Catalog No.	PA007126
Product Name	Mouse IgG1 Isotype Control Antibody (Clone: 12B9) | PA007126
Supplier Name	Syd Labs, Inc.
Brand Name	Syd Labs
Synonyms	Recombinant Mouse IgG1 Isotype Control, Mouse IgG1 Negative Control Antibody, mIgG1 Isotype Control
Summary	The in vivo grade recombinant mouse IgG1 isotype control antibody (mIgG1 isotype control) was produced in CHO cells.
Isotype	mouse IgG1, kappa
Applications	an isotype-matched negative control for mouse IgG1 antibody used in ELISA, Western Blot (WB), Flow Cytometry (Flow), Immunoprecipitation (IP), Immunohistochemistry
Immunogen	N/A.
Form Of Antibody	0.2 μM filtered solution of 1x PBS.
Endotoxin	Less than 1 EU/mg of protein as determined by LAL method.
Purity	>95% by SDS-PAGE under reducing conditions.
Shipping	The recombinant mouse IgG1 isotype control and mutants are shipped with ice pack. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage	Use a manual defrost freezer and avoid repeated freeze-thaw cycles. 1 month from date of receipt, 2 to 8°C as supplied. 3 months from date of receipt, -20°C to -70°C as supplied.
Order Offline	Phone: 1-617-401-8149 Fax: 1-617-606-5022 Email: message@sydlabs.com Or leave a message with a formal purchase order (PO) Or credit card.

Description

PA007126: Recombinant Mouse IgG1 Isotype Control Antibody(Clone: 12B9), In Vivo Grade

The Mouse IgG1 Isotype Control Antibody (12B9) is a must-have for researchers seeking to ensure experimental accuracy in immunological studies. Designed as a negative control, it distinguishes specific antibody binding from non-specific background signals in critical applications like Flow Cytometry, ELISA, Immunohistochemistry (IHC-P, IHC-F), and Western Blot. Available from trusted suppliers like us, this recombinant antibody matches Mouse IgG1 kappa primary antibodies and shows no reactivity to mouse, human, or rat proteins, making it ideal for validating experiments with human PBMCs or mouse splenocytes. With high purity (>95% by SDS-PAGE) and low endotoxin levels (<0.1 EU/µg), it delivers reliable results in both in vivo and in vitro research, encouraging researchers to trust its performance in sensitive assays.

Researchers value tools that streamline workflows and ensure reproducibility, and this antibody excels with its recombinant production in mammalian cells (CHO or HEK293), offering unmatched lot-to-lot consistency compared to hybridoma-derived alternatives. Available in versatile formats—purified, FITC, PE, APC conjugates, and Fc-silenced variants—it supports diverse needs, from flow cytometry isotype control for precise staining to IHC for tissue analysis. Supplied as a 0.2 µm filtered PBS solution (pH 7.2) or lyophilized with stabilizers, it is easy to use and stable, with storage at 2-8°C for short-term or -20°C for long-term, avoiding freeze-thaw cycles. Its ethical production, free from mouse ascites, aligns with modern research standards, making it a compelling choice for labs prioritizing quality and sustainability.

To drive purchasing decisions, the Mouse IgG1 Isotype Control (Clone: 12B9) is rigorously tested for minimal background staining across human and mouse tissues, backed by a 100% satisfaction guarantee and detailed technical data sheets from suppliers like us. Competitively priced (starting at >$36 for 1 mg) and available in flexible sizes (50 µg, 100 µg, 1 mg), it fits various research budgets. Fast shipping and responsive customer support ensure seamless integration into experiments, while its proven performance in applications like flow cytometry and IHC makes it a go-to for researchers seeking reliable results.

Please contact us to ask for a quote for the Fc silenced mouse IgG1 isotype control mutants, mIgG1 isotype control and mutants with Avi-, His-, and Flag-tags, and biotinylated mIgG1 isotype control and mutants. A variety of conjugates (such as dyes and fluorophores) with the mouse IgG1 isotype control and Fc-slient mutants are available.

References for Recombinant Mouse IgG1 Isotype Control (12B9):

1、Development of an inactivated vaccine candidate for SARS-CoV-2
Qiang Gao,et al.Science. 2020.PMCID: 32376603
“The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in an unprecedented public health crisis. Because of the novelty of the virus, there are currently no SARS-CoV-2-specific treatments or vaccines available. Therefore, rapid development of effective vaccines against SARS-CoV-2 are urgently needed. Here, we developed a pilot-scale production of PiCoVacc, a purified inactivated SARS-CoV-2 virus vaccine candidate, which induced SARS-CoV-2-specific neutralizing antibodies in mice, rats, and nonhuman primates. These antibodies neutralized 10 representative SARS-CoV-2 strains, suggesting a possible broader neutralizing ability against other strains. Three immunizations using two different doses, 3 or 6 micrograms per dose, provided partial or complete protection in macaques against SARS-CoV-2 challenge, respectively, without observable antibody-dependent enhancement of infection. These data support the clinical development and testing of PiCoVacc for use in humans.”

