO-K1 and MCF7/TROP2-knockout xenografts. The findings suggest that TrMab-6 is a promising treatment option for TROP2-expressing breast cancers.

Development of Anti-Mouse CC Chemokine Receptor 3 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 3 (CCR3), also known as CD193, belongs to class A of G protein-coupled receptors and is present in high levels in eosinophils, basophils, and airway epithelial cells. CCR3 is considered the therapeutic target for human immunodeficiency virus (HIV) infections and allergic diseases; therefore, the development of sensitive monoclonal antibodies (mAbs) for CCR3 has been desired. This study aimed to establish a specific and sensitive mAb against mouse CCR3 (mCCR3) useful for flow cytometry analysis by employing the Cell-Based Immunization and Screening (CBIS) method. The generated anti-mCCR3 mAb, C₃Mab-2 (rat IgG_2b, kappa), was found to react with mCCR3-overexpressed Chinese hamster ovary-K1 (CHO/mCCR3) cells, according to flow cytometric analysis. Also, it reacted with P388 (mouse lymphoid neoplasm) or J774-1 (mouse macrophage-like) cells, which express endogenous mCCR3. Taken together, C₃Mab-2, generated by the CBIS method, can be a valuable tool for detecting mCCR3 on the surface of mouse cells.

Development of Antihuman Killer Cell Lectin-Like Receptor Subfamily G Member 1 Monoclonal Antibodies for Flow Cytometry

Killer cell lectin-like receptor subfamily G member 1 (KLRG1), a type II transmembrane protein, was identified as an inhibitory receptor expressed on natural killer (NK) cells and certain T cells. The protein regulates effector functions and developmental processes in these cells. In this study, we established a specific and sensitive monoclonal antibody (mAb) for human KLRG1 (hKLRG1), which is useful for flow cytometry, using a Cell-Based Immunization and Screening (CBIS) method. The established anti-hKLRG1 mAb, KLMab-1 (mouse IgG₁, kappa), reacted with overexpressed hKLRG1 in Chinese hamster ovary-K1 (CHO/hKLRG1) and human NK cells, which also expressed endogenous hKLRG1 as confirmed by flow cytometry. KLMab-1, which was established by the CBIS method, could be useful for elucidating the hKLRG1-related biological response by flow cytometry.

Development of Anti-human T Cell Immunoreceptor with Ig and ITIM Domains (TIGIT) Monoclonal Antibodies for Flow Cytometry

Immune checkpoint inhibitors targeting programmed cell death-ligand 1 (PD-L1), programmed cell death-1 (PD-1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) recently made a significant survival rate improvement in cancer treatment. T cell immunoreceptor with Ig and ITIM domains (TIGIT) is expressed in T and NK cells related to their activities. It has a single extracellular immunoglobulin domain, a type 1 transmembrane domain, and a single intracellular ITIM. TIGIT binds with poliovirus receptor (PVR) or PVR2, resulting in suppressing T and NK cell activities. Some studies showed that the combined use of a TIGIT inhibitor with another immune checkpoint inhibitor enhanced antitumor activities more strongly than their single use. Therefore, TIGIT should be a new target for immunotherapy. In this study, we developed new anti-human TIGIT (hTIGIT) monoclonal antibodies (mAbs) using the Cell-Based Immunization and Screening (CBIS) method. Mice were immunized with hTIGIT-overexpressed Chinese hamster ovary (CHO)-K1 cells (CHO/hTIGIT), and hybridomas were screened by flow cytometry. One of the mAbs, TgMab-2 (IgG₁, kappa), specifically and sensitively detects hTIGIT in CHO/hTIGIT and NK cells. The dissociation constants (K_D) of TgMab-2 for CHO/hTIGIT cells were determined to be 3.5 × 10^-9 M. These results suggest that TgMab-2, which was developed by CBIS method, is useful for analyzing the function of hTIGIT by flow cytometry.

Development of Anti-Mouse CC Chemokine Receptor 8 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 8 (CCR8) belongs to the class A of G protein-coupled receptor. It is highly expressed on Treg and T helper 2 (T_H2) cells recruited to the inflammation site and is implicated in allergy and asthma. Recently, CCR8+Treg cells have been suggested to be a master regulator in the immunosuppressive tumor microenvironment; therefore, developing sensitive monoclonal antibodies (mAbs) for CCR8 has been desired. This study established a specific and sensitive mAb for mouse CCR8 (mCCR8), which is useful for flow cytometry by using the Cell-Based Immunization and Screening (CBIS) method. The established anti-mCCR8 mAb, C₈Mab-2 (rat IgG_2b, kappa), reacted with mCCR8-overexpressed Chinese hamster ovary-K1 (CHO/mCCR8) cells and P388 (mouse lymphoid neoplasma) or J774-1 (mouse macrophage-like) cells, which express endogenous mCCR8 by flow cytometry. C₈Mab-2, which was established by the CBIS method, could be useful for elucidating the mCCR8-related biological response by flow cytometry.

