Cellular senescence of granulosa cells in the pathogenesis of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age, but its pathology has not been fully characterized and the optimal treatment strategy remains unclear. Cellular senescence is a permanent state of cell-cycle arrest that can be induced by multiple stresses. Senescent cells contribute to the pathogenesis of various diseases, owing to an alteration in secretory profile, termed 'senescence-associated secretory phenotype' (SASP), including with respect to pro-inflammatory cytokines. Senolytics, a class of drugs that selectively eliminate senescent cells, are now being used clinically, and a combination of dasatinib and quercetin (DQ) has been extensively used as a senolytic. We aimed to investigate whether cellular senescence is involved in the pathology of PCOS and whether DQ treatment has beneficial effects in patients with PCOS. We obtained ovaries from patients with or without PCOS, and established a mouse model of PCOS by injecting dehydroepiandrosterone. The expression of the senescence markers p16INK4a, p21, p53, γH2AX, and senescence-associated ß-galactosidase (SA-ß-gal); and the SASP-related factor interleukin (IL)-6; were significantly higher in the ovaries of patients with PCOS and PCOS mice than in controls. To evaluate the effects of hyperandrogenism and DQ on cellular senescence in vitro, we stimulated cultured human granulosa cells (GCs) with testosterone and treated them with DQ. The expression of markers of senescence and a SASP-related factor was increased by testosterone, and DQ reduced this increase. DQ reduced the expression of markers of senescence and a SASP-related factor in the ovaries of PCOS mice and improved their morphology. These results indicate that cellular senescence occurs in PCOS. Hyperandrogenism causes cellular senescence in GCs in PCOS and senolytic treatment reduces the accumulation of senescent GCs and improves ovarian morphology under hyperandrogenism. Thus, DQ might represent a novel therapy for PCOS.

Effects of the prenatal and postnatal nurturing environment on the phenotype and gut microbiota of mice with polycystic ovary syndrome induced by prenatal androgen exposure: a cross-fostering study.

The gut microbiome is implicated in the pathogenesis of polycystic ovary syndrome (PCOS), and prenatal androgen exposure is involved in the development of PCOS in later life. Our previous study of a mouse model of PCOS induced by prenatal dihydrotestosterone (DHT) exposure showed that the reproductive phenotype of PCOS appears from puberty, followed by the appearance of the metabolic phenotype after young adulthood, while changes in the gut microbiota was already apparent before puberty. To determine whether the prenatal or postnatal nurturing environment primarily contributes to these changes that characterize prenatally androgenized (PNA) offspring, we used a cross-fostering model to evaluate the effects of changes in the postnatal early-life environment of PNA offspring on the development of PCOS-like phenotypes and alterations in the gut microbiota in later life. Female PNA offspring fostered by normal dams (exposed to an abnormal prenatal environment only, fostered PNA) exhibited less marked PCOS-like phenotypes than PNA offspring, especially with respect to the metabolic phenotype. The gut microbiota of the fostered PNA offspring was similar to that of controls before adolescence, but differences between the fostered PNA and control groups became apparent after young adulthood. In conclusion, both prenatal androgen exposure and the postnatal early-life environment created by the DHT injection of mothers contribute to the development of PCOS-like phenotypes and the alterations in the gut microbiota that characterize PNA offspring. Thus, both the pre- and postnatal environments represent targets for the prevention of PCOS and the associated alteration in the gut microbiota in later life.

Non-catalytic role of phosphoinositide 3-kinase in mesenchymal cell migration through non-canonical induction of p85ß/AP2-mediated endocytosis.

Class IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable these multifaceted roles, the catalytic subunit p110 utilizes the multi-domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, its product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and their relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains AP2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and increase both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.

The Association between Endometriosis and Obstructive Müllerian Anomalies.

It is unclear whether clinical background differs between endometriosis in adolescent patients with obstructive Müllerian anomalies and those without anomalies. The aim of the study is to identify the difference in clinical characteristics of endometriosis in patients with or without obstructive Müllerian anomalies. The study involved 12 patients aged under 24 years old who underwent primary surgery for obstructive Müllerian anomalies and 31 patients aged under 24 years old who underwent surgery for ovarian endometrioma. A total of 6 out of 12 cases with obstructive Müllerian anomalies developed endometriosis (4 Herlyn-Werner-Wunderlich syndrome, 2 non-communicating functional uterine horn, 2 cervical aplasia). The age at surgery was significantly younger in endometriosis with obstructive Müllerian anomalies, compared with those without obstructive Müllerian anomalies (17.8 ± 4.4 vs. 23.1 ± 1.3, p = 0.0007). The rate of endometrioma was 50.0% and the rate of hydrosalpinx was significantly higher (66.7% vs. 0%, p = 0.0002) in the group of obstructive Müllerian anomalies. The recurrence rate of endometriosis was 20.0% in the group of anomalies and 25.9% in the group of those without anomalies. Adolescent patients with obstructive Müllerian anomalies more easily developed endometriosis and co-occurred with higher rate of hematosalipinx.

