De Novo Variants Found in Three Distinct Schizophrenia Populations Hit a Common Core Gene Network Related to Microtubule and Actin Cytoskeleton Gene Ontology Classes.

Schizophrenia (SZ) is a heterogeneous and debilitating psychiatric disorder with a strong genetic component. To elucidate functional networks perturbed in schizophrenia, we analysed a large dataset of whole-genome studies that identified SNVs, CNVs, and a multi-stage schizophrenia genome-wide association study. Our analysis identified three subclusters that are interrelated and with small overlaps: GO:0007017~Microtubule-Based Process, GO:00015629~Actin Cytoskeleton, and GO:0007268~SynapticTransmission. We next analysed three distinct trio cohorts of 75 SZ Algerian, 45 SZ French, and 61 SZ Japanese patients. We performed Illumina HiSeq whole-exome sequencing and identified de novo mutations using a Bayesian approach. We validated 88 de novo mutations by Sanger sequencing: 35 in French, 21 in Algerian, and 32 in Japanese SZ patients. These 88 de novo mutations exhibited an enrichment in genes encoding proteins related to GO:0051015~actin filament binding (p = 0.0011) using David, and enrichments in GO: 0003774~transport (p = 0.019) and GO:0003729~mRNA binding (p = 0.010) using Amigo. One of these de novo variant was found in CORO1C coding sequence. We studied Coro1c haploinsufficiency in a Coro1c+/- mouse and found defects in the corpus callosum. These results could motivate future studies of the mechanisms surrounding genes encoding proteins involved in transport and the cytoskeleton, with the goal of developing therapeutic intervention strategies for a subset of SZ cases.

SPTLC2 variants are associated with early-onset ALS and FTD due to aberrant sphingolipid synthesis.

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a devastating, incurable neurodegenerative disease. A subset of ALS patients manifests with early-onset and complex clinical phenotypes. We aimed to elucidate the genetic basis of these cases to enhance our understanding of disease etiology and facilitate the development of targeted therapies. METHODS: Our research commenced with an in-depth genetic and biochemical investigation of two specific families, each with a member diagnosed with early-onset ALS (onset age of <40 years). This involved whole-exome sequencing, trio analysis, protein structure analysis, and sphingolipid measurements. Subsequently, we expanded our analysis to 62 probands with early-onset ALS and further included 440 patients with adult-onset ALS and 1163 healthy controls to assess the prevalence of identified genetic variants. RESULTS: We identified heterozygous variants in the serine palmitoyltransferase long chain base subunit 2 (SPTLC2) gene in patients with early-onset ALS. These variants, located in a region closely adjacent to ORMDL3, bear similarities to SPTLC1 variants previously implicated in early-onset ALS. Patients with ALS carrying these SPTLC2 variants displayed elevated plasma ceramide levels, indicative of increased serine palmitoyltransferase (SPT) activity leading to sphingolipid overproduction. INTERPRETATION: Our study revealed novel SPTLC2 variants in patients with early-onset ALS exhibiting frontotemporal dementia. The combination of genetic evidence and the observed elevation in plasma ceramide levels establishes a crucial link between dysregulated sphingolipid metabolism and ALS pathogenesis. These findings expand our understanding of ALS's genetic diversity and highlight the distinct roles of gene defects within SPT subunits in its development.

Hydrogen sulfide and polysulfides induce GABA/glutamate/D-serine release, facilitate hippocampal LTP, and regulate behavioral hyperactivity.

Hydrogen sulfide (H2S) and polysulfides (H2Sn, n ≥ 2) are signaling molecules produced by 3-mercaptopyruvate sulfurtransferase (3MST) that play various physiological roles, including the induction of hippocampal long-term potentiation (LTP), a synaptic model of memory formation, by enhancing N-methyl-D-aspartate (NMDA) receptor activity. However, the presynaptic action of H2S/H2Sn on neurotransmitter release, regulation of LTP induction, and animal behavior are poorly understood. Here, we showed that H2S/H2S2 applied to the rat hippocampus by in vivo microdialysis induces the release of GABA, glutamate, and D-serine, a co-agonist of NMDA receptors. Animals with genetically knocked-out 3MST and the target of H2S2, transient receptor potential ankyrin 1 (TRPA1) channels, revealed that H2S/H2S2, 3MST, and TRPA1 activation play a critical role in LTP induction, and the lack of 3MST causes behavioral hypersensitivity to NMDA receptor antagonism, as in schizophrenia. H2S/H2Sn, 3MST, and TRPA1 channels have therapeutic potential for psychiatric diseases and cognitive deficits.