Development of Novel Mouse Monoclonal Antibodies Against Human CD19

CD19 is a type I transmembrane glycoprotein belonging to the immunoglobulin superfamily. It is expressed in normal and neoplastic B cells, and it modulates the threshold of B cell activation for amplifying B cell receptor signaling. Blinatumomab (a CD3-CD19-bispecific T cell-engaging antibody) and tisagenlecleucel (genetically modified T cells that express a CD19 chimeric antigen receptor [CART-19]) provide significant benefits for patients with CD19-positive relapsed or refractory B cell malignancies. In this study, we first employed the Cell-Based Immunization and Screening (CBIS) method to produce anti-CD19 monoclonal antibodies using CD19-overexpressing cells for both immunization and screening. One established clone-C₁₉Mab-1-proved to be useful in flow cytometry assays against lymphoma cell lines, such as BALL-1, P30/OHK, and Raji. Second, the extracellular domain of CD19 was immunized into mice, and enzyme-linked immunosorbent assays were performed for the first screening. One established clone-C₁₉Mab-3-was determined to be useful for Western blotting and immunohistochemical analysis. Due to their complementary utility, a combination of C₁₉Mab-1 (established using CBIS) and C₁₉Mab-3 (established using conventional method) could be useful for the pathological analysis of CD19.

Epitope mapping of an anti-diacylglycerol kinase delta monoclonal antibody DdMab-1

Diacylglycerol kinase δ (DGKδ) is a type II DGK, which catalyzes diacylglycerol phosphorylation to produce phosphatidic acid. DGKδ is expressed in several types of tissues and organs including the stomach, testis, bone marrow, and lymph node. Here, we established an anti-human DGKδ (hDGKδ) mAb, DdMab-1 (mouse IgG_2a, kappa), which is useful for Western blot analysis. We also introduced deletion or point mutations to hDGKδ, and performed western blotting to determine the binding epitope of DdMab-1. DdMab-1 reacted with the dN670 mutant, but not with the dN680 mutant, indicating that the N-terminus of the DdMab-1 epitope is mainly located between amino acids 670 and 680 of the protein. Further analysis using point mutants demonstrated that R675A, R678A, K679A, and K682A mutants were not detected, and V680A was only weakly detected by DdMab-1, indicating that Arg675, Arg678, Lys679, Val680 and Lys682 are important for binding of DdMab-1 to hDGKδ.

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DGKδ catalyzes diacylglycerol phosphorylation to produce phosphatidic acid.

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We established a novel anti-hDGKδ mAb, DdMab-1.

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DdMab-1 is useful for Western blot analysis.

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R675, R678, K679, V680, and K682 are important for binding of DdMab-1 to hDGKδ.

Clinical risk predictors for bradycardia, supraventricular tachycardia and epilepsy necessitating therapy in patients with unexplained syncope monitored by insertable cardiac monitor

Background

Insertable cardiac monitors (ICMs) allow for lengthy monitoring of cardiac rhythm and improve diagnostic yield in patients with unexplained syncope. In most cardiac syncope cases, sick sinus syndrome, atrioventricular block, and paroxysmal supraventricular tachycardia (SVT) are detected using ICMs. On the other hand, epileptic seizures are sometimes diagnosed as unexplained syncope because in these situations, the loss of consciousness is a similar manifestation. Thus, the population of patients with unexplained syncope monitored by ICMs includes epileptic patients. Clinical risk factors for bradycardia, SVT and epilepsy that necessitate therapy in patients with unexplained syncope are not well known. If these risks can be clarified, clinicians could provide more specific targeted monitoring.

Purpose

We aimed to identify these predictors.

Methods

We retrospectively reviewed medical records of consecutive patients who received ICMs to monitor unexplained syncope in three medical facilities. We performed Cox's stepwise logistic regression analysis to identify significant independent risk factors for bradycardia, SVT, and epilepsy.

Results

One hundred thirty-two patients received ICMs to monitor unexplained syncope. During the 17-month follow-up period, 19 patients (10 patients had sick sinus syndrome and 9 had atrioventricular block) needed pacemaker for bradycardia; 8 patients (3 had atrial flutter, 4 had atrial tachycardia, and 1 had paroxysmal atrial fibrillation) needed catheter ablation for SVT; and 9 patients needed antiepileptic agents from the neurologist.Stepwise logistic regression analysis indicated that syncope during effort (odds ratio [OR] = 3.41; 95% confidence interval [CI], 1.21 to 9.6; p=0.02) was an independent risk factor for bradycardia. Palpitation before syncope (OR = 9.46; 95% CI, 1.78 to 50.10; p=0.008) and history of atrial fibrillation (OR = 10.1; 95% CI, 1.96 to 52.45; p=0.006) were identified as significant independent prognostic factors for SVT. Syncope while supine (OR = 11.7; 95% CI, 1.72 to 79.7; p=0.01) or driving (OR = 15.6; 95% CI, 2.10 to 115.3; p=0.007) was an independent factor for epileptic seizure.

Conclusions

ICMs are useful devices for diagnosing unexplained syncope. Palpitation, atrial fibrillation and syncope during effort were independent risk factors for bradycardia and for SVT. Syncope while supine or driving was an independent risk factor for epilepsy. We should carefully follow up of patients with these risk factors.