2、Antibody effector functions are associated with protection from respiratory syncytial virus
Yannic C Bartsch,et al.Cell. 2022.PMCID: 36513064
“Respiratory syncytial virus (RSV) infection is a major cause of severe lower respiratory tract infection and death in young infants and the elderly. With no effective prophylactic treatment available, current vaccine candidates aim to elicit neutralizing antibodies. However, binding and neutralization have poorly predicted protection in the past, and accumulating data across epidemiologic cohorts and animal models collectively point to a role for additional antibody Fc-effector functions. To begin to define the humoral correlates of immunity against RSV, here we profiled an adenovirus 26 RSV-preF vaccine-induced humoral immune response in a group of healthy adults that were ultimately challenged with RSV. Protection from infection was linked to opsonophagocytic functions, driven by IgA and differentially glycosylated RSV-specific IgG profiles, marking a functional humoral immune signature of protection against RSV. Furthermore, Fc-modified monoclonal antibodies able to selectively recruit effector functions demonstrated significant antiviral control in a murine model of RSV.
Keywords: Ad26; Fc effector functions; Fc glycosylation; IgA; RSV; antibodies; human challenge study; mAbs; vaccination.”

3、Mouse IgG2a Isotype Therapeutic Antibodies Elicit Superior Tumor Growth Control Compared with mIgG1 or mIgE
Natasa Vukovic,et al.Cancer Res Commun. 2023.PMCID: 36968226
“In the last decades, antibody-based tumor therapy has fundamentally improved the efficacy of treatment for patients with cancer. Currently, almost all tumor antigen-targeting antibodies approved for clinical application are of IgG1 Fc isotype. Similarly, the mouse homolog mIgG2a is the most commonly used in tumor mouse models. However, in mice, the efficacy of antibody-based tumor therapy is largely restricted to a prophylactic application. Direct isotype comparison studies in mice in a therapeutic setting are scarce. In this study, we assessed the efficacy of mouse tumor-targeting antibodies of different isotypes in a therapeutic setting using a highly systematic approach. To this end, we engineered and expressed antibodies of the same specificity but different isotypes, targeting the artificial tumor antigen CD90.1/Thy1.1 expressed by B16 melanoma cells. Our experiments revealed that in a therapeutic setting mIgG2a was superior to both mIgE and mIgG1 in controlling tumor growth. Furthermore, the observed mIgG2a antitumor effect was entirely Fc mediated as the protection was lost when an Fc-silenced mIgG2a isotype (LALA-PG mutations) was used. These data confirm mIgG2a superiority in a therapeutic tumor model.
Significance: Direct comparisons of different antibody isotypes of the same specificity in cancer settings are still scarce. Here, it is shown that mIgG2a has a greater effect compared with mIgG1 and mIgE in controlling tumor growth in a therapeutic setting.”

4、Influenza Infection in Humans Induces Broadly Cross-Reactive and Protective Neuraminidase-Reactive Antibodies
Yao-Qing Chen,et al.Cell. 2018.PMCID: 29625056
“Antibodies to the hemagglutinin (HA) and neuraminidase (NA) glycoproteins are the major mediators of protection against influenza virus infection. Here, we report that current influenza vaccines poorly display key NA epitopes and rarely induce NA-reactive B cells. Conversely, influenza virus infection induces NA-reactive B cells at a frequency that approaches (H1N1) or exceeds (H3N2) that of HA-reactive B cells. NA-reactive antibodies display broad binding activity spanning the entire history of influenza A virus circulation in humans, including the original pandemic strains of both H1N1 and H3N2 subtypes. The antibodies robustly inhibit the enzymatic activity of NA, including oseltamivir-resistant variants, and provide robust prophylactic protection, including against avian H5N1 viruses, in vivo. When used therapeutically, NA-reactive antibodies protected mice from lethal influenza virus challenge even 48 hr post infection. These findings strongly suggest that influenza vaccines should be optimized to improve targeting of NA for durable and broad protection against divergent influenza strains.
Keywords: B cell; human immunology; humoral immune response; influenza; monoclonal antibody; neuraminidase; therapeutics; vaccine; virus infection.”