Impairment of serine transport across the blood-brain barrier by deletion of Slc38a5 causes developmental delay and motor dysfunction.

Brain L-serine is critical for neurodevelopment and is thought to be synthesized solely from glucose. In contrast, we found that the influx of L-serine across the blood-brain barrier (BBB) is essential for brain development. We identified the endothelial Slc38a5, previously thought to be a glutamine transporter, as an L-serine transporter expressed at the BBB in early postnatal life. Young Slc38a5 knockout (KO) mice exhibit developmental alterations and a decrease in brain L-serine and D-serine, without changes in serum or liver amino acids. Slc38a5-KO brains exhibit accumulation of neurotoxic deoxysphingolipids, synaptic and mitochondrial abnormalities, and decreased neurogenesis at the dentate gyrus. Slc38a5-KO pups exhibit motor impairments that are affected by the administration of L-serine at concentrations that replenish the serine pool in the brain. Our results highlight a critical role of Slc38a5 in supplying L-serine via the BBB for proper brain development.

MAST4 promotes primary ciliary resorption through phosphorylation of Tctex-1.

The primary cilium undergoes cell cycle-dependent assembly and disassembly. Dysregulated ciliary dynamics are associated with several pathological conditions called ciliopathies. Previous studies showed that the localization of phosphorylated Tctex-1 at Thr94 (T94) at the ciliary base critically regulates ciliary resorption by accelerating actin remodeling and ciliary pocket membrane endocytosis. Here, we show that microtubule-associated serine/threonine kinase family member 4 (MAST4) is localized at the primary cilium. Suppressing MAST4 blocks serum-induced ciliary resorption, and overexpressing MAST4 accelerates ciliary resorption. Tctex-1 binds to the kinase domain of MAST4, in which the R503 and D504 residues are key to MAST4-mediated ciliary resorption. The ciliary resorption and the ciliary base localization of phospho-(T94)Tctex-1 are blocked by the knockdown of MAST4 or the expression of the catalytic-inactive site-directed MAST4 mutants. Moreover, MAST4 is required for Cdc42 activation and Rab5-mediated periciliary membrane endocytosis during ciliary resorption. These results support that MAST4 is a novel kinase that regulates ciliary resorption by modulating the ciliary base localization of phospho-(T94)Tctex-1. MAST4 is a potential new target for treating ciliopathies causally by ciliary resorption defects.

Epitope Mapping of the Novel Anti-Human CCR9 Monoclonal Antibody (C9Mab-11) by 2 × Alanine Scanning.

We recently developed a novel anti-human C-C chemokine receptor 9 (hCCR9) monoclonal antibody (mAb), C9Mab-11, which is applicable to flow cytometry, western blotting, and enzyme-linked immunosorbent assay (ELISA). This study aims to identify the binding epitope of C9Mab-11 by using 1 × and 2 × alanine (or glycine) substituted-hCCR9 peptides (1 × and 2 × Ala-scan) by ELISA. According to the 1 × Ala-scan analysis, the response of C9Mab-11 was diminished against M13A of the hCCR9 peptide, but was not eliminated. In the 2 × Ala-scan analysis, the reactions were abolished in the substitution of P11A-N12A, N12A-M13A, and M13A-A14G of hCCR9 N-terminal peptides. The results indicate that the binding epitope of C9Mab-11 includes Pro11, Asn12, Met13, and Ala14 of hCCR9, with the region around Met13 being particularly important. The successful identification of the C9Mab-11 epitope might be useful for the future pathophysiological analysis of hCCR9.

Epitope Mapping of Anti-Mouse CCR3 Monoclonal Antibodies (C3Mab-6 and C3Mab-7).