Toward an application of automatic evaluation system for central facial palsy using two simple evaluation indices in emergency medicine.

A stroke is a medical emergency and thus requires immediate treatment. Paramedics should accurately assess suspected stroke patients and promptly transport them to a hospital with stroke care facilities; however, current assessment procedures rely on subjective visual assessment. We aim to develop an automatic evaluation system for central facial palsy (CFP) that uses RGB cameras installed in an ambulance. This paper presents two evaluation indices, namely the symmetry of mouth movement and the difference in mouth shape, respectively, extracted from video frames. These evaluation indices allow us to quantitatively evaluate the degree of facial palsy. A classification model based on these indices can discriminate patients with CFP. The results of experiments using our dataset show that the values of the two evaluation indices are significantly different between healthy subjects and CFP patients. Furthermore, our classification model achieved an area under the curve of 0.847. This study demonstrates that the proposed automatic evaluation system has great potential for quantitatively assessing CFP patients based on two evaluation indices.

Epidemiology and patterns of empiric antimicrobial therapy practice in patients with community-onset sepsis using data from a Japanese nationwide medical claims database-the Japan Sepsis Alliance (JaSA) study group.

Objectives: We aimed to describe empiric antimicrobial options for patients with community-onset sepsis using nationwide real-world data from Japan. Methods: This retrospective cohort study used nationwide Japanese data from a medical reimbursement system database. Patients aged ≥20 years with both presumed infections and acute organ dysfunction who were admitted to hospitals from the outpatient department or emergency department between 2010 and 2017 were enrolled. We described the initial choices of antimicrobials for patients with sepsis stratified by intensive care unit (ICU) or ward. Results: There were 1,195,741 patients with community-onset sepsis; of these, 1,068,719 and 127,022 patients were admitted to the wards and ICU, respectively. Third-generation cephalosporins and carbapenem were most commonly used for patients with community-onset sepsis. We found that 1.7% and 6.0% of patients initially used antimicrobials for methicillin-resistant Staphylococcus aureus coverage in the wards and ICU, respectively. Although half of the patients initially used antipseudomonal agents, only a few patients used a combination of antipseudomonal agents. Moreover, few patients initially used a combination of antimicrobials to treat methicillin-resistant Staphylococcus aureus and Pseudomonas sp. Conclusion: Third-generation cephalosporins and carbapenem were most frequently used for patients with sepsis. A combination therapy of antimicrobials for drug-resistant bacteria coverage was rarely provided to these patients.

Type 1 immunity enables neonatal thymic ILC1 production.

Acute thymic atrophy occurs following type 1 inflammatory conditions such as viral infection and sepsis, resulting in cell death and disruption of T cell development. However, the impact type 1 immunity has on thymic-resident innate lymphoid cells (ILCs) remains unclear. Single-cell RNA sequencing revealed neonatal thymic-resident type 1 ILCs (ILC1s) as a unique and immature subset compared to ILC1s in other primary lymphoid organs. Culturing murine neonatal thymic lobes with the type 1 cytokines interleukin-12 (IL-12) and IL-18 resulted in a rapid expansion and thymic egress of KLRG1+CXCR6+ cytotoxic ILC1s. Live imaging showed the subcapsular thymic localization and exit of ILC1s following IL-12 + IL-18 stimulation. Similarly, murine cytomegalovirus infection in neonates resulted in thymic atrophy and subcapsular localization of thymic-resident ILC1s. Neonatal thymic grafting revealed that type 1 inflammation enhances the homing of cytokine-producing thymus-derived ILC1s to the liver and peritoneal cavity. Together, we show that type 1 immunity promotes the expansion and peripheral homing of thymic-derived ILC1s.

Machine-learning model for predicting oliguria in critically ill patients.