Funding Acknowledgement

Type of funding source: None

Relationship between age and the impact of revascularization on mortality in patients with non-ST-elevation myocardial infarction

Background

It is known that the early coronary revascularization in patients with non-ST-elevation myocardial infarction (NSTEMI) was associated with favorable clinical outcomes. However, it is still unclear whether this efficacy is equivalent over all the ages of the patients.

Methods

Patients with NSTEMI were screened from the database of the Tokyo CCU network registry. Of those, the patients treated without revascularization (medical treatment) were matched with the patients receiving revascularization by propensity score matching. The probabilities of in-hospital death were calculated in the logistic regression model. In two subgroups stratified according to median of the age (elderly and non-elderly subgroups), the odds ratios of revascularization for in-hospital death were calculated.

Results

In the patients registered between 2013 and 2017, 4,851 patients with NSTEMI were identified. After the screening, 370 patients with medical treatment were matched with 370 patients treated with revascularization. The incidence of in-hospital death was significantly higher in the patients with medical treatment (20.3% vs 13.0%, P=0.01). The two probability curves of in-hospital death in patients with and without revascularization converged as age increased. In the elderly subgroup, the revascularization was not significantly associated with favorable outcome of mortality, whereas it had a significant impact on mortality in the non-elderly subgroup (odds ratio: 0.47 [95% CI 0.23–0.95]).

Conclusion

The impact of revascularization on short-term mortality in patients with NSTEMI tended to be reduced as age increased.

Funding Acknowledgement

Type of funding source: None

The impact of low diastolic blood pressure on 30-day mortality of patients with acute myocardial infarction

Background

It is known that low diastolic blood pressure (DBP) is associated with long-term cardiovascular events after acute myocardial infarction (AMI). However, the impact of low diastolic blood pressure on short-term outcome has not yet been well investigated.

Methods and results

We included 15,208 patients who were hospitalized for AMI and registered in the Tokyo CCU network registry between 2013 and 2016. Thirty-day in-hospital mortality rate was 4.8% (728/15,208). To assess the relationship between DBP at the time of admission and 30-day mortality non-linearly, spline regression model was applied with the stratification of the cohort according to tercile of systolic blood pressure (SBP, low:≤122 mmHg, intermediate:123–148 mmHg, high:≥149 mmHg) and J-curve phenomenon was observed in the low and high SBP groups. In multivariate logistic regression analysis, adjusted odds ratio of the lowest quintile of DBP (≤64 mmHg) was 1.65 (95% CI:1.02–2.66) in low SBP group and 4.55 (95% CI:1.72–12.00) in high SBP group.

Conclusion

Low DBP was associated with increased 30-day in-hospital mortality rate after AMI even in patients with high SBP.

Funding Acknowledgement

Type of funding source: None

Twenty-year trends in clinical outcome of randomized controlled trial for coronary intervention: systematic review and meta-regression analysis of 46 randomized controlled trials

Aim

The technology of percutaneous coronary intervention (PCI) has been developed after the advent of coronary stent. However, the impact of the technological development on clinical outcomes is still unclear, whereas a remarkable improvement of clinical outcomes after PCI has not been observed in the trials comparing to medical therapy or coronary bypass graft. The current analysis aims to investigate trends in clinical outcomes after PCI after the emargence of coronary stent, using the randomized controlled trials (RCTs) comparing coronary stents.

Methods and results

We performed a systematic review of RCTs investigating coronary stents in non-specific population (excluding the trials particularly enrolling diabetic or myocardial infarction etc.) conducted between 1996 and 2015 (publication between 1997 and 2019) with independent clinical event adjudication. The random-effect meta-regression analysis including 90 arms with 94,831 patients in 46 RCTs was performed investigating the 20-year trends in clinical outcomes such as death, cardiac death, myocardial infarction, target lesion revascularization (TLR) and stent thrombosis at one and five years after the index procedure. The sensitivity analysis was performed by limiting to 20 all comer trials. In the meta-regression analysis, we did not observe significant change in the incidences of cardiac death and myocardial infarction after PCI over 20 years (P values for cardiac death: 0.666 at one year, 0.256 at five years and P values for myocardial infarction: 0.121 at one year, 0.376 at five years; R2 for cardiac death: <0.01 at one year and five years and R2 for myocardial infarction: <0.01 at one year and five years), whereas the incidences of clinically indicated TLR (P value <0.001, R2 = 0.40 at one year, P value = 0.002, R2 = 0.22 at five years) and stent thrombosis were decreased steeply in the first decade and slightly in the second decade (P value = 0.040, R2 = 0.09 at one year; P value = 0.017, R2 = 0.17 at five year). The sencitivity analysis limiting all-comer population revealed the consistent results.

Conclusion

The development of PCI had an impact on the 20-year trends in TLR and ST, despite there were no trends in the cardiac death and myocardial infarction.

