ACE values in the diagnosis of sarcoidosis

Background

In clinical practice, we often encounter the patients with sarcoidosis showing relatively high in the normal range of serum angiotensin-converting enzyme (ACE) value.

Purpose

We aimed to examine the serum ACE value of the patients with sarcoidosis and determine the new cut-off value for detecting the patients with sarcoidosis.

Methods and results

We retrospectively examined all 3781 subjects (51.1% men, 60.1±17.0 y.o.) in whom ACE was measured for any reasons including suspected sarcoidosis between 2009 and 2020 in our hospital. Of 293 patients with sarcoidosis, 101, 212, 84, and 88 were diagnosed as sarcoidosis in heart, lung, skin, and eyes, respectively. After excluding 477 patients taking ACE inhibitor and/or immunosuppression agent or those with any diseases affecting serum ACE levels, we analyzed 3304 subjects including 215 with sarcoidosis. Serum ACEs were 19.6 IU/L [IQR, 15.1–31.5] in the subjects with sarcoidosis and 10.7 [8.4–16.5] in those without (P<0.01). In ROC curve analysis of ACE for diagnosis of sarcoidosis, the cut-off point was 14.7 IU/L and the AUC was 0.865. When we used the current cut-off of 21.4 or new cut-off value of 14.7, sensitivity, specificity, PPV, NPV, and accuracy were shown in Table. Finally, they were divided into four groups based on the presence of cardiac and/or extra cardiac sarcoidosis, ACE values in Group A, B, C, and D were 17.9, 20.9, 18.6, and 10.7, respectively (Figure 1).

Conclusion(s)

In the current cut-off value of serum ACE, sensitivity for detecting sarcoidosis was comparatively low, though positive predictive value was low when the new-cut-off value was used in our study. Further examinations may be needed for the patients suspected sarcoidosis with relatively high ACE in the normal range.

Funding Acknowledgement

Type of funding sources: None.

Determinants of left atrioventricular coupling index: the multi-ethnic study of atherosclerosis (MESA)

Background

Recent studies have described a novel left atrioventricular coupling index (LACI), which had a better prognostic value than individual left atrial (LA) or left ventricular (LV) parameters measured separately to predict cardiovascular events.

Purpose

To identify the determinants of the LACI and its 10-year annual change (ΔLACI), measured by cardiovascular magnetic resonance (CMR), and to better understand the parameters governing this left atrioventricular coupling.

Methods

In the Multi-Ethnic Study of Atherosclerosis (MESA), 2,112 study participants, free of cardiovascular disease at baseline, had LACI assessed by CMR imaging at baseline (LACIBaseline, 2000–2002) and 10 years later (2010–2012). The LACI was defined as the ratio of LA to LV end-diastolic volumes. Linear regression analyses were performed to identify independent determinants of LACIBaseline or ΔLACI.

Results

In the 2,112 participants (58.8±9.1 years, 46.6% male), after adjustment for all covariates, age was independently associated with both LACIBaseline (R2=0.10, slope=0.16) and ΔLACI (R2=0.15, slope=0.008, both p<0.001). African Americans had the highest LACIBaseline value (18.0±7.7%). Although there was no difference in LACIBaseline between women and men (p=0.19), ΔLACI was higher in women than in men (1.0±1.1 vs. 0.8±1.0%/year, p<0.001). Diabetes and a higher BMI were independently associated with LACIBaseline (both p<0.001). LACIBaseline was independently associated with LV myocardial fibrosis markers (native T1: R2=0.11, slope = 0.09, p=0.038; and extra-cellular volume: R2=0.08, slope = 0.28, p=0.035) and NT-proBNP levels (R2=0.10, slope = −1.11, p<0.001) but was not associated with IL-6 or hsCRP.

Conclusions

Age, sex, ethnicity, diabetes, and BMI were independent determinants of LACI. LACI was independently associated with LV myocardial fibrosis markers and NT-proBNP levels.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of a left atrioventricular coupling index (LACI) in pre- and post-menopausal women. from the multi-ethnic study of atherosclerosis (MESA)

Background

Endogenous sex hormones associated with both the left atrial (LA) and left ventricular (LV) structures in peri-menopausal women, but the association of menopause status with left atrioventricular coupling is not well established.