5、Intranasal vaccination with lipid-conjugated immunogens promotes antigen transmucosal uptake to drive mucosal and systemic immunity
Brittany L Hartwell,et al.Sci Transl Med. 2022.PMCID: 35857825
“To combat the HIV epidemic and emerging threats such as SARS-CoV-2, immunization strategies are needed that elicit protection at mucosal portals of pathogen entry. Immunization directly through airway surfaces is effective in driving mucosal immunity, but poor vaccine uptake across the mucus and epithelial lining is a limitation. The major blood protein albumin is constitutively transcytosed bidirectionally across the airway epithelium through interactions with neonatal Fc receptors (FcRn). Exploiting this biology, here, we demonstrate a strategy of “albumin hitchhiking” to promote mucosal immunity using an intranasal vaccine consisting of protein immunogens modified with an amphiphilic albumin-binding polymer-lipid tail, forming amph-proteins. Amph-proteins persisted in the nasal mucosa of mice and nonhuman primates and exhibited increased uptake into the tissue in an FcRn-dependent manner, leading to enhanced germinal center responses in nasal-associated lymphoid tissue. Intranasal immunization with amph-conjugated HIV Env gp120 or SARS-CoV-2 receptor binding domain (RBD) proteins elicited 100- to 1000-fold higher antigen-specific IgG and IgA titers in the serum, upper and lower respiratory mucosa, and distal genitourinary mucosae of mice compared to unmodified protein. Amph-RBD immunization induced high titers of SARS-CoV-2-neutralizing antibodies in serum, nasal washes, and bronchoalveolar lavage. Furthermore, intranasal amph-protein immunization in rhesus macaques elicited 10-fold higher antigen-specific IgG and IgA responses in the serum and nasal mucosa compared to unmodified protein, supporting the translational potential of this approach. These results suggest that using amph-protein vaccines to deliver antigen across mucosal epithelia is a promising strategy to promote mucosal immunity against HIV, SARS-CoV-2, and other infectious diseases.”

6、Pre-clinical characterisation of E2814, a high-affinity antibody targeting the microtubule-binding repeat domain of tau for passive immunotherapy in Alzheimer’s disease
Malcolm Roberts,et al.Acta Neuropathol Commun. 2020.PMCID: 32019610
“Tau deposition in the brain is a pathological hallmark of many neurodegenerative disorders, including Alzheimer’s disease (AD). During the course of these tauopathies, tau spreads throughout the brain via synaptically-connected pathways. Such propagation of pathology is thought to be mediated by tau species (“seeds”) containing the microtubule binding region (MTBR) composed of either three repeat (3R) or four repeat (4R) isoforms. The tau MTBR also forms the core of the neuropathological filaments identified in AD brain and other tauopathies. Multiple approaches are being taken to limit tau pathology, including immunotherapy with anti-tau antibodies. Given its key structural role within fibrils, specifically targetting the MTBR with a therapeutic antibody to inhibit tau seeding and aggregation may be a promising strategy to provide disease-modifying treatment for AD and other tauopathies. Therefore, a monoclonal antibody generating campaign was initiated with focus on the MTBR. Herein we describe the pre-clinical generation and characterisation of E2814, a humanised, high affinity, IgG1 antibody recognising the tau MTBR. E2814 and its murine precursor, 7G6, as revealed by epitope mapping, are antibodies bi-epitopic for 4R and mono-epitopic for 3R tau isoforms because they bind to sequence motif HVPGG. Functionally, both antibodies inhibited tau aggregation in vitro. They also immunodepleted a variety of MTBR-containing tau protein species. In an in vivo model of tau seeding and transmission, attenuation of deposition of sarkosyl-insoluble tau in brain could also be observed in response to antibody treatment. In AD brain, E2814 bound different types of tau filaments as shown by immunogold labelling and recognised pathological tau structures by immunohistochemical staining. Tau fragments containing HVPGG epitopes were also found to be elevated in AD brain compared to PSP or control. Taken together, the data reported here have led to E2814 being proposed for clinical development.
Keywords: Alzheimer; Tau; immunotherapy; neurodegeneration; tauopathy.”

7、Nasal vaccination of triple-RBD scaffold protein with flagellin elicits long-term protection against SARS-CoV-2 variants including JN.1
Xian Li,et al.Signal Transduct Target Ther. 2024.PMCID: 38678055
“Developing a mucosal vaccine against SARS-CoV-2 is critical for combatting the epidemic. Here, we investigated long-term immune responses and protection against SARS-CoV-2 for the intranasal vaccination of a triple receptor-binding domain (RBD) scaffold protein (3R-NC) adjuvanted with a flagellin protein (KFD) (3R-NC + KFDi.n). In mice, the vaccination elicited RBD-specific broad-neutralizing antibody responses in both serum and mucosal sites sustained at high level over a year. This long-lasting humoral immunity was correlated with the presence of long-lived RBD-specific IgG- and IgA-producing plasma cells, alongside the Th17 and Tfh17-biased T-cell responses driven by the KFD adjuvant. Based upon these preclinical findings, an open labeled clinical trial was conducted in individuals who had been primed with the inactivated SARS-CoV-2 (IAV) vaccine. With a favorable safety profile, the 3R-NC + KFDi.n boost elicited enduring broad-neutralizing IgG in plasma and IgA in salivary secretions. To meet the challenge of frequently emerged variants, we further designed an updated triple-RBD scaffold protein with mutated RBD combinations, which can induce adaptable antibody responses to neutralize the newly emerging variants, including JN.1. Our findings highlight the potential of the KFD-adjuvanted triple-RBD scaffold protein is a promising prototype for the development of a mucosal vaccine against SARS-CoV-2 infection.”