Trends in the incidence of the outcomes

Funding Acknowledgement

Type of funding source: None

The anti-epithelial cell adhesion molecule (EpCAM) monoclonal antibody EpMab-16 exerts antitumor activity in a mouse model of colorectal adenocarcinoma

The epithelial cell adhesion molecule (EpCAM), which is a calcium-independent homophilic intercellular adhesion factor, contributes to cell signaling, differentiation, proliferation and migration. EpCAM is essential for carcinogenesis in numerous types of human cancer. The purpose of the present study was to establish an anti-EpCAM monoclonal antibody (mAb) for targeting colorectal adenocarcinomas. Thus, an anti-EpCAM mAb, EpMab-16 (IgG_2a, κ), was established by immunizing mice with EpCAM-overexpressing CHO-K1 cells, and validated using flow cytometry, western blot, and immunohistochemical analyses. EpMab-16 reacted with endogenous EpCAM specifically in a colorectal adenocarcinoma cell line as determined by flow cytometry and western blot analyses. Immunohistochemical analysis demonstrated that EpMab-16 stained a plasma membrane-like pattern in clinical colorectal adenocarcinoma tissues. The dissociation constant (K _D) for EpMab-16 in a Caco-2 colorectal adenocarcinoma cell line determined by flow cytometry was 1.8×10^-8 M, suggesting moderate binding affinity of EpMab-16 for EpCAM. Whether the EpMab-16 induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against Caco-2 or antitumor activity was then assessed in a murine xenograft model. In vitro experiments revealed strong ADCC and CDC induction in Caco-2 cells by EpMab-16 treatment. In vivo experiments in a Caco-2 ×enograft model demonstrated that EpMab-16 treatment significantly reduced tumor growth compared with that in mice treated with the control mouse IgG. These results suggested that EpMab-16 may be a promising treatment option for EpCAM-expressing colorectal adenocarcinomas.

Anti‑EpCAM monoclonal antibody exerts antitumor activity against oral squamous cell carcinomas

The epithelial cell adhesion molecule (EpCAM) is a calcium-independent, homophilic, intercellular adhesion factor classified as a transmembrane glycoprotein. In addition to cell adhesion, EpCAM also contributes to cell signaling, differentiation, proliferation, and migration. EpCAM is an essential factor in the carcinogenesis of numerous human cancers. In the present study, we developed and validated an anti-EpCAM monoclonal antibody (mAb), EpMab-16 (IgG_2a, kappa), by immunizing mice with EpCAM-overexpressing CHO-K1 cells. EpMab-16 specifically reacted with endogenous EpCAM in oral squamous cell carcinoma (OSCC) cell lines in flow cytometry and Western blot analyses. It exhibited a plasma membrane-like stain pattern in OSCC tissues upon immunohistochemical analysis. The K_D for EpMab-16 in SAS and HSC-2 OSCC cells were assessed via flow cytometry at 1.1×10⁻⁸ and 1.9×10⁻⁸ M, respectively, suggesting moderate binding affinity of EpMab-16 for EpCAM. We then assessed whether the EpMab-16 induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against OSCC cell lines, and antitumor capacity in a murine xenograft model. In vitro experiments revealed strong ADCC and CDC inducement against OSCC cells treated with EpMab-16. In vivo experiments on OSCC xenografts revealed that EpMab-16 treatment significantly reduced tumor growth compared with the control mouse IgG. These data indicated that EpMab-16 could be a promising treatment option for EpCAM-expressing OSCCs.

Anti‑EGFR monoclonal antibody 134‑mG2a exerts antitumor effects in mouse xenograft models of oral squamous cell carcinoma

The epidermal growth factor receptor (EGFR), a transmembrane receptor and member of the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases, is a critical mediator of cell growth and differentiation. EGFR forms homo- or heterodimers with other HER family members to activate downstream signaling cascades in a number of cancer cells. In a previous study, the authors established an anti-EGFR monoclonal antibody (mAb), EMab-134, by immunizing mice with the ectodomain of human EGFR. EMab-134 binds specifically to endogenous EGFR and can be used to detect receptor on oral cancer cell lines by flow cytometry and western blot analysis; this antibody is also effective for the immunohistochemical evaluation of oral cancer tissues. In the present study, the subclass of EMab-134 was converted from IgG₁ to IgG_2a (134-mG_2a) to facilitate antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). The dissociation constants (K_Ds) of EMab-134 and 134-mG_2a against EGFR-expressing CHO-K1 (CHO/EGFR) cells were deter-mined by flow cytometry to be 3.2×10⁻⁹ M and 2.1×10⁻⁹ M, respectively; these results indicate that 134-mG_2a has a higher binding affinity than EMab-134. The 134-mG_2a antibody was more sensitive than EMab-134 with respect to antigen detection in oral cancer cells in both western blot analysis and immunohistochemistry applications. Analysis in vitro revealed that 134-mG_2a contributed to high levels of ADCC and CDC in experiments targeting CHO/EGFR, HSC-2, and SAS cells. Moreover, the in vivo administration of 134-mG_2a significantly inhibited the development of CHO/EGFR, HSC-2, and SAS mouse xenografts in comparison to the results observed in response to EMab-134. Taken together, the findings of the present study demonstrate that the newly-formulated 134-mG_2a is useful for detecting EGFR by flow cytometry, western blot analysis and immunohistochemistry. Furthermore, the in vivo results suggested that it may also be useful as part of a therapeutic regimen for patients with EGFR-expressing oral cancer.