This retrospective cohort study aimed to develop and evaluate a machine-learning algorithm for predicting oliguria, a sign of acute kidney injury (AKI). To this end, electronic health record data from consecutive patients admitted to the intensive care unit (ICU) between 2010 and 2019 were used and oliguria was defined as a urine output of less than 0.5 mL/kg/h. Furthermore, a light-gradient boosting machine was used for model development. Among the 9,241 patients who participated in the study, the proportions of patients with urine output < 0.5 mL/kg/h for 6 h and with AKI during the ICU stay were 27.4% and 30.2%, respectively. The area under the curve (AUC) values provided by the prediction algorithm for the onset of oliguria at 6 h and 72 h using 28 clinically relevant variables were 0.964 (a 95% confidence interval (CI) of 0.963-0.965) and 0.916 (a 95% CI of 0.914-0.918), respectively. The Shapley additive explanation analysis for predicting oliguria at 6 h identified urine values, severity scores, serum creatinine, oxygen partial pressure, fibrinogen/fibrin degradation products, interleukin-6, and peripheral temperature as important variables. Thus, this study demonstrates that a machine-learning algorithm can accurately predict oliguria onset in ICU patients, suggesting the importance of oliguria in the early diagnosis and optimal management of AKI.

Association between hospital spending and in-hospital mortality of patients with sepsis based on a Japanese nationwide medical claims database study.

Background: The effect of hospital spending on the mortality rate of patients with sepsis has not yet been fully elucidated. We hypothesized that hospitals that consume more medical resources would have lower mortality rates among patients with sepsis. Methods: This retrospective study used administrative data from 2010 to 2017. The enrolled hospitals were divided into quartiles based on average daily medical cost per sepsis case. The primary and secondary outcomes were the average in-hospital mortality rate of patients with sepsis and the effective cost per survivor among the enrolled hospitals, respectively. A multiple regression model was used to determine the significance of the differences among hospital categories to adjust for baseline imbalances. Results: Among 997 hospitals enrolled in this study, the crude in-hospital mortality rates were 15.7% and 13.2% in the lowest and highest quartiles of hospital spending, respectively. After adjusting for confounding factors, the highest hospital spending group demonstrated a significantly lower in-hospital mortality rate than the lowest hospital spending group (coefficient = -0.025, 95% confidence interval [CI] -0.034 to -0.015; p < 0.0001). Similarly, the highest hospital spending group was associated with a significantly higher effective cost per survivor than the lowest hospital spending group (coefficient = 77.7, 95% CI 73.1 to 82.3; p < 0.0001). In subgroup analyses, hospitals with a small or medium number of beds demonstrated a consistent pattern with the primary test, whereas those with a large number of beds or academic affiliations displayed no association. Conclusions: Using a nationwide Japanese medical claims database, this study indicated that hospitals with greater expenditures were associated with a superior survival rate and a higher effective cost per survivor in patients with sepsis than those with lower expenditures. In contrast, no correlations between hospital spending and mortality were observed in hospitals with a large number of beds or academic affiliations.

The Role of Cellular Senescence in Cyclophosphamide-Induced Primary Ovarian Insufficiency.

Young female cancer patients can develop chemotherapy-induced primary ovarian insufficiency (POI). Cyclophosphamide (Cy) is one of the most widely used chemotherapies and has the highest risk of damaging the ovaries. Recent studies elucidated the pivotal roles of cellular senescence, which is characterized by permanent cell growth arrest, in the pathologies of various diseases. Moreover, several promising senolytics, including dasatinib and quercetin (DQ), which remove senescent cells, are being developed. In the present study, we investigated whether cellular senescence is involved in Cy-induced POI and whether DQ treatment rescues Cy-induced ovarian damage. Expression of the cellular senescence markers p16, p21, p53, and γH2AX was upregulated in granulosa cells of POI mice and in human granulosa cells treated with Cy, which was abrogated by DQ treatment. The administration of Cy decreased the numbers of primordial and primary follicles, with a concomitant increase in the ratio of growing to dormant follicles, which was partially rescued by DQ. Moreover, DQ treatment significantly improved the response to ovulation induction and fertility in POI mice by extending reproductive life. Thus, cellular senescence plays critical roles in Cy-induced POI, and targeting senescent cells with senolytics, such as DQ, might be a promising strategy to protect against Cy-induced ovarian damage.