One of G protein-coupled receptors, CC chemokine receptor 3 (CCR3), is expressed in eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 levels in the serum of colorectal cancer patients are significantly higher than in control groups. Moreover, CCR3 is essential for recruiting eosinophils into the lung. Therefore, CCR3 is considered both a therapeutic target for colorectal cancer and allergic diseases. Previously, we established anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C3Mab-6 (rat IgG1, kappa) and C3Mab-7 (rat IgG1, kappa), by immunizing a rat with an N-terminal peptide of mCCR3. These mAbs can be used in flow cytometry and enzyme-linked immunosorbent assays. In this study, we performed the epitope mapping of C3Mab-6 and C3Mab-7 using alanine scanning. The reactivity between these mAbs and point mutants of mCCR3 were analyzed using flow cytometry. The results indicated that Phe3, Asn4, Thr5, Asp6, Glu7, Lys9, Thr10, and Glu13 of mCCR3 are essential for C3Mab-6 binding, whereas Phe15 and Glu16 are essential for C3Mab-7 binding.

Epitope Mapping of an Anti-EpCAM Monoclonal Antibody (EpMab-37) Using the Alanine Scanning Method.

The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein, and plays critical roles in cell adhesion, proliferation, and tumorigenesis. EpCAM has been considered as a promising target for tumor diagnosis and therapy. Anti-EpCAM monoclonal antibodies (mAbs) have been developed for EpCAM-overexpressed tumors, and several clinical trials have demonstrated promising outcomes. We previously established an anti-EpCAM mAb, EpMab-37 (mouse IgG1, kappa), using the Cell-Based Immunization and Screening method. EpMab-37 was revealed to recognize the conformational epitope of EpCAM. In this study, we determined the critical epitope of EpMab-37 by flow cytometry using the 1 × alanine scanning (1 × Ala-scan) and the 2 × alanine scanning (2 × Ala-scan) method. We first performed flow cytometry by 1 × Ala-scan using one alanine (or glycine)-substituted EpCAM mutants, which were expressed on Chinese hamster ovary-K1 cells, and found that the EpMab-37 did not recognize the R163A mutant of EpCAM. We next performed flow cytometry by 2 × Ala-scan using two alanine (or glycine) residues-substituted EpCAM mutants, and confirmed that EpMab-37 did not recognize R163A-including mutants of EpCAM. The results indicated that the critical binding epitope of EpMab-37 includes Arg163 of EpCAM.

Antitumor activities of a defucosylated anti­EpCAM monoclonal antibody in colorectal carcinoma xenograft models.

Epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein, which is highly expressed on tumor cells. As EpCAM plays a crucial role in cell adhesion, survival, proliferation, stemness, and tumorigenesis, it has been considered as a promising target for tumor diagnosis and therapy. Anti­EpCAM monoclonal antibodies (mAbs) have been developed and have previously demonstrated promising outcomes in several clinical trials. An anti­EpCAM mAb, EpMab­37 (mouse IgG1, kappa) was previously developed by the authors, using the cell­based immunization and screening method. In the present study, a defucosylated version of anti­EpCAM mAb (EpMab­37­mG2a­f) was generated to evaluate the antitumor activity against EpCAM­positive cells. EpMab­37­mG2a­f recognized EpCAM­overexpressing CHO­K1 (CHO/EpCAM) cells with a moderate binding­affinity [dissociation constant (KD)=2.2x10­8 M] using flow cytometry. EpMab­37­mG2a­f exhibited potent antibody­dependent cellular cytotoxicity (ADCC) and complement­dependent cytotoxicity (CDC) for CHO/EpCAM cells by murine splenocytes and complements, respectively. Furthermore, the administration of EpMab­37­mG2a­f significantly suppressed CHO/EpCAM xenograft tumor development compared with the control mouse IgG. EpMab­37­mG2a­f also exhibited a moderate binding­affinity (KD=1.5x10­8 M) and high ADCC and CDC activities for a colorectal cancer cell line (Caco­2 cells). The administration of EpMab­37­mG2a­f to Caco­2 tumor­bearing mice significantly suppressed tumor development compared with the control. By contrast, EpMab­37­mG2a­f never suppressed the xenograft tumor growth of Caco­2 cells in which EpCAM was knocked out. On the whole, these results indicate that EpMab­37­mG2a­f may exert antitumor activities against EpCAM­positive cancers and may thus be a promising therapeutic regimen for colorectal cancer.