8、A spike-based mRNA vaccine that induces durable and broad protection against porcine deltacoronavirus in piglets
Jizong Li,et al.J Virol. 2024.PMCID: 39158273
“Coronaviruses (CoVs) are important pathogens for humans and other vertebrates, causing severe respiratory and intestinal infections that have become a threat to public health because of the potential for interspecies transmission between animals and humans. Therefore, the development of safe, effective vaccines remains a top priority for the control of CoV infection. The unique immunological characteristics of vaccines featuring messenger RNA (mRNA) present an advantageous tool for coronavirus vaccine development. Here, we designed two lipid nanoparticle (LNP)-encapsulated mRNA (mRNA-LNP) vaccines: one encoding full-length spike (S) protein and the other encoding the spike ectodomain (Se) from porcine deltacoronavirus (PDCoV). Fourteen days after primary immunization, both mRNA vaccines induced high levels of immunoglobulin G and neutralizing antibodies in mice, with the S vaccine showing better performance than the Se vaccine. Passive immune protection of the S mRNA vaccine in suckling piglets was confirmed by the induction of robust PDCoV-specific humoral and cellular immune responses. The S mRNA vaccine also showed better protective effects than the inactivated vaccine. Our results suggest that the novel PDCoV-S mRNA-LNP vaccine may have the potential to combat PDCoV infection.
Importance: As an emerging porcine enteropathogenic coronavirus, porcine deltacoronavirus (PDCoV) has the potential for cross-species transmission, attracting extensive attention. Messenger RNA (mRNA) vaccines are a promising option for combating emerging and re-emerging infectious diseases, as evidenced by the demonstrated efficacy of the COVID-19 mRNA vaccine. Here, we first demonstrated that PDCoV-S mRNA-lipid nanoparticle (LNP) vaccines could induce potent humoral and cellular immune responses in mice. An evaluation of passive immune protection of S mRNA vaccines in suckling piglets confirmed that the protective effect of mRNA vaccine was better than that of inactivated vaccine. This study suggests that the PDCoV-S mRNA-LNP vaccine may serve as a potential and novel vaccine candidate for combating PDCoV infection.
Keywords: PDCoV; lipid nanoparticle; mRNA vaccine; spike protein; suckling piglets.”

9、Modeling MOG Antibody-Associated Disorder and Neuromyelitis Optica Spectrum Disorder in Animal Models: Visual System Manifestations
Jana Remlinger,et al.Neurol Neuroimmunol Neuroinflamm. 2023.PMCID: 37429715
“Background and objectives: Mechanisms of visual impairment in aquaporin 4 antibody (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-associated disorder (MOGAD) are incompletely understood. The respective impact of optic nerve demyelination and primary and secondary retinal neurodegeneration are yet to be investigated in animal models.
Methods: Active MOG35-55 experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6Jrj mice, and monoclonal MOG-IgG (8-18C5, murine), recombinant AQP4-IgG (rAb-53, human), or isotype-matched control IgG (Iso-IgG, human) was administered 10 days postimmunization. Mobility impairment was scored daily. Visual acuity by optomotor reflex and ganglion cell complex thickness (GCC, 3 innermost retinal layers) by optical coherence tomography (OCT) were longitudinally assessed. Histopathology of optic nerve and retina was investigated during presymptomatic, acute, and chronic disease phases for immune cells, demyelination, complement deposition, natural killer (NK) cell, AQP4, and astrocyte involvement, retinal ganglion cells (RGCs), and Müller cell activation. Groups were compared by nonparametric tests with a p value <0.05 indicating statistical significance.
Results: Visual acuity decreased from baseline to chronic phase in MOG-IgG (mean ± standard error of the mean: 0.54 ± 0.01 to 0.46 ± 0.02 cycles/degree, p < 0.05) and AQP4-IgG EAE (0.54 ± 0.01 to 0.43 ± 0.02, cycles/degree, p < 0.05). Immune cell infiltration of optic nerves started in presymptomatic AQP4-IgG, but not in MOG-IgG EAE (5.85 ± 2.26 vs 0.13 ± 0.10 macrophages/region of interest [ROI] and 1.88 ± 0.63 vs 0.15 ± 0.06 T cells/ROI, both p < 0.05). Few NK cells, no complement deposition, and stable glial fibrillary acid protein and AQP4 fluorescence intensity characterized all EAE optic nerves. Lower GCC thickness (Spearman correlation coefficient r = -0.44, p < 0.05) and RGC counts (r = -0.47, p < 0.05) correlated with higher mobility impairment. RGCs decreased from presymptomatic to chronic disease phase in MOG-IgG (1,705 ± 51 vs 1,412 ± 45, p < 0.05) and AQP4-IgG EAE (1,758 ± 14 vs 1,526 ± 48, p < 0.01). Müller cell activation was not observed in either model.
Discussion: In a multimodal longitudinal characterization of visual outcome in animal models of MOGAD and NMOSD, differential retinal injury and optic nerve involvement were not conclusively clarified. Yet optic nerve inflammation was earlier in AQP4-IgG-associated pathophysiology. Retinal atrophy determined by GCC thickness (OCT) and RGC counts correlating with mobility impairment in the chronic phase of MOG-IgG and AQP4-IgG EAE may serve as a generalizable marker of neurodegeneration.”