Efficacy of therapeutic drug monitoring-based antibiotic regimen in critically ill patients: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The efficacy of therapeutic drug monitoring (TDM)-based antimicrobial dosing optimization strategies on pharmacokinetics/pharmacodynamics and specific drug properties for critically ill patients is unclear. Here, we conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the effectiveness of TDM-based regimen in these patients. METHODS: Articles from three databases were systematically retrieved to identify relevant randomized control studies. Version two of the Cochrane tool for assessing risk of bias in randomized trials was used to assess the risk of bias in studies included in the analysis, and quality assessment of evidence was graded using the Grading of Recommendations Assessment, Development, and Evaluation approach. Primary outcome was the 28-day mortality and secondary outcome were in-hospital mortality, clinical cure, length of stay in the intensive care unit (ICU) and target attainment at day 1 and 3. RESULTS: In total, 5 studies involving 1011 patients were included for meta-analysis of the primary outcome, of which no significant difference was observed between TDM-based regimen and control groups (risk ratio [RR] 0.94, 95% confidence interval [CI]: 0.77-1.14; I2 = 0%). In-hospital mortality (RR 0.96, 95% CI: 0.76-1.20), clinical cure (RR 1.23, 95% CI: 0.91-1.67), length of stay in the ICU (mean difference 0, 95% CI: - 2.18-2.19), and target attainment at day 1 (RR 1.14, 95% CI: 0.88-1.48) and day 3 (RR 1.35, 95% CI: 0.90-2.03) were not significantly different between the two groups, and all evidence for the secondary outcomes had a low or very low level of certainty because the included studies had serious risk of bias, variation of definition for outcomes, and small sample sizes. CONCLUSION: TDM-based regimens had no significant efficacy for clinical or pharmacological outcomes. Further studies with other achievable targets and well-defined outcomes are required. TRIAL REGISTRATION: Clinical trial registration; PROSPERO ( https://www.crd.york.ac.uk/prospero/ ), registry number: CRD 42022371959. Registered 24 November 2022.

Epidemiology of sepsis in a Japanese administrative database.

Sepsis is the leading cause of death worldwide. Considering regional variations in the characteristics of patients with sepsis, a better understanding of the epidemiology in Japan will lead to further development of strategies for the prevention and treatment of sepsis. To investigate the epidemiology of sepsis, we conducted a systematic literature review of PubMed between 2003 and January 2023. Among the 78 studies using a Japanese administrative database, we included 20 that defined patients with sepsis as those with an infection and organ dysfunction. The mortality rate in patients with sepsis has decreased since 2010, reaching 18% in 2017. However, the proportion of inpatients with sepsis is increasing. A study comparing short-course (≤7 days) and long-course (≥8 days) antibiotic administration showed lower 28-day mortality in the short-course group. Six studies on the treatment of patients with septic shock reported that low-dose corticosteroids or polymyxin B hemoperfusion reduced mortality, whereas intravenous immunoglobulins had no such effect. Four studies investigating the effects of treatment in patients with sepsis-associated disseminated intravascular coagulation demonstrated that antithrombin may reduce mortality, whereas recombinant human soluble thrombomodulin does not. A descriptive study of medical costs for patients with sepsis showed that the effective cost per survivor decreased over an 8-year period from 2010 to 2017. Sepsis has a significant impact on public health, and is attracting attention as an ongoing issue. Further research to determine more appropriate prevention methods and treatment for sepsis should be a matter of priority.

Epigenetic inheritance is unfaithful at intermediately methylated CpG sites.

DNA methylation at the CpG dinucleotide is considered a stable epigenetic mark due to its presumed long-term inheritance through clonal expansion. Here, we perform high-throughput bisulfite sequencing on clonally derived somatic cell lines to quantitatively measure methylation inheritance at the nucleotide level. We find that although DNA methylation is generally faithfully maintained at hypo- and hypermethylated sites, this is not the case at intermediately methylated CpGs. Low fidelity intermediate methylation is interspersed throughout the genome and within genes with no or low transcriptional activity, and is not coordinately maintained between neighbouring sites. We determine that the probabilistic changes that occur at intermediately methylated sites are likely due to DNMT1 rather than DNMT3A/3B activity. The observed lack of clonal inheritance at intermediately methylated sites challenges the current epigenetic inheritance model and has direct implications for both the functional relevance and general interpretability of DNA methylation as a stable epigenetic mark.

Colloidal Stability of Emulsifier-free Oil-in-Water Emulsions: Effect of Oil Properties.