Establishment of a Sensitive Monoclonal Antibody Against Mouse CCR9 (C9Mab-24) for Flow Cytometry.

The CC chemokine receptor 9 (CCR9), also known as CD199, is one of chemokine receptors. The CC chemokine ligand 25 (CCL25) is known to be the only ligand for CCR9. The CCR9-CCL25 interaction plays important roles in chemotaxis of lymphocytes and tumor cell migration. Therefore, CCR9-CCL25 axis is a promising target for tumor therapy and diagnosis. In this study, we established a sensitive and specific monoclonal antibody (mAb) against mouse CCR9 (mCCR9) using N-terminal peptide immunization method. The established anti-mCCR9 mAb, C9Mab-24 (rat immunoglobulin [IgG]2a, kappa), reacted with mCCR9-overexpressed Chinese hamster ovary-K1 (CHO/mCCR9) and mCCR9-endogenously expressed cell line, RL2, through flow cytometry. Kinetic analyses using flow cytometry showed that the dissociation constants (KD) of C9Mab-24 for CHO/mCCR9 and RL2 cell lines were 6.0 × 10-9 M and 4.7 × 10-10 M, respectively. Results indicated that C9Mab-24 is useful for detecting mCCR9 through flow cytometry, thereby providing a possibility for targeting mCCR9-expressing cells in vivo experiments.

Defucosylated Mouse-Dog Chimeric Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody (H77Bf) Exerts Antitumor Activities in Mouse Xenograft Models of Canine Osteosarcoma.

Human epidermal growth factor receptor 2 (HER2) has been studied in many human cancer types, and its overexpression and/or gene mutation contribute to the poor prognosis. Therefore, HER2 is an important therapeutic target in various cancer types, including breast and gastric cancers. We previously developed an anti-HER2 monoclonal antibody (mAb), H2Mab-77 (mouse IgG1, kappa), which detects HER2 and dog HER2 (dHER2) with high sensitivity and specificity. In this study, we produced a defucosylated mouse-dog chimeric anti-HER2 mAb (H77Bf), and investigated the reactivity against canine osteosarcoma D-17 cells by flow cytometry. Furthermore, we showed that H77Bf exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against D-17 cells in vitro and exhibited the potent antitumor activity in vivo. These results suggest that H77Bf exerts antitumor effects against dHER2-expressing canine tumors and could be valuable as part of an antibody treatment regimen for them.

Antitumor Activities in Mouse Xenograft Models of Canine Fibroblastic Tumor by Defucosylated Mouse-Dog Chimeric Anti-HER2 Monoclonal Antibody (H77Bf).

Human epidermal growth factor receptor 2 (HER2) is a cell surface type I transmembrane glycoprotein that is overexpressed on a variety of solid tumors and transduces the oncogenic signaling upon homo- and heterodimerization with HER families. Anti-HER2 monoclonal antibodies (mAbs) including trastuzumab and its antibody-drug conjugate have been shown to improve patients' survival in HER2-positive breast, gastric, and lung cancers. Canine tumors have advantages as naturally occurring tumor models, and share biological and histological characteristics with human tumors. In this study, we generated a defucosylated version of mouse-dog chimeric anti-HER2 mAb (H77Bf) derived from H2Mab-77 (mouse IgG1, kappa). H77Bf possesses the high binding affinity (a dissociation constant: 8.7 × 10-10 M) for a dog HER2 (dHER2)-expressing canine fibroblastic tumor cell line (A-72). H77Bf exhibited antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity for A-72 cells. Moreover, intraperitoneal administration of H77Bf significantly suppressed the development of A-72 tumor compared with the control dog IgG in a mouse xenograft model. These results indicate that H77Bf exerts antitumor activities against dHER2-expressing canine cancers, which could provide a valuable information for canine cancer treatment.