A defucosylated anti‑CD44 monoclonal antibody 5‑mG2a‑f exerts antitumor effects in mouse xenograft models of oral squamous cell carcinoma

CD44 is widely expressed on the surface of most tissues and all hematopoietic cells, and regulates many genes associated with cell adhesion, migration, proliferation, differentiation, and survival. CD44 has also been studied as a therapeutic target in several cancers. Previously, an anti-CD44 monoclonal antibody (mAb), C₄₄Mab-5 (IgG₁, kappa) was established by immunizing mice with CD44-overexpressing Chinese hamster ovary (CHO)-K1 cells. C₄₄Mab-5 recognized all CD44 isoforms, and showed high sensitivity for flow cytometry and immunohistochemical analysis in oral cancers. However, as the IgG₁ subclass of C₄₄Mab-5 lacks antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), the antitumor activity of C₄₄Mab-5 could not be determined. In the present study, we converted the mouse IgG₁ subclass antibody C₄₄Mab-5 into an IgG_2a subclass antibody, 5-mG_2a, and further produced a defucosylated version, 5-mG_2a-f, using FUT8-deficient ExpiCHO-S (BINDS-09) cells. Defucosylation of 5-mG_2a-f was confirmed using fucose-binding lectins, such as AAL and PhoSL. The dissociation constants (K_D) for 5-mG_2a-f against SAS and HSC-2 oral cancer cells were determined through flow cytometry to be 2.8×10⁻¹⁰ M and 2.6×10⁻⁹ M, respectively, indicating that 5-mG_2a-f possesses extremely high binding affinity. Furthermore, immunohistochemical staining using 5-mG_2a-f specifically stained the membranes of oral cancer cells. In vitro analysis demonstrated that 5-mG_2a-f showed moderate ADCC and CDC activities against SAS and HSC-2 oral cancer cells. In vivo analysis revealed that 5-mG_2a-f significantly reduced tumor development in SAS and HSC-2 ×enografts in comparison to control mouse IgG, even after injection seven days post-tumor inoculation. Collectively, these results suggest that treatment with 5-mG_2a-f may represent a useful therapy for patients with CD44-expressing oral cancers.

RIEDL tag: A novel pentapeptide tagging system for transmembrane protein purification

Affinity tag systems are an essential tool in biochemistry, biophysics, and molecular biology. Although several different tag systems have been developed, the epitope tag system, composed of a polypeptide “tag” and an anti-tag antibody, is especially useful for protein purification. However, almost all tag sequences, such as the FLAG tag, are added to the N- or C-termini of target proteins, as tags inserted in loops tend to disrupt the functional structure of multi-pass transmembrane proteins. In this study, we developed a novel “RIEDL tag system,” which is composed of a peptide with only five amino acids (RIEDL) and an anti-RIEDL monoclonal antibody (mAb), LpMab-7. To investigate whether the RIEDL tag system is applicable for protein purification, we conducted the purification of two kinds of RIEDL-tagged proteins using affinity column chromatography: whale podoplanin (wPDPN) with an N-terminal RIEDL tag (RIEDL-wPDPN) and human CD20 with an internal RIEDL tag insertion (CD20-₁₆₉RIEDL₁₇₀). Using an LpMab-7-Sepharose column, RIEDL-wPDPN and CD20-₁₆₉RIEDL₁₇₀ were efficiently purified in one-step purification procedures, and were strongly detected by LpMab-7 using Western blot and flow cytometry. These results show that the RIEDL tag system can be useful for the detection and one-step purification of membrane proteins when inserted at either the N-terminus or inserted in an internal loop structure of multi-pass transmembrane proteins.

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We established a novel RIEDL tag system, composed of RIEDL peptide and LpMab-7 mAb.

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The RIEDL tag system is applicable for protein purification, as well as FCM and WB.

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The RIEDL tag, inserted into a loop structure of CD20, was detected by LpMab-7.

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RIEDL-tagged proteins were efficiently purified using 2 × RIEDL peptide.

Development and Characterization of Anti-Sheep Podoplanin Monoclonal Antibodies PMab-253 and PMab-260