10、hUC-MSC transplantation therapy effects on lupus-prone MRL/lpr mice at early disease stages
Fengbiao Guo,et al.Stem Cell Res Ther. 2023.PMCID: 37605271
“Background: The efficacy of human umbilical cord mesenchymal stem cell (hUC-MSC) transplantation in treating systemic lupus erythematosus (SLE) has been confirmed by small-scale clinical trials. However, these trials focused on severe or refractory SLE, while few studies focused on mild SLE. Therefore, this study focused on the therapeutic effects of hUC-MSC transplantation in early-stage or mild MRL/lpr lupus model mice.
Methods: Commercially available hUC-MSCs were transplanted into 8-week-old MRL/lpr mice by tail vein injection. Flow cytometry was used to analyze B cells and their subsets in the peripheral blood. Further, plasma inflammatory factors, autoantibodies, and plasma biochemical indices were detected using protein chip technology and ELISA kits. In addition, pathological staining and immunofluorescence were performed to detect kidney injury in mice.
Results: hUC-MSC transplantation did not affect the mice’s body weight, and both middle and high dose hUC-MSC transplantation (MD and HD group) actually reduced spleen weight. hUC-MSC transplantation significantly decreased the proportion of plasmablasts (PB), IgG1- PB, IgG1+ PB, IgG1+ memory B (MB) cells, IgG1+ DN MB, and IgG1+ SP MB cells. The hUC-MSC transplantation had significantly reduced plasma levels of inflammatory factors, such as TNF-α, IFN-γ, IL-6, and IL-13. Pathological staining showed that the infiltration of glomerular inflammatory cells was significantly reduced and that the level of glomerular fibrosis was significantly alleviated in hUC-MSC-transplanted mice. Immunofluorescence assays showed that the deposition of IgG and IgM antibodies in the kidneys of hUC-MSC-transplanted mice was significantly lower than in the control.

Conclusion: hUC-MSC transplantation could inhibit the proliferation and differentiation of peripheral blood B cells in the early-stage of MRL/lpr mice, thereby alleviating the plasma inflammatory environment in mice, leading to kidney injury remission. The study provides a new and feasible strategy for SLE treatment.
Keywords: B cells; Immunosuppressive; Lupus mice; SLE; hUC-MSCs.”

11、An FcRn-targeted mucosal vaccine against SARS-CoV-2 infection and transmission
Weizhong Li,et al.Nat Commun. 2023.PMCID: 37932271
“SARS-CoV-2 is primarily transmitted through droplets and airborne aerosols, and in order to prevent infection and reduce viral spread vaccines should elicit protective immunity in the airways. The neonatal Fc receptor (FcRn) transfers IgG across epithelial barriers and can enhance mucosal delivery of antigens. Here we explore FcRn-mediated respiratory delivery of SARS-CoV-2 spike (S). A monomeric IgG Fc was fused to a stabilized spike; the resulting S-Fc bound to S-specific antibodies and FcRn. Intranasal immunization of mice with S-Fc and CpG significantly induced antibody responses compared to the vaccination with S alone or PBS. Furthermore, we intranasally immunized mice or hamsters with S-Fc. A significant reduction of virus replication in nasal turbinate, lung, and brain was observed following nasal challenges with SARS-CoV-2 and its variants. Intranasal immunization also significantly reduced viral airborne transmission in hamsters. Nasal IgA, neutralizing antibodies, lung-resident memory T cells, and bone-marrow S-specific plasma cells mediated protection. Hence, FcRn delivers an S-Fc antigen effectively into the airway and induces protection against SARS-CoV-2 infection and transmission.”