Purpose

To assess the prognostic value of a left atrioventricular coupling index (LACI) in pre- and post-menopausal women without a history of cardiovascular disease (CVD) at baseline in the Multi-Ethnic Study of Atherosclerosis (MESA).

Methods

In women participating in the MESA study, the LACI was measured as the ratio of the left atrial (LA) end-diastolic volume to the left ventricular (LV) end-diastolic volume using cardiovascular magnetic resonance (CMR). Cox proportional hazard models were used to assess the association between the LACI and the outcomes of atrial fibrillation (AF), heart failure (HF), and hard CVD defined by myocardial infarction, resuscitated cardiac arrest, stroke, or coronary heart disease death.

Results

Among the 2,087 women participants (61±10 years), 485 cardiovascular events were observed during the mean follow-up period of 13.2±3.3 years. A higher LACI was independently associated with AF (HR 1.70; 95% CI [1.51–1.90]), HF (HR 1.62; [1.33–1.97]), and hard CVD (HR 1.30; [1.13–1.51], all p<0.001). Adjusted models with the LACI showed significant improvement in model discrimination and reclassification when compared to currently used standard models used to predict the incidence of AF (C-statistic=0.82 vs. 0.79; NRI=0.325; IDI=0.036), HF (C-statistic=0.84 vs. 0.81; NRI=0.571; IDI=0.023), hard CVD (C-statistic=0.78 vs. 0.76; NRI=0.229; IDI=0.012).

Conclusion

In a multi-ethnic population of pre- and post-menopausal women, the LACI is an independent predictor of HF, AF, and hard CVD. In both pre- and post-menopausal women, the LACI has an incremental prognostic value for predicting cardiovascular events over traditional risk factors and sex hormone levels.

ClinicalTrials: gov Identifier: NCT00005487

Funding Acknowledgement

Type of funding sources: None.

KLMab-1: An Anti-human KLRG1 Monoclonal Antibody for Immunocytochemistry

Immune checkpoint molecules have received attention as targets of cancer immunotherapy. Killer cell lectin-like receptor subfamily G member 1 (KLRG1) is one of the immune checkpoint molecules expressed in CD4⁺ T, CD8⁺ T, and natural killer (NK) cells. KLRG1 exhibits antiviral and antitumor immunity, and its expression in T and NK cells is upregulated by viral infectious diseases and some tumors. Thus, monoclonal antibodies (mAbs) for KLRG1 would be useful tools for the diagnosis and immunotherapy against viral infectious diseases and cancers. We have developed anti-human KLRG1 (hKLRG1) mAb (clone KLMab-1, mouse IgG₁, kappa) by the Cell-Based Immunization and Screening method. We have also demonstrated that KLMab-1 recognizes both exogenous and endogenous hKLRG1 in flow cytometry. In this study, we first showed that KLMab-1 and its recombinant mAb (recKLMab-1) bound to exogenous hKLRG1 overexpressed in Chinese hamster ovary (CHO)-K1 cells, but not in parental CHO-K1 cells, in immunocytochemistry. We next showed that both mAbs detected endogenous hKLRG1 expressed in human NK cells. These results demonstrate that KLMab-1 and recKLMab-1 are available for immunocytochemistry.

Efficacy of cancer-specific anti-podoplanin CAR-T cells and oncolytic herpes virus G47Δ combination therapy against glioblastoma

Glioblastoma is a devastating malignant brain tumor with a poor prognosis despite standard therapy. Podoplanin (PDPN), a type I transmembrane mucin-like glycoprotein that is overexpressed in various cancers, is a potential therapeutic target for the treatment of glioblastoma. We previously reported the efficacy of chimeric antigen receptor (CAR)-T cells using an anti-pan-PDPN monoclonal antibody (mAb; NZ-1)-based third-generation CAR in a xenograft mouse model. However, NZ-1 also reacted with PDPN-expressing normal cells, such as lymphatic endothelial cells, pulmonary alveolar type I cells, and podocytes. To overcome possible on-target-off-tumor effects, we produced a cancer-specific mAb (CasMab, LpMab-2)-based CAR. LpMab-2 (Lp2) reacted with PDPN-expressing cancer cells but not with normal cells. In this study, Lp2-CAR-transduced T cells (Lp2-CAR-T) specifically targeted PDPN-expressing glioma cells while sparing the PDPN-expressing normal cells. Lp2-CAR-T also killed patient-derived glioma stem cells, demonstrating its clinical potential against glioblastoma. Systemic injection of Lp2-CAR-T cells inhibited the growth of a subcutaneous glioma xenograft model in immunodeficient mice. Combination therapy with Lp2-CAR-T and oncolytic virus G47Δ, a third-generation recombinant herpes simplex virus (HSV)-1, further inhibited the tumor growth and improved survival. These findings indicate that the combination therapy of Lp2-CAR-T cells and G47Δ may be a promising approach to treat glioblastoma.