Epitope Mapping Using the Cell-Based 2 × Alanine Substitution Method About the Anti-mouse CXCR6 Monoclonal Antibody, Cx6Mab-1.

An anti-mouse CXC chemokine receptor 6 (mCXCR6) monoclonal antibody (mAb), Cx6Mab-1, was developed recently. Cx6Mab-1 is applicable for flow cytometry, Western blotting, and enzyme-linked immunosorbent assay. The purpose of this study is to determine the binding epitope of Cx6Mab-1 using 2 × alanine mutated mCXCR6. Analysis of flow cytometry revealed that Cx6Mab-1 did not recognize S8A-A9G, L10A-Y11A, D12A-G13A, and H14A-Y15A mutants of mCXCR6. The results clearly indicate that the binding epitope of Cx6Mab-1 includes Ser8, Ala9, Leu10, Tyr11, Asp12, Gly13, His14, and Tyr15 of mCXCR6. The successful determination of the Cx6Mab-1 epitope might contribute to the pathophysiological investigation of mCXCR6.

Epitope Mapping of Anti-Mouse CCR3 Monoclonal Antibodies Using Flow Cytometry.

The CC chemokine receptor 3 (CCR3) is a receptor for CC chemokines, including CCL5/RANTES, CCL7/MCP-3, and CCL11/eotaxin. CCR3 is expressed on the surface of eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 and its ligands are involved in airway hyperresponsiveness in allergic asthma, ocular allergies, and cancers. Therefore, CCR3 is an attractive target for those therapies. Previously, anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C3Mab-3 (rat IgG2a, kappa), and C3Mab-4 (rat IgG2a, kappa) were developed using the Cell-Based Immunization and Screening (CBIS) method. In this study, the binding epitope of these mAbs was investigated using flow cytometry. A CCR3 extracellular domain-substituted mutant analysis showed that C3Mab-3, C3Mab-4, and a commercially available mAb (J073E5) recognized the N-terminal region (amino acids 1-38) of mCCR3. Next, alanine scanning was conducted in the N-terminal region. The results revealed that the Ala2, Phe3, Asn4, and Thr5 of mCCR3 are involved in C3Mab-3 binding, whereas Ala2, Phe3, and Thr5 are essential to C3Mab-4 binding, and Ala2 and Phe3 are crucial to J073E5 binding. These results reveal the involvement of the N-terminus of mCCR3 in the recognition of C3Mab-3, C3Mab-4, and J073E5.

A Defucosylated Anti-EpCAM Monoclonal Antibody (EpMab-37-mG2a-f) Exerts Antitumor Activity in Xenograft Model.

The epithelial cell adhesion molecule (EpCAM) is a stem cell and carcinoma antigen, which mediates cellular adhesion and proliferative signaling by the proteolytic cleavage. In contrast to low expression in normal epithelium, EpCAM is frequently overexpressed in various carcinomas, which correlates with poor prognosis. Therefore, EpCAM has been considered as a promising target for tumor diagnosis and therapy. Using the Cell-Based Immunization and Screening (CBIS) method, we previously established an anti-EpCAM monoclonal antibody (EpMab-37; mouse IgG1, kappa). In this study, we investigated the antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and an antitumor activity by a defucosylated mouse IgG2a-type of EpMab-37 (EpMab-37-mG2a-f) against a breast cancer cell line (BT-474) and a pancreatic cancer cell line (Capan-2), both of which express EpCAM. EpMab-37-mG2a-f recognized BT-474 and Capan-2 cells with a moderate binding-affinity [apparent dissociation constant (KD): 2.9 × 10-8 M and 1.8 × 10-8 M, respectively] by flow cytometry. EpMab-37-mG2a-f exhibited ADCC and CDC for both cells by murine splenocytes and complements, respectively. Furthermore, administration of EpMab-37-mG2a-f significantly suppressed the xenograft tumor development compared with the control mouse IgG. These results indicated that EpMab-37-mG2a-f exerts antitumor activities and could provide valuable therapeutic regimen for breast and pancreatic cancers.