12、In vivo mRNA expression of a multi-mechanistic mAb combination protects against Staphylococcus aureus infection
Christine Tkaczyk,et al.Mol Ther. 2024.PMCID: 38822525
“Single monoclonal antibodies (mAbs) can be expressed in vivo through gene delivery of their mRNA formulated with lipid nanoparticles (LNPs). However, delivery of a mAb combination could be challenging due to the risk of heavy and light variable chain mispairing. We evaluated the pharmacokinetics of a three mAb combination against Staphylococcus aureus first in single chain variable fragment scFv-Fc and then in immunoglobulin G 1 (IgG1) format in mice. Intravenous delivery of each mRNA/LNP or the trio (1 mg/kg each) induced functional antibody expression after 24 h (10-100 μg/mL) with 64%-78% cognate-chain paired IgG expression after 3 days, and an absence of non-cognate chain pairing for scFv-Fc. We did not observe reduced neutralizing activity for each mAb compared with the level of expression of chain-paired mAbs. Delivery of the trio mRNA protected mice in an S. aureus-induced dermonecrosis model. Intravenous administration of the three mRNA in non-human primates achieved peak serum IgG levels ranging between 2.9 and 13.7 μg/mL with a half-life of 11.8-15.4 days. These results suggest nucleic acid delivery of mAb combinations holds promise and may be a viable option to streamline the development of therapeutic antibodies.
Keywords: Staphylococcus aureus; alpha toxin; bacteria pathogenesis; clumping factor A; immunotherapy; in vivo expressed monoclonal antibodies; mRNA/LNP; monoclonal antibody combination; mouse disease models; scFv-Fc.”

13、Identification of SKOR2 IgG as a novel biomarker of paraneoplastic neurologic syndrome
Mohamed Rezk,et al.Front Immunol. 2023.PMCID: 37795104
“Introduction: The development of new autoantigen discovery techniques, like programmable phage immunoprecipitation sequencing (PhIP-Seq), has accelerated the discovery of neural-specific autoantibodies. Herein, we report the identification of a novel biomarker for paraneoplastic neurologic syndrome (PNS), Sloan-Kettering-Virus-Family-Transcriptional-Corepressor-2 (SKOR2)-IgG, utilizing PhIP-Seq. We have also performed a thorough clinical validation using normal, healthy, and disease/cancer control samples.
Methods: Stored samples with unclassified staining at the junction of the Purkinje cell and the granule cell layers were analyzed by PhIP-Seq for putative autoantigen identification. The autoantigen was confirmed by recombinant antigen-expressing cell-based assay (CBA), Western blotting, and tissue immunofluorescence assay colocalization.
Results: PhIP-Seq data revealed SKOR2 as the candidate autoantigen. The target antigen was confirmed by a recombinant SKOR-2-expressing, and cell lysate Western blot. Furthermore, IgG from both patient samples colocalized with a commercial SKOR2-specific IgG on cryosections of the mouse brain. Both SKOR2 IgG-positive patients had central nervous system involvement, one presenting with encephalitis and seizures (Patient 1) and the other with cognitive dysfunction, spastic ataxia, dysarthria, dysphagia, and pseudobulbar affect (Patient 2). They had a refractory progressive course and were diagnosed with adenocarcinoma (Patient 1: lung, Patient 2: gallbladder). Sera from adenocarcinoma patients without PNS (n=30) tested for SKOR2-IgG were negative.
Discussion: SKOR2 IgG represents a novel biomarker for PNS associated with adenocarcinoma. Identification of additional SKOR2 IgG-positive cases will help categorize the associated neurological phenotype and the risk of underlying malignancy.
Keywords: antibody biomarker; gall bladder adenocarcinoma; lung adecarcinoma; paraneoplastic encephalitis; paraneoplastic neurologic syndrome.”

14、Epitope convergence of broadly HIV-1 neutralizing IgA and IgG antibody lineages in a viremic controller
Valérie Lorin,et al.J Exp Med. 2022.PMCID: 35230385
“Decrypting the B cell ontogeny of HIV-1 broadly neutralizing antibodies (bNAbs) is paramount for vaccine design. Here, we characterized IgA and IgG bNAbs of three distinct B cell lineages in a viremic controller, two of which comprised only IgG+ or IgA+ blood memory B cells; the third combined both IgG and IgA clonal variants. 7-269 bNAb in the IgA-only lineage displayed the highest neutralizing capacity despite limited somatic mutation, and delayed viral rebound in humanized mice. bNAbs in all three lineages targeted the N332 glycan supersite. The 2.8-Å resolution cryo-EM structure of 7-269-BG505 SOSIP.664 complex showed a similar pose as 2G12, on an epitope mainly composed of sugar residues comprising the N332 and N295 glycans. Binding and cryo-EM structural analyses showed that antibodies from the two other lineages interact mostly with glycans N332 and N386. Hence, multiple B cell lineages of IgG and IgA bNAbs focused on a unique HIV-1 site of vulnerability can codevelop in HIV-1 viremic controllers.”