Mechanistic insights into intramembrane proteolysis by E. coli site-2 protease homolog RseP

Site-2 proteases are a conserved family of intramembrane proteases that cleave transmembrane substrates to regulate signal transduction and maintain proteostasis. Here, we elucidated crystal structures of inhibitor-bound forms of bacterial site-2 proteases including Escherichia coli RseP. Structure-based chemical modification and cross-linking experiments indicated that the RseP domains surrounding the active center undergo conformational changes to expose the substrate-binding site, suggesting that RseP has a gating mechanism to regulate substrate entry. Furthermore, mutational analysis suggests that a conserved electrostatic linkage between the transmembrane and peripheral membrane-associated domains mediates the conformational changes. In vivo cleavage assays also support that the substrate transmembrane helix is unwound by strand addition to the intramembrane β sheet of RseP and is clamped by a conserved asparagine residue at the active center for efficient cleavage. This mechanism underlying the substrate binding, i.e., unwinding and clamping, appears common across distinct families of intramembrane proteases that cleave transmembrane segments.

Epitope Mapping of an Anti-elephant Podoplanin Monoclonal Antibody (PMab-295) Using Enzyme-Linked Immunosorbent Assay

Podoplanin (PDPN) is a marker of lung type I alveolar cells, kidney podocytes, and lymphatic endothelial cells. The overexpression of PDPN contributes to the malignant progression of tumors. Therefore, the development of anti-PDPN monoclonal antibodies (mAbs) to animals is essential to evaluate the pathogenesis and cellular functions. Using peptide immunization, we previously developed an anti-elephant PDPN (elePDPN) mAb, PMab-295, which is useful for flow cytometry, Western blotting, and immunohistochemistry. In this study, we determined the critical epitope of PMab-295 by enzyme-linked immunosorbent assay (ELISA). We performed ELISA with the alanine-substituted peptides of elePDPN extracellular domain (amino acids 38-51), and found that PMab-295 did not recognize the alanine-substituted peptides of M41A, P44A, and E47A. Furthermore, these peptides could not inhibit the recognition of PMab-295 to elePDPN-expressing cells by flow cytometry and immunohistochemistry. The results indicate that the binding epitope of PMab-295 includes Met41, Pro44, and Glu47 of elePDPN.

Development of an Anti-human CCR2 Monoclonal Antibody (C2Mab-9) by N-Terminal Peptide Immunization

The CC chemokine receptor type-2 (CCR2) is one of the members of the G protein-coupled receptor superfamily, which are expressed on the cell surface of immune and tumor cells. CCR2 binds to the C-C motif chemokine ligand 2 (CCL2)/monocyte chemoattractant protein-1 (MCP-1), which is produced by various cells, including tumor and immune-related cells. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CCR2 has been desired for treatment and diagnosis. In this study, we established a specific antihuman CCR2 (hCCR2) mAb, C₂Mab-9 (mouse IgG₁, kappa), using the synthetic peptide immunization method. Flow cytometric and immunocytochemical results showed that C₂Mab-9 reacted with hCCR2-expressing U937 (human histiocytic lymphoma) and natural killer cells. Furthermore, C₂Mab-9 showed the moderate binding affinity for both cells. Conclusively, C₂Mab-9 can be a useful tool for analyzing hCCR2-related biological responses.