This study aims to determine the factors affecting the colloidal stabilization of emulsifier-free (EF) oil-in-water (O/W) emulsions prepared by mixing oil and water with a high-powered bath-type ultrasonicator (HPBath-US; 28 kHz, 300 W) in the absence of emulsifiers such as surfactants. The interrelation between the colloidal stability, oil properties (oil density, interfacial tension between oil and water, solubility parameter of oil, and oil viscosity), and emulsion properties (diameter and zeta-potential of oil droplets) of such EF-O/W emulsions were examined for this purpose. The colloidal stability of EF-vegetable oil-in-water emulsions (EF-VEG/W) was significantly higher than that of EF-hydrocarbon oil-in-water emulsions (EF-HDC/W) and EF-fatty acid-in-water emulsions (EF-FA/W). This can be attributed to the larger density of vegetable oils (VEG) (approximately 0.9 g cm-3), the formation of smaller-sized oil droplets (diameter of approximately 0.2 µm) in the EF-VEG/W emulsions, and the lower solubility parameter of VEG (δ around 1). Furthermore, the formation of smaller-sized oil droplets in the EF-O/W emulsions correlated with the physical properties of the oil.

Roles of endoplasmic reticulum stress in the pathophysiology of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-age women, affecting up to 15% of women in this group, and the most common cause of anovulatory infertility. Although its etiology remains unclear, recent research has revealed the critical role of endoplasmic reticulum (ER) stress in the pathophysiology of PCOS. ER stress is defined as a condition in which unfolded or misfolded proteins accumulate in the ER because of an imbalance in the demand for protein folding and the protein-folding capacity of the ER. ER stress results in the activation of several signal transduction cascades, collectively termed the unfolded protein response (UPR), which regulates various cellular activities. In principle, the UPR restores homeostasis and keeps the cell alive. However, if the ER stress cannot be resolved, it induces programmed cell death. ER stress has recently been recognized to play diverse roles in both physiological and pathological conditions of the ovary. In this review, we summarize current knowledge of the roles of ER stress in the pathogenesis of PCOS. ER stress pathways are activated in the ovaries of both a mouse model of PCOS and in humans, and local hyperandrogenism in the follicular microenvironment associated with PCOS is responsible for activating these. The activation of ER stress contributes to the pathophysiology of PCOS through multiple effects in granulosa cells. Finally, we discuss the potential for ER stress to serve as a novel therapeutic target for PCOS.

CPEB1-dependent disruption of the mRNA translation program in oocytes during maternal aging.

The molecular causes of deteriorating oocyte quality during aging are poorly defined. Since oocyte developmental competence relies on post-transcriptional regulations, we tested whether defective mRNA translation contributes to this decline in quality. Disruption in ribosome loading on maternal transcripts is present in old oocytes. Using a candidate approach, we detect altered translation of 3'-UTR-reporters and altered poly(A) length of the endogenous mRNAs. mRNA polyadenylation depends on the cytoplasmic polyadenylation binding protein 1 (CPEB1). Cpeb1 mRNA translation and protein levels are decreased in old oocytes. This decrease causes de-repression of Ccnb1 translation in quiescent oocytes, premature CDK1 activation, and accelerated reentry into meiosis. De-repression of Ccnb1 is corrected by Cpeb1 mRNA injection in old oocytes. Oocyte-specific Cpeb1 haploinsufficiency in young oocytes recapitulates all the translation phenotypes of old oocytes. These findings demonstrate that a dysfunction in the oocyte translation program is associated with the decline in oocyte quality during aging.

Mortality analysis among sepsis patients in and out of intensive care units using the Japanese nationwide medical claims database: a study by the Japan Sepsis Alliance study group.