15、Hybrid immunity to SARS-CoV-2 arises from serological recall of IgG antibodies distinctly imprinted by infection or vaccination
William N Voss,et al.Cell Rep Med. 2024.PMCID: 39094579
“We describe the molecular-level composition of polyclonal immunoglobulin G (IgG) anti-spike antibodies from ancestral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, vaccination, or their combination (“hybrid immunity”) at monoclonal resolution. Infection primarily triggers S2/N-terminal domain (NTD)-reactive antibodies, whereas vaccination mainly induces anti-receptor-binding domain (RBD) antibodies. This imprint persists after secondary exposures wherein >60% of ensuing hybrid immunity derives from the original IgG pool. Monoclonal constituents of the original IgG pool can increase breadth, affinity, and prevalence upon secondary exposures, as exemplified by the plasma antibody SC27. Following a breakthrough infection, vaccine-induced SC27 gained neutralization breadth and potency against SARS-CoV-2 variants and zoonotic viruses (half-maximal inhibitory concentration [IC50] ∼0.1-1.75 nM) and increased its binding affinity to the protective RBD class 1/4 epitope (dissociation constant [KD] < 5 pM). According to polyclonal escape analysis, SC27-like binding patterns are common in SARS-CoV-2 hybrid immunity. Our findings provide a detailed molecular definition of immunological imprinting and show that vaccination can produce class 1/4 (SC27-like) IgG antibodies circulating in the blood.
Keywords: COVID-19; Ig-seq; SARS-CoV-2; antibody feedback; bNAb; broadly neutralizing monoclonal antibody; cryo-EM; hybrid immunity; immunological imprinting; plasma.”

16、Epigallocatechin-3-Gallate as a Novel Vaccine Adjuvant
Yucheol Cheong,et al.Front Immunol. 2021.PMCID: 34868027
“Vaccine adjuvants from natural resources have been utilized for enhancing vaccine efficacy against infectious diseases. This study examined the potential use of catechins, polyphenolic materials derived from green tea, as adjuvants for subunit and inactivated vaccines. Previously, catechins have been documented to have irreversible virucidal function, with the possible applicability in the inactivated viral vaccine platform. In a mouse model, the coadministration of epigallocatechin-3-gallate (EGCG) with influenza hemagglutinin (HA) antigens induced high levels of neutralizing antibodies, comparable to that induced by alum, providing complete protection against the lethal challenge. Adjuvant effects were observed for all types of HA antigens, including recombinant full-length HA and HA1 globular domain, and egg-derived inactivated split influenza vaccines. The combination of alum and EGCG further increased neutralizing (NT) antibody titers with the corresponding hemagglutination inhibition (HI) titers, demonstrating a dose-sparing effect. Remarkably, EGCG induced immunoglobulin isotype switching from IgG1 to IgG2a (approximately >64-700 fold increase), exerting a more balanced TH1/TH2 response compared to alum. The upregulation of IgG2a correlated with significant enhancement of antibody-dependent cellular cytotoxicity (ADCC) function (approximately 14 fold increase), providing a potent effector-mediated protection in addition to NT and HI. As the first report on a novel class of vaccine adjuvants with built-in virucidal activities, the results of this study will help improve the efficacy and safety of vaccines for pandemic preparedness.
Keywords: ADCC; EGCG; IgG isotype switching; adjuvant; influenza.”

17、PD-L1 Antibody Pharmacokinetics and Tumor Targeting in Mouse Models for Infectious Diseases
Gerwin G W Sandker,et al.Front Immunol. 2022.PMCID: 35359962
“Background: Programmed death-ligand 1 (PD-L1) regulates immune homeostasis by promoting T-cell exhaustion. It is involved in chronic infections and tumor progression. Nuclear imaging using radiolabeled anti-PD-L1 antibodies can monitor PD-L1 tissue expression and antibody distribution. However, physiological PD-L1 can cause rapid antibody clearance from blood at imaging doses. Therefore, we hypothesized that inflammatory responses, which can induce PD-L1 expression, affect anti-PD-L1 antibody distribution. Here, we investigated the effects of three different infectious stimuli on the pharmacokinetics and tumor targeting of radiolabeled anti-PD-L1 antibodies in tumor-bearing mice.
Materials/methods: Anti-mouse-PD-L1 and isotype control antibodies were labelled with indium-111 ([111In]In-DTPA-anti-mPD-L1 and [111In]In-DTPA-IgG2a, respectively). We evaluated the effect of inflammatory responses on the pharmacokinetics of [111In]In-DTPA-anti-mPD-L1 in RenCa tumor-bearing BALB/c mice in three conditions: lipopolysaccharide (LPS), local Staphylococcus aureus, and heat-killed Candida albicans. After intravenous injection of 30 or 100 µg of [111In]In-DTPA-anti-mPD-L1 or [111In]In-DTPA-IgG2a, blood samples were collected 1, 4, and 24 h p.i. followed by microSPECT/CT and ex vivo biodistribution analyses. PD-L1 expression, neutrophil, and macrophage infiltration in relevant tissues were evaluated immunohistochemically.
Results: In 30 µg of [111In]In-DTPA-anti-mPD-L1 injected tumor-bearing mice the LPS-challenge significantly increased lymphoid organ uptake compared with vehicle controls (spleen: 49.9 ± 4.4%ID/g versus 21.2 ± 6.9%ID/g, p < 0.001), resulting in lower blood levels (3.6 ± 1.6%ID/g versus 11.5 ± 7.2%ID/g; p < 0.01) and reduced tumor targeting (8.1 ± 4.5%ID/g versus 25.2 ± 5.2%ID/g, p < 0.001). Local S. aureus infections showed high PD-L1+ neutrophil influx resulting in significantly increased [111In]In-DTPA-anti-mPD-L1 uptake in affected muscles (8.6 ± 2.6%ID/g versus 1.7 ± 0.8%ID/g, p < 0.001). Heat-killed Candida albicans (Hk-C. albicans) challenge did not affect pharmacokinetics. Increasing [111In]In-DTPA-anti-mPD-L1 dose to 100 µg normalized blood clearance and tumor uptake in LPS-challenged mice, although lymphoid organ uptake remained higher. Infectious stimuli did not affect [111In]In-DTPA-IgG2a pharmacokinetics.
Conclusions: This study shows that anti-PD-L1 antibody pharmacokinetics and tumor targeting can be significantly altered by severe inflammatory responses, which can be compensated for by increasing the tracer dose. This has implications for developing clinical PD-L1 imaging protocols in onco-immunology. We further demonstrate that radiolabeled anti-PD-L1 antibodies can be used to evaluate PD-L1 expression changes in a range of infectious diseases. This supports the exploration of using these techniques to assess hosts’ responses to infectious stimuli.
Keywords: Candida albicans; PD-L1; Staphylococcus aureus; antibody; cancer; infectious diseases; lipopolysaccharide; nuclear imaging (SPECT).”