Identification of the Binding Epitope of an Anti-mouse CCR4 Monoclonal Antibody, C4Mab-1

C-C chemokine receptor 4 (CCR4) is one of G protein-coupled receptors, and interacts with chemokines, CCL17 and CCL22. CCR4 is expressed on T cells such as helper T type 2 cells, regulatory T cells, and interleukin 17-producing T helper cells. CCR4 is associated with T cells trafficking into the tumor microenvironment, and is associated with tumor progression or metastasis. Therefore, CCR4 may be a potential therapeutic option for T cell malignancies. C₄Mab-1 is a novel anti-mouse CCR4 (mCCR4) monoclonal antibody produced by mCCR4 N-terminal peptide immunization. C₄Mab-1 is useful for flow cytometric analysis. In this study, we conducted the epitope mapping of C₄Mab-1 using enzyme-linked immunosorbent assay (ELISA) and peptide blocking assay. The result of ELISA indicated that Thr7, Asp8, and Gln11 of mCCR4 are the critical amino acids for the C₄Mab-1 binding. Furthermore, peptide blocking assay by flow cytometry showed that Thr7, Asp8, and Gln11 of mCCR4 are essential for C₄Mab-1 binding to mCCR4-overexpressed Chinese hamster ovary-K1 (CHO/mCCR4) cells, and Val6, Thr9, and Thr10 are involved in the C₄Mab-1 binding to CHO/mCCR4 cells. These results indicate that the critical binding epitope of C₄Mab-1 includes Thr7, Asp8, and Gln11 of mCCR4.

Development of a Monoclonal Antibody PMab-295 Against Elephant Podoplanin

Podoplanin (PDPN) is an essential marker of lung type I alveolar cells, kidney podocytes, and lymphatic endothelial cells. Monoclonal antibodies (mAbs) that can specifically recognize PDPN in immunohistochemistry are important to analyze the development of tissues and the pathogenesis of diseases, including cancers. We have developed anti-PDPN mAbs against many animal species; however, mAbs that can recognize elephant-derived membrane proteins and distinguish the specific cell types in immunohistochemistry are limited. In this study, a novel anti-elephant PDPN (elePDPN) mAb, PMab-295 (IgG₁, kappa), was established using the peptide immunization method. PMab-295 recognized both elePDPN-overexpressed Chinese hamster ovary (CHO)-K1 cells and endogenous elePDPN-expressed LACF-NaNaI cells by flow cytometry and western blotting. Kinetic analyses using flow cytometry showed that the K_D of PMab-295 for CHO/elePDPN was 1.5 × 10^-8 M. Furthermore, PMab-295 detected elePDPN-expressing cells using immunohistochemistry. These results showed the usefulness of PMab-295 to investigate the molecular function of elePDPN and the pathogenesis of diseases.

Defucosylated mouse‑dog chimeric anti‑HER2 monoclonal antibody exerts antitumor activities in mouse xenograft models of canine tumors

Human epidermal growth factor receptor 2 (HER2) overexpression has been reported in various types of cancer, including breast, gastric, lung, colorectal and pancreatic cancer. A humanized anti-HER2 monoclonal antibody (mAb), trastuzumab, has been shown to improve survival of patients in HER2-positive breast and gastric cancer. An anti-HER2 mAb, H₂Mab-77 (mouse IgG₁, kappa) was previously developed. In the present study, a defucosylated version of mouse-dog chimeric anti-HER2 mAb (H77Bf) was generated. H77Bf possesses a high binding-affinity [a dissociation constant (K_D): 7.5×10⁻¹⁰ M, as determined by flow cytometric analysis] for dog HER2-overexpressed CHO-K1 (CHO/dHER2) cells. H77Bf highly exerted antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) for CHO/dHER2 cells by canine mononuclear cells and complement, respectively. Moreover, administration of H77Bf significantly suppressed the development of CHO/dHER2 ×enograft tumor in mice compared with the control dog IgG. H77Bf also possesses a high binding-affinity (K_D: 7.2×10⁻¹⁰ M) for a canine mammary gland tumor cell line (SNP), and showed high ADCC and CDC activities for SNP cells. Intraperitoneal administration of H77Bf in mouse xenograft models of SNP significantly suppressed the development of SNP xenograft tumors compared with the control dog IgG. These results indicated that H77Bf exerts antitumor activities against dHER2-positive canine cancers, and could be valuable treatment regimen for canine cancers.