Anti-podoplanin (PDPN) monoclonal antibodies (mAbs) are needed as markers for lymphatic endothelial cells or type I alveolar cells in immunohistochemical analyses. We have developed anti-PDPN mAbs for many species, including humans, mice, rats, rabbits, dogs, cats, bovines, pigs, Tasmanian devils, alpacas, tigers, whales, goats, horses, and bears. This study develops and characterizes anti-sheep PDPN (sPDPN) mAbs using Cell-Based Immunization and Screening (CBIS) method. A RAP14 tag was added to the N-terminus of sPDPN, and an anti-RAP14 tag mAb (PMab-2) was used to measure the expression level of sPDPN in flow cytometry and Western blots. We immunized mice with sPDPN-overexpressing Chinese hamster ovary (CHO)-K1 (CHO/sPDPN) cells and screened mAbs against sPDPN using flow cytometry. Two of the mAbs, PMab-253 (immunoglobulin M [IgM], kappa) and PMab-260 (IgM, kappa), detected CHO/sPDPN cells specifically using flow cytometry and Western blots. Both PMab-253 and PMab-260 stained the renal glomerulus and Bowman's capsule, lymphatic endothelial cells of the lung and colon, and type I alveolar cells of the lung, suggesting PMab-253 and PMab-260, which were developed by CBIS method, can be applied to functional analyses of sPDPN. We also determined the binding epitope of PMab-253 and PMab-260 using flow cytometry. Analysis of sPDPN deletion mutants revealed that the N-terminus of the PMab-253 and PMab-260 epitope exists between amino acids 110 and 115 of sPDPN. Analysis of sPDPN point mutations revealed that the critical epitope of PMab-253 and PMab-260 includes Thr112 and Ser113 of sPDPN, indicating that the PMab-253 and PMab-260 epitope are independent of the platelet aggregation-stimulating (PLAG) domain or the PLAG-like domain of sPDPN.

An Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody H2Mab-19 Exerts Antitumor Activity in Mouse Colon Cancer Xenografts

Trastuzumab is a humanized antibody against human epidermal growth factor receptor 2 (HER2) that offers significant survival benefits to patients with HER2-overexpressing breast or gastric cancer. HER2 is also known to be overexpressed in colon cancers. In this study, a novel anti-HER2 monoclonal antibody (mAb), H₂Mab-19 (IgG_2b, κ) was characterized for its anticancer activity in colon cancers. H₂Mab-19 showed both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activities against Caco-2, a colon cancer cell line. Furthermore, H₂Mab-19 significantly reduced tumor development in a Caco-2 xenograft model. These results suggest that treatment with H₂Mab-19 may be a useful therapy for patients with HER2-expressing colon cancers.

Epitope Mapping of the Anti-Diacylglycerol Kinase Monoclonal Antibody DhMab-4 for Immunohistochemical Analysis

Diacylglycerol kinase (DGK) plays a pivotal role in intracellular signaling pathways in mammals. Activated G protein-coupled receptor activates phospholipase C (PLC) through heterotrimeric G protein, following which PLC hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP₂) into diacylglycerol (DG) and inositol 1,4,5-trisphosphate (IP₃). DGK catalyzes DG phosphorylation to produce phosphatidic acid. DG and phosphatidic acid function as second messengers and their intracellular concentrations are regulated by DGK; therefore, DGK plays an important role in regulating many biological processes. There are ten DGK isozymes, of which DGKη is classified as a type II DGK. Reports have shown that DGKη is associated with several diseases; for example, it is highly expressed in the hippocampus and cerebellum and is a key element in bipolar disorder. Although a DGKη-specific monoclonal antibody (mAb) is necessary to reveal the association between the expression of DGKη and diseases, an anti-DGKη mAb for immunohistochemistry has not yet been established. In this study, we established a specific anti-human DGKη (hDGKη) mAb, DhMab-4 (mouse IgG_2b, kappa). DhMab-4 strongly stained Purkinje cells of human cerebellum in immunohistochemistry analysis. For epitope mapping of DhMab-4, we produced deletion or point mutants of hDGKη and performed western blotting to determine the binding epitope of DhMab-4. DhMab-4 reacted with dN745 mutant but not with dN750 mutant, indicating that the N-terminus of the DhMab-4 epitope is located between amino acids 745 and 750. More detailed analysis using point mutants demonstrated that five mutants, that is, D747A, P748A, F749A, G750A, and T752A, were not detected by DhMab-4. These results indicate that Asp747, Pro748, Phe749, Gly750, and Thr752 are important for DhMab-4 binding to hDGKη.

Thr80 of Sheep Podoplanin Is a Critical Epitope of the Antisheep Podoplanin Monoclonal Antibody: PMab-256

An antisheep podoplanin (sPDPN) monoclonal antibody (mAb), PMab-256, has recently been established. PMab-256 shows positive immunostaining for lymphatic endothelial cells, lung type I alveolar cells, and kidney podocytes. PDPN possesses three platelet-aggregation-stimulating (PLAG) domains, PLAG1, PLAG2, and PLAG3, and a PLAG-like domain (PLD). The binding epitope of many anti-PDPN mAbs is located in PLAG domains or PLD. The purpose of this study is to determine the binding epitope of PMab-256. Analysis of sPDPN deletion mutants revealed that the N-terminus of the PMab-256 epitope exists between amino acids 75 and 80 of sPDPN. Furthermore, analysis of sPDPN point mutations demonstrated that the critical epitope includes Thr80 of sPDPN, indicating that the PMab-256 epitope is in the PLD of sPDPN.