BACKGROUND: A substantial number of sepsis patients require specialized care, including multidisciplinary care, close monitoring, and artificial organ support in the intensive care unit (ICU). However, the efficacy of ICU management on clinical outcomes remains insufficiently researched. Therefore, we tested the hypothesis that ICU admission would increase the survival rate among sepsis patients. METHODS: We conducted a retrospective study using the nationwide medical claims database of sepsis patients in Japan from 2010 to 2017 with propensity score matching to adjust for baseline imbalances. Patients aged over 20 years, with a combined diagnosis of presumed serious infection and organ failure, were included in this study. The primary outcome studied was the in-hospital mortality among non-ICU and ICU patients. In addition to propensity score matching, we performed a multivariable logistic regression analysis for the primary outcome. As the treatment policy was not extracted from the database, we performed sensitivity analyses to determine mortality differences in adults (20 ≤ age ≤ 64), independent patients, patients without malignant tumors, based on the assumption that treatment intensity is likely to increase in those population. RESULTS: Among 1,167,901 sepsis patients (974,289 in non-ICU and 193,612 in ICU settings), the unadjusted in-hospital mortality was 22.5% among non-ICU patients and 26.2% among ICU patients (3.7% [95% CI 3.5-3.9]). After propensity score matching, the in-hospital mortality was 29.2% among non-ICU patients and 25.8% among ICU patients ([Formula: see text] 3.4% [95% CI [Formula: see text] 3.7 to [Formula: see text] 3.1]). In-hospital mortality with a multivariable regression analysis ([Formula: see text] 5.0% [95% CI [Formula: see text] 5.2 to [Formula: see text] 4.8]) was comparable with the results of the propensity score matching analysis. In the sensitivity analyses, the mortality differences between non-ICU and ICU in adults, independent patients, and patients without malignant tumors were [Formula: see text] 2.7% [95% CI [Formula: see text] 3.3 to [Formula: see text] 2.2], [Formula: see text] 5.8% [95% CI [Formula: see text] 6.4 to [Formula: see text] 5.2], and [Formula: see text] 1.3% [95% CI [Formula: see text] 1.7 to [Formula: see text] 1.0], respectively. CONCLUSIONS: Herein, using the nationwide medical claims database, we demonstrated that ICU admission was potentially associated with decreasing in-hospital mortality among sepsis patients. Further investigations are warranted to validate these results and elucidate the mechanisms favoring ICU management on clinical outcomes.

Development of a Sensitive Anti-Human CCR9 Monoclonal Antibody (C9Mab-11) by N-Terminal Peptide Immunization.

The C-C chemokine receptor 9 (CCR9) belongs to the G-protein-coupled receptor superfamily, and is highly expressed on the T cells and intestinal cells. CCR9 regulates various immune responses by binding to the C-C chemokine ligand, CCL25, and is involved in inflammatory diseases and tumors. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CCR9 is necessary for treatment and diagnosis. In this study, we established a specific anti-human CCR9 (hCCR9) mAb; C9Mab-11 (mouse IgG2a, kappa), using the synthetic peptide immunization method. C9Mab-11 reacted with hCCR9-overexpressed Chinese hamster ovary-K1 (CHO/hCCR9) and hCCR9-endogenously expressed MOLT-4 (human T-lymphoblastic leukemia) cells in flow cytometry. The dissociation constant (KD) of C9Mab-11 for CHO/hCCR9 and MOLT-4 cells were determined to be 1.2 × 10-9 M and 4.9 × 10-10 M, respectively, indicating that C9Mab-11 possesses a high affinity for both exogenously and endogenously hCCR9-expressing cells. Furthermore, C9Mab-11 clearly detected hCCR9 protein in CHO/hCCR9 cells using western blot analysis. In summary, C9Mab-11 can be a useful tool for analyzing hCCR9-related biological responses.

Epitope Mapping of an Anti-Mouse CXCR6 Monoclonal Antibody (Cx6Mab-1) Using the 2 × Alanine Scanning Method.

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, cytotoxic T lymphocytes (CTLs), and natural killer cells. CXCR6 plays critical roles in local expansion of effector-like CTLs in tumor microenvironment to potentiate the antitumor response. Therefore, the development of anti-CXCR6 monoclonal antibodies (mAbs) is essential to evaluate the immune microenvironment of tumors. Using N-terminal peptide immunization, we previously developed an anti-mouse CXCR6 (mCXCR6) mAb, Cx6Mab-1 (rat IgG1, kappa) , which is useful for flow cytometry and western blotting. In this study, we determined the critical epitope of Cx6Mab-1 by enzyme-linked immunosorbent assay (ELISA) using the 1 × alanine scanning (1 × Ala-scan) method or the 2 × alanine scanning (2 × Ala-scan) method. Although we first performed ELISA by 1 × Ala-scan using one alanine-substituted peptides of mCXCR6 N-terminal domain (amino acids 1-20), we could not identify the Cx6Mab-1 epitope. We next performed ELISA by 2 × Ala-scan using two alanine (or glycine) residues-substituted peptides of mCXCR6 N-terminal domain, and found that Cx6Mab-1 did not recognize S8A-A9G, A9G-L10A, L10A-Y11A, and G13A-H14A of the mCXCR6 N-terminal peptide. The results indicate that the binding epitope of Cx6Mab-1 includes Ser8, Ala9, Leu10, Tyr11, Gly13, and His14 of mCXCR6. Therefore, we could demonstrate that the 2 × Ala scan method is useful for determining the critical epitope of mAbs.