Improved anti-solid tumor response by humanized anti-podoplanin chimeric antigen receptor transduced human cytotoxic T cells in an animal model

Recently, research has been conducted with chimeric antigen receptor (CAR)-T cells to improve efficacy against solid tumors. Humanized CAR improved the long-term survival of CAR-T cells in patients' peripheral blood, resulting in increased therapeutic efficacy. Therefore, the humanization of the CAR-gene sequence is considered an effective method. Podoplanin (PDPN) is a glycosylated transmembrane protein that is highly expressed in solid tumors and is associated with poor prognosis in patients with cancer. Therefore, PDPN is considered a biomarker and good target for cancer treatment with CAR-T cells. Previously, an anti-PDPN CAR was generated from a conventional non-humanized antibody-NZ-1, the only anti-PDPN antibody for which a CAR was produced. In this study, we investigated other anti-PDPN CARs from the antibody NZ-27, or humanized NZ-1, to enhance the therapeutic potential of CAR-T cells. The CAR signal intensity was enhanced by the efficient expression of CAR proteins on the T-cell surface of NZ-27 CAR-T cells, which show tumor-specific cytotoxicity, proinflammatory cytokine production, and anti-tumor activity against PDPN-expressing tumor xenografts in mice that were significantly better than those in non-humanized NZ-1 CAR-T cells. This article is protected by copyright. All rights reserved.

Epitope Mapping of an Anti-Chinese/Golden Hamster Podoplanin Monoclonal Antibody

Chinese hamster (Cricetulus griseus) and golden hamster (Mesocricetus auratus) are important animal models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, which affect several organs, including respiratory tract, lung, and kidney. Podoplanin (PDPN) is a marker of lung type I alveolar cells, kidney podocytes, and lymphatic endothelial cells. The development of anti-PDPN monoclonal antibodies (mAbs) for these animals is essential to evaluate the pathogenesis by SARS-CoV-2 infections. Using the Cell-Based Immunization and Screening method, we previously developed an anti-Chinese hamster PDPN (ChamPDPN) mAb, PMab-281 (mouse IgG₃, kappa), and further changed its subclass into IgG_2a (281-mG_2a-f), both of which can recognize not only ChamPDPN but also golden hamster PDPN (GhamPDPN) by flow cytometry and immunohistochemistry. In this study, we examined the critical epitope of 281-mG_2a-f, using enzyme-linked immunosorbent assay (ELISA) with synthesized peptides. First, we performed ELISA with peptides derived from ChamPDPN and GhamPDPN extracellular domain, and found that 281-mG_2a-f reacted with the peptides, which commonly possess the KIPFEELxT sequence. Next, we analyzed the reaction with the alanine-substituted mutants, and revealed that 281-mG_2a-f did not recognize the alanine-substituted peptides of I75A, F77A, and E79A of ChamPDPN. Furthermore, these peptides could not inhibit the recognition of 281-mG_2a-f to ChamPDPN-expressing cells by flow cytometry. The results indicate that the binding epitope of 281-mG_2a-f includes Ile75, Phe77, and Glu79 of ChamPDPN, which are shared with GhamPDPN.

Defucosylated Anti-Epidermal Growth Factor Receptor Monoclonal Antibody Exerted Antitumor Activities in Mouse Xenograft Models of Canine Mammary Gland Tumor

The epidermal growth factor receptor (EGFR) contributes to tumor malignancy through gene amplification and/or protein overexpression. In our previous study, we developed an anti-human EGFR (hEGFR) monoclonal antibody, clone EMab-134 (mouse IgG₁, kappa), which specifically detects both hEGFR and dog EGFR (dEGFR). The defucosylated mouse IgG_2a version of EMab-134 (134-mG_2a-f) exhibits antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in dEGFR-overexpressed Chinese hamster ovary-K1 (CHO/dEGFR) cells and antitumor activities in mouse xenografts of CHO/dEGFR cells. In this study, the reactivity of 134-mG_2a-f against a canine mammary gland tumor cell line (SNP) was examined by flow cytometry and immunocytochemistry. Furthermore, 134-mG_2a-f highly exerted ADCC and CDC for SNP. The administration of 134-mG_2a-f significantly suppressed the SNP xenograft growth. These results suggest that 134-mG_2a-f exerts antitumor effects against dEGFR-expressing canine mammary gland tumors, and could be valuable as part of an antibody treatment regimen for them.