H2Mab-19 Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody Therapy Exerts Antitumor Activity in Pancreatic Cancer Xenograft Models

Overexpression of human epidermal growth factor receptor 2 (HER2) has been reported in breast cancer, gastric, lung, colorectal, oral, and pancreatic cancers. HER2 expression is associated with poor clinical outcomes. An anti-HER2 humanized antibody, trastuzumab, has improved survival rates in patients with HER2-overexpressing breast and gastric cancers. Previously, we established a novel anti-HER2 monoclonal antibody (mAb), H₂Mab-19 (IgG_2b, kappa). It has also been characterized for breast, oral, and colon cancers. In this study, we investigated the antitumor activities of H₂Mab-19 in pancreatic cancer xenograft models. We selected MIA PaCa-2, a pancreatic cancer cell line which expresses HER2. H₂Mab-19 showed high binding affinity (K_D: 1.2 × 10^-8 M) against MIA PaCa-2 cells. Furthermore, H₂Mab-19 significantly reduced tumor development in a MIA PaCa-2 xenograft model. These results suggest that treatment with H₂Mab-19 may be a useful therapy for patients with HER2-expressing pancreatic cancers.

Detection of Lion Podoplanin Using the Antitiger Podoplanin Monoclonal Antibody PMab-231

Monoclonal antibodies (mAbs) that specifically target podoplanin (PDPN), a marker for type I alveolar cells, are needed for immunohistochemical analyses. Anti-PDPN mAbs are available for many species, including human, mouse, rat, rabbit, dog, cat, bovine, pig, Tasmanian devil, alpaca, tiger, whale, goat, horse, bear, and sheep PDPNs. However, no antilion PDPN (lioPDPN) antibody has been developed. In this study, possible cross-reaction between available anti-PDPN mAbs and lioPDPN was examined. Immunohistochemical analysis showed that antitiger PDPN mAb PMab-231 (IgG_2a, kappa) reacted with type I alveolar cells from lion lung, indicating that PMab-231 is useful for the detection of lioPDPN.

Epitope Mapping of PMab-241, a Lymphatic Endothelial Cell-Specific Anti-Bear Podoplanin Monoclonal Antibody

Anti-bear podoplanin (bPDPN) monoclonal antibodies (mAbs), including PMab-247 and PMab-241, have been previously established. Although PMab-247 has shown positive immunostaining for lymphatic endothelial cells (LECs), type I alveolar cells of the lung, and podocytes of the kidney, PMab-241 stains LECs but does not react with lung type I alveolar cells. PDPN possesses three platelet aggregation-stimulating (PLAG) domains (PLAG1, PLAG2, and PLAG3) and the PLAG-like domain (PLD). The binding epitope of PMab-247 was previously determined to include bPDPN residues Asp76, Arg78, Glu80, and Arg82. Among these, Glu80 and Arg82 are included in PLD of bPDPN. The purpose of this study is to determine the binding epitope of PMab-241 and to clarify the difference between these two anti-bPDPN mAbs. Analysis of bPDPN deletion mutants revealed that the N-terminus of the PMab-241 epitope exists between amino acids (aa) 75 and 80 of bPDPN. In addition, analysis of bPDPN point mutants demonstrated that the critical epitope of PMab-241 includes Thr75, Asp76, and Arg78 of bPDPN. The binding epitopes of PMab-241 and PMab-247 seem to overlap, but this slight difference may be sufficient to provide the specificity of PMab-241 to discriminate LECs from type I alveolar cells of the lung.

Antibody-Drug Conjugates Using Mouse-Canine Chimeric Anti-Dog Podoplanin Antibody Exerts Antitumor Activity in a Mouse Xenograft Model

Antibody-drug conjugates (ADCs), which consist of a monoclonal antibody (mAb), a linker, and a payload, can deliver a drug to cancer tissues. We previously produced an anti-dog podoplanin (dPDPN) mAb, PMab-38, which reacts with dPDPN-expressing canine melanomas and squamous cell carcinomas (SCCs), but not with dPDPN-expressing canine type I alveolar cells or lymphatic endothelial cells, indicating that PMab-38 possesses cancer specificity. In this study, we developed an ADC, P38B-DM1, using the mouse-canine chimeric anti-dPDPN antibody, P38B as the antibody, a peptide linker, and emtansine as the payload using the chemical conjugation by affinity peptide (CCAP) method. We investigated its cytotoxicity against dPDPN-overexpressed Chinese hamster ovary (CHO/dPDPN) cells in vitro and its antitumor activity using a mouse xenograft model of CHO/dPDPN cells. P38B-DM1 showed cytotoxicity to CHO/dPDPN cells in a dose-dependent manner in vitro. Furthermore, P38B-DM1 exhibited higher antitumor activity than P38B in the mouse xenograft model. These results suggest that P38B-DM1, developed using the CCAP method, is useful for antibody therapy against dPDPN-expressing canine SCCs and melanomas.

Validation of Real-Time PCR Analyses for Line-Specific Quantitation of Genetically Modified Maize and Soybean UsingNew Reference Molecules

Novel analytical methods based on real-time quantitative polymerase chain reactions by use of new reference molecules were validated in interlaboratory studies for the quantitation of genetically modified (GM) maize and soy. More than 13 laboratories from Japan, Korea, and the United States participated in the studies. The interlaboratory studies included 2 separate stages: (1) measurement tests of coefficient values, the ratio of recombinant DNA (r-DNA) sequence, and endogenous DNA sequence in the seeds of GM maize and GM soy; and (2) blind tests with 6 pairs of maize and soy samples, including different levels of GM maize or GM soy. Test results showed that the methods are applicable to the specific quantitation of the 5 lines of GM maize and one line of GM soy. After statistical treatment to remove outliers, the repeatability and reproducibility of these methods at a level of 5.0% were <13.7 and 15.9%, respectively. The quantitation limits of the methods were 0.50% for Bt11, T25, and MON810, and 0.10% for GA21, Event176, and Roundup Ready soy. The results of blind tests showed that the numerical information obtained from these methods will contribute to practical analyses for labeling systems of GM crops.