Antitumor Activity of an Anti-EGFR/HER2 Bispecific Antibody in a Mouse Xenograft Model of Canine Osteosarcoma.

The overexpression of epidermal growth factor receptors (EGFRs) has been reported in various human tumors, including breast, gastric, lung, colorectal, and pancreatic cancers. Humanized anti-EGFR and anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibodies (mAbs) have been shown to improve patients' survival. Canine tumors resemble human tumors in the initiation and progression. We previously established a defucosylated mouse-dog chimeric anti-EGFR mAb (E134Bf) and a mouse-dog chimeric anti-HER2 mAb (H77Bf), which exerted antitumor activities in canine tumor xenograft models. Here, we produced E134Bf antibody fused to H77Bf single chain Fv at the light chains (E134Bf-H77scFv). The bispecific E134Bf-H77scFv recognized dog EGFR (dEGFR) and dog HER2 (dHER2)-overexpressed Chinese hamster ovary-K1 cells by flow cytometry. E134Bf-H77scFv also reacted with dEGFR/dHER2-positive canine osteosarcoma D-17 cells, and possesses a high binding-affinity (KD: 1.3 × 10-9 M). Furthermore, E134Bf-H77scFv exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against D-17 cells in the presence of canine mononuclear cells and complement, respectively. Moreover, administration of E134Bf-H77scFv suppressed the development of D-17 xenograft tumor in mice early compared with the control dog IgG, E134Bf and H77Bf alone. These results indicate that E134Bf-H77scFv exerts antitumor activities against dEGFR/dHER2-positive canine tumors, and could be a valuable treatment regimen for canine tumors.

Epitope Mapping of an Anti-Mouse CCR2 Monoclonal Antibody (C2Mab-6) Using Enzyme-Linked Immunosorbent Assay.

CC chemokine receptor type-2 (CCR2) is a member of the G protein-coupled receptors, and is mainly expressed on cell surface of immune cells. CCR2 binds to its ligand, C-C motif chemokine 2 (also named as monocyte chemoattractant protein-1), which involves in the tumor progression by modulating the tumor microenvironment. Therefore, the monoclonal antibody (mAb) targeting CCR2 could be one of the strategies for cancer treatment. In this study, we investigated the critical epitope of C2Mab-6, an anti-mouse CCR2 (mCCR2) mAb developed by N-terminal peptides immunization. We first performed enzyme-linked immunosorbent assay (ELISA) using N-terminal peptides of mCCR2 and demonstrated that C2Mab-6 recognizes 1-19 amino acids of mCCR2. We further performed ELISA using 20 alanine-substituted peptides of mCCR2. C2Mab-6 lost the reaction to the alanine-substituted peptides of D3A, N4A, M6A, P8A, Q9A, and F10A. These results indicate that the binding epitope of C2Mab-6 includes Asp3, Asn4, Met6, Pro8, Gln9, and Phe10 of mCCR2.

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.

Development of a Novel Anti-Mouse CCR6 Monoclonal Antibody (C6Mab-13) by N-Terminal Peptide Immunization.

The CC chemokine receptor 6 (CCR6) is a G protein-coupled receptor family member that is highly expressed in B lymphocytes, certain subsets of effector and memory T cells, and immature dendritic cells. CCR6 has only one chemokine ligand, CCL20. The CCL20-CCR6 axis has been recognized as a therapeutic target for autoimmune diseases and tumor. This study developed specific monoclonal antibodies (mAbs) against mouse CCR6 (mCCR6) using the peptide immunization method. The established anti-mCCR6 mAb, C6Mab-13 (rat IgG1, kappa), reacted with mCCR6-overexpressed Chinese hamster ovary-K1 (CHO/mCCR6), and mCCR6-endogenously expressed P388 (mouse lymphoid neoplasma) and J774-1 (mouse macrophage-like) cells in flow cytometry. The dissociation constant (KD) of C6Mab-13 for CHO/mCCR6 cells was determined to be 2.8 × 10-9 M, indicating that C6Mab-13 binds to mCCR6 with high affinity. In summary, C6Mab-13 is useful for detecting mCCR6-expressing cells through flow cytometry.