Epitope Mapping of the Anti-Human CCR2 Monoclonal Antibody C2Mab-9

CC chemokine receptor type-2 (CCR2) belongs to the G protein-coupled receptors superfamily, localized on cell surface of some immune-related cells, including monocytes and macrophages. CCR2 and its ligand CCL2 are involved in the progression of various diseases such as cancers. Therefore, CCR2-targeted monoclonal antibodies (mAbs) are needed for treatment and diagnosis. Previously, we successfully developed an anti-human CCR2 (hCCR2) mAb, C₂Mab-9 (mouse IgG₁, kappa), which is applicable for flow cytometry and immunocytochemistry. In this study, we investigated the critical epitope of C₂Mab-9. We conducted enzyme-linked immunosorbent assay (ELISA) using several N-terminal peptides of hCCR2, and demonstrated that C₂Mab-9 recognizes 11-29 and 21-39 amino acids of hCCR2. We further performed ELISA using 20 peptides, which include alanine substitution of hCCR2. C₂Mab-9 lost the reaction to the alanine-substituted peptides of F23A, F24A, D25A, Y26A, and D27A. Among them, F23A, F24A, D25A, and Y26A did not block the C₂Mab-9 reaction with U937 cells in flow cytometry. These results indicate that the critical binding epitope of C₂Mab-9 includes Phe23, Phe24, Asp25, and Tyr26.

Exploration of serum biomarkers in dogs with malignant melanoma receiving anti-PD-L1 therapy and potential of COX-2 inhibition for combination therapy

Immune checkpoint inhibitors (ICIs) such as anti-PD-L1 antibodies are widely used to treat human cancers, and growing evidence suggests that ICIs are promising treatments for canine malignancies. However, only some canine oral malignant melanoma (OMM) cases respond to ICIs. To explore biomarkers predictive of survival in dogs with pulmonary metastatic OMM receiving the anti-PD-L1 antibody c4G12 (n = 27), serum concentrations of prostaglandin E2 (PGE2), cytokines, chemokines, and growth factors were measured prior to treatment initiation. Among 12 factors tested, PGE2, interleukin (IL)-12p40, IL-8, monocyte chemotactic protein-1 (MCP-1), and stem cell factor (SCF) were higher in OMM dogs compared to healthy dogs (n = 8). Further, lower baseline serum PGE2, MCP-1, and vascular endothelial growth factor (VEGF)-A concentrations as well as higher IL-2, IL-12, and SCF concentrations predicted prolonged overall survival. These observations suggest that PGE2 confers resistance against anti-PD-L1 therapy through immunosuppression and thus is a candidate target for combination therapy. Indeed, PGE2 suppressed IL-2 and interferon (IFN)-γ production by stimulated canine peripheral blood mononuclear cells (PBMCs), while inhibition of PGE2 biosynthesis using the COX-2 inhibitor meloxicam in combination with c4G12 enhanced Th1 cytokine production by PBMCs. Thus, serum PGE2 may be predictive of c4G12 treatment response, and concomitant use of COX-2 inhibitors may enhance ICI antitumor efficacy.

TgMab-2: An Anti-human T Cell Immunoglobulin and Immunoreceptor Tyrosine-Based Inhibitory Motif Domain Monoclonal Antibody for Immunocytochemistry

T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is one of the immune checkpoint molecules. TIGIT is expressed in T or natural killer (NK) cells and is upregulated in several cancers. Because TIGIT suppresses the antitumor activity of the T or NK cells by binding to its ligand, such as CD155, CD112, and CD113, TIGIT can be a molecular marker or a therapeutic target for cancer immunotherapy. We previously developed an anti-human TIGIT (hTIGIT) monoclonal antibody (mAb; clone TgMab-2; mouse IgG₁, kappa) by the Cell-Based Immunization and Screening method. TgMab-2 binds to hTIGIT with high binding affinity in flow cytometry. In this study, we investigated the availability of TgMab-2 and its recombinant mAb (recTgMab-2) in immunocytochemistry. We found that TgMab-2 and recTgMab-2 bind to hTIGIT-overexpressed Chinese hamster ovary (CHO)-K1 cells, but not parental CHO-K1 cells, indicating that both mAbs specifically recognize hTIGIT. Furthermore, both mAbs recognized endogenous hTIGIT expressed in human NK cells in immunocytochemistry. These results demonstrate that TgMab-2 and recTgMab-2 are applicable for immunocytochemistry against hTIGIT.