P1643An exploratory analysis for the optimal monitoring interval of N-terminal pro-B-type natriuretic peptide in patients with stable heart failure

Background

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a potential biomarker for monitoring the status of heart failure. However, the optimal monitoring interval is unknown. This study aims to investigate minimal informative monitoring interval of NT-proBNP in patients with stable chronic heart failure.

Methods

In this retrospective open cohort study, adult patients followed up at a tertiary hospital for chronic heart failure with NT-proBNP measurements were included if they had been previously admitted due to acute heart failure and were free from readmission over 6 months after discharge. We analyzed NT-proBNP measured between 6 months after discharge and the timepoint of an alteration of medication regimen or readmission due to worsening of heart failure. To distinguish actual progression of the disease from biological variability and measurement error, the signal-to-noise ratio method was applied with a random-effects model. Stratified analysis was performed according to underlying risks.

Results

In this analysis, 368 patients were included with NT-proBNP measured between July 2009 and December 2017. The patients had 6.0 times of NT-proBNP measurements in median (interquartile range [IQR] 4.0–10.0) during the follow-up period (median 12.0 months [IQR 6.0–27.0]). In the estimates of the random-effects model, signal (i.e. actual progression of the disease) exceeded noise (i.e. biological variability and measurement error) at 8.1 months (95% confidence interval [CI]: 5.7–10.1) after the index measurement. In a subgroup analysis according to the AHEAD risk score, the minimal informative monitoring interval was shortened as the risk score increased (0–1 point: 12.3 months [95% CI: 10.3–14.5]; 2–3 points: 8.0 months [95% CI: 6.8–9.7]; 4–5 points: 3.3 months [95% CI: 3.0–3.8]; Figure).

Informative intervals stratified by risk

Conclusion

In patients with stable chronic heart failure, the overall minimal informative monitoring interval of NT-proBNP measurement was 8.1 months, which varies by underlying risk. The optimal monitoring interval could be lengthened especially for patients at lower risk.

Cavity resonator for circularly polarized microwave irradiation mounted on a cryostat

We have constructed a cylindrical cavity resonator with a hybrid coupler where circularly polarized microwaves can be irradiated to a sample. The polarity of the microwave can be switched by changing the input ports of the hybrid coupler. The cavity resonator is small enough to be mounted on a cryostat which enables us to change the sample temperature in a wide range. To demonstrate the performance of the cavity resonator mounted on a cryostat, Yttrium Iron Garnet (YIG) was used as a test sample. We succeeded in selectively exciting left and right circularly polarized modes with high polarization (>80%). We also evaluated the susceptibility tensor of YIG in the cryostat. The technique presented here would offer a new direction in the fields of spintronics and quantum information.

Epicatechin downregulates adipose tissue CCL19 expression and thereby ameliorates diet-induced obesity and insulin resistance

BACKGROUND AND AIMS

Epicatechin (EC) intake has been suggested to be beneficial for the prevention of cardiovascular disorders, and it is well known that adipose tissue inflammation is one of the major risk factors for coronary heart diseases. The purpose of the present study was to determine the in vitro and in vivo effects of EC on adipose tissue inflammation and obesity.

METHODS AND RESULTS

DNA microarray analysis was performed to evaluate the effects of EC on gene expression in adipocytes co-cultured with bacterial endotoxin-stimulated macrophages. To determine the in vivo effects of the catechin, C57BL/6 mice were fed either a high-fat diet (HFD) or HFD combined with EC, and metabolic changes were observed EC suppressed the expression of many inflammatory genes in the adipocytes co-cultured with endotoxin-stimulated macrophages. Specifically, EC markedly suppressed chemokine (CC motif) ligand 19 (CCL19) expression. The target cell of EC appeared to macrophages. The in vivo study indicated that mice fed the EC-supplemented HFD were protected from diet-induced obesity and insulin resistance. Accordingly, the expression levels of genes associated with inflammation in adipose tissue and in the liver were downregulated in this group of mice.

CONCLUSIONS

EC exerts beneficial effects for the prevention of adipose tissue inflammation and insulin resistance. Since we previously reported that mice deficient in the CCL19 receptor were protected from diet-induced obesity and insulin resistance, it can be concluded that the beneficial effects of EC could be mediated, at least in part, by marked suppression of CCL19 expression.

Effect of oxygen vacancy segregation in Au or Pt/oxide hetero-interfaces on electronic structures

We investigated the effects of oxygen vacancy segregation on electronic structures in the vicinity of hetero-interfaces between noble metals (Au and Pt) and yttria stabilized zirconia by performing first-principles calculations and Bader analysis.