Cx6Mab-1: A Novel Anti-Mouse CXCR6 Monoclonal Antibody Established by N-Terminal Peptide Immunization

The CXC chemokine receptor 6 (CXCR6) is a member of the G protein-coupled receptor family that is highly expressed in helper T type 1 cells, natural killer cells, cytotoxic T lymphocytes, and various type of cells in tumor microenvironment (TME). CXCR6 has been proposed as a therapeutic target against tumors through regulation of the tumor TME. In this study, we developed specific and sensitive monoclonal antibodies (mAbs) for mouse CXCR6 (mCXCR6), which are useful for flow cytometry and Western blotting by N-terminal peptide immunization into rat. The established anti-mCXCR6 mAb, Cx₆Mab-1 (rat IgG₁, kappa), reacted with not only mCXCR6-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR6) but also mCXCR6-endogenously expressed cell lines, such as P388 (mouse lymphoid neoplasm) and J774-1 (mouse macrophage-like) through flow cytometry. Kinetic analyses using flow cytometry indicated that the dissociation constants (K_D) of Cx₆Mab-1 for CHO/mCXCR6, P388, and J774-1 cells were 1.7 × 10^-9 M, 3.4 × 10^-7 M, and 3.8 × 10^-7 M, respectively. Furthermore, Cx₆Mab-1 could detect endogenous mCXCR6 in P388 and J774-1 cells by Western blotting. These results indicated that Cx₆Mab-1 is useful for detecting mCXCR6 by flow cytometry and Western blotting, and provides a possibility for targeting CXCR6-expressing cells in vivo experiments.

Effect of the duration of previous osteoporosis treatment on the effect of romosozumab treatment

The effect of romosozumab is affected by previous osteoporosis treatment. Here we showed that the duration of the previous treatment just before romosozumab affects the therapeutic effect of romosozumab. Using denosumab and oral bisphosphonates for more than 1 year attenuates the effect of romosozumab.

INTRODUCTION

As an anti-sclerostin antibody, romosozumab suppresses bone resorption and stimulates bone formation. We investigated whether the effectiveness of 12 months of romosozumab treatment depended on the duration of previous treatment with teriparatide, denosumab, or oral bisphosphonates.

METHODS

In total, 259 osteoporosis patients received subcutaneous injections of romosozumab (210 mg) every 4 weeks during 2019 and 2020. This study was designed as a pre-post comparison. The end points were the percent changes of bone mineral density (BMD) after 12 months of romosozumab treatment. The patients were divided into seven groups depending on the type and duration of previous treatment before starting romosozumab as follows: non-previous treatment group, change from teriparatide used for 1 year or less/more than 1 year, change from denosumab used for 1 year or less/more than 1 year, and change from oral bisphosphonates used for 1 year or less/more than 1 year.

RESULTS

The effects of previous treatment with teriparatide on the effectiveness of 12-month romosozumab did not clearly depend on the duration of treatment (p > 0.05). In contrast, the effects of previous treatments with denosumab or oral bisphosphonates on the effectiveness of 12-month romosozumab depended on the previous treatment duration, which was reflected by the differences in percent change of the spine BMD (both p < 0.05), however, there were no significant differences in the percent change of the total hip BMD (both p > 0.05).

CONCLUSION

The duration of the previous treatment affected the effectiveness of romosozumab. Using denosumab and oral bisphosphonate for more than 1 year attenuated the effect of romosozumab.

mTORC1-independent translation control in mammalian cells by methionine adenosyltransferase 2A and S-adenosylmethionine

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (SAM). As the sole methyl-donor for methylation of DNA, RNA, and proteins, SAM levels affect gene expression by changing methylation patterns. Expression of MAT2A, the catalytic subunit of isozyme MAT2, is positively correlated with proliferation of cancer cells; however, how MAT2A promotes cell proliferation is largely unknown. Given that the protein synthesis is induced in proliferating cells and that RNA and protein components of translation machinery are methylated, we tested here whether MAT2 and SAM are coupled with protein synthesis. By measuring ongoing protein translation via puromycin labeling, we revealed that MAT2A depletion or chemical inhibition reduced protein synthesis in HeLa and Hepa1 cells. Furthermore, overexpression of MAT2A enhanced protein synthesis, indicating that SAM is limiting under normal culture conditions. In addition, MAT2 inhibition did not accompany reduction in mechanistic target of rapamycin complex 1 activity but nevertheless reduced polysome formation. Polysome-bound RNA sequencing revealed that MAT2 inhibition decreased translation efficiency of some fraction of mRNAs. MAT2A was also found to interact with the proteins involved in rRNA processing and ribosome biogenesis; depletion or inhibition of MAT2 reduced 18S rRNA processing. Finally, quantitative mass spectrometry revealed that some translation factors were dynamically methylated in response to the activity of MAT2A. These observations suggest that cells possess an mTOR-independent regulatory mechanism that tunes translation in response to the levels of SAM. Such a system may acclimate cells for survival when SAM synthesis is reduced, whereas it may support proliferation when SAM is sufficient.

Establishment of Novel Anti-Mouse CCR3 Monoclonal Antibodies (C3Mab-6 and C3Mab-7) by N-terminal Peptide Immunization

The CC chemokine receptor 3 (CCR3) is a member of the G protein-coupled receptor family that is highly expressed in eosinophils and basophils. CCR3 has been proposed as a therapeutic target for human immunodeficiency virus and allergy diagnosis. Therefore, in this study, we developed specific and sensitive monoclonal antibodies (mAbs) for mouse CCR3 (mCCR3), which are useful for flow cytometry by peptide immunization. The established anti-mCCR3 mAbs, C₃Mab-6 (rat IgG₁, kappa) and C₃Mab-7 (rat IgG₁, kappa), reacted with mCCR3-overexpressed Chinese hamster ovary-K1 (CHO/mCCR3), in addition to mCCR3-endogenously expressed cell lines, such as P388 (mouse lymphoid neoplasma) and J774-1 (mouse macrophage-like) through flow cytometry. Kinetic analyses using flow cytometry indicated that the dissociation constants (K_Ds) of C₃Mab-6 for CHO/mCCR3, P388, and J774-1 cells were 8.7 × 10^-9 M, 1.4 × 10^-7 M, and 1.7 × 10^-7 M, respectively, whereas the K_Ds of C₃Mab-7 for these cell lines were 3.7 × 10^-9 M, 5.1 × 10^-7 M, and 3.1 × 10^-7 M, respectively. Results also indicated that C₃Mab-6 and C₃Mab-7 are useful for detecting cells expressing CCR3 through flow cytometry, thereby making them potentially beneficial for treating CCR3-expressing cells.

C9Mab-1: An Anti-Mouse CCR9 Monoclonal Antibody for Immunocytochemistry

C-C motif chemokine receptor 9 (CCR9) is a G protein-coupled receptor, which is highly expressed in T-lymphocytes and different cancer cells. CCR9 aggravates immune diseases and cancer progression and is considered a biomarker and a therapeutic target of diseases. The development of specific monoclonal antibody (mAbs) for human CCR9 (hCCR9) is required to diagnose and treat immune diseases and cancers. Previously, we established the cell-based immunization and screening (CBIS) method, which does not need purified target proteins. Anti-hCCR9 mAb (clone C₉Mab-1; mouse IgG₁, kappa) was also developed using the CBIS method. C₉Mab-1 is usable for flow cytometry against exogenously and endogenously expressing hCCR9. This study showed that C₉Mab-1 and its recombinant antibody (recC₉Mab-1) specifically detected exogenous hCCR9 stably overexpressed in Chinese hamster ovary (CHO)-K1 cells and endogenous hCCR9 expressed in a human T-lymphoblastic leukemia cell line MOLT-4 cells through immunocytochemistry. This study provides a new application of C₉Mab-1 and recC₉Mab-1 in immunocytochemistry.