18、Isotype-specific plasma cells express divergent transcriptional programs
Brett W Higgins,et al.Proc Natl Acad Sci U S A. 2022.PMCID: 35704755
“Antibodies are produced across multiple isotypes with distinct properties that coordinate initial antigen clearance and confer long-term antigen-specific immune protection. Here, we interrogate the molecular programs of isotype-specific murine plasma cells (PC) following helper T cell-dependent immunization and within established steady-state immunity. We developed a single-cell-indexed and targeted molecular strategy to dissect conserved and divergent components of the rapid effector phase of antigen-specific IgM+ versus inflammation-modulating programs dictated by type 1 IgG2a/b+ PC differentiation. During antibody affinity maturation, the germinal center (GC) cycle imparts separable programs for post-GC type 2 inhibitory IgG1+ and type 1 inflammatory IgG2a/b+ PC to direct long-term cellular function. In the steady state, two subsets of IgM+ and separate IgG2b+ PC programs clearly segregate from splenic type 3 IgA+ PC programs that emphasize mucosal barrier protection. These diverse isotype-specific molecular pathways of PC differentiation control complementary modules of antigen clearance and immune protection that could be selectively targeted for immunotherapeutic applications and vaccine design.
Keywords: antibodies; isotype; plasma cell; single-cell RNA-seq.”

19、A novel mouse strain optimized for chronic human antibody administration
Aaron Gupta,et al.Proc Natl Acad Sci U S A. 2022.PMCID: 35235456
“Therapeutic human IgG antibodies are routinely tested in mouse models of oncologic, infectious, and autoimmune diseases. However, assessing the efficacy and safety of long-term administration of these agents has been limited by endogenous anti-human IgG immune responses that act to clear human IgG from serum and relevant tissues, thereby reducing their efficacy and contributing to immune complex–mediated pathologies, confounding evaluation of potential toxicity. For this reason, human antibody treatment in mice is generally limited in duration and dosing, thus failing to recapitulate the potential clinical applications of these therapeutics. Here, we report the development of a mouse model that is tolerant of chronic human antibody administration. This model combines both a human IgG1 heavy chain knock-in and a full recapitulation of human Fc receptor (FcγR) expression, providing a unique platform for in vivo testing of human monoclonal antibodies with relevant receptors beyond the short term. Compared to controls, hIgG1 knock-in mice mount minimal anti-human IgG responses, allowing for the persistence of therapeutically active circulating human IgG even in the late stages of treatment in chronic models of immune thrombocytopenic purpura and metastatic melanoma.
Keywords: Fc receptors; humanized mouse; immunoglobulin; tolerance.”

20、COL6A6 Peptide Vaccine Alleviates Atherosclerosis through Inducing Immune Response and Regulating Lipid Metabolism in Apoe-/- Mice
Dongmei Tang,et al.Cells. 2024.PMCID: 39329770
“Atherosclerosis is an autoimmune disease characterized by lipid imbalances and chronic inflammation within blood vessels, with limited preventive and treatment options currently available. In this study, a vaccine prepared with COL6A6 peptide (named the Pep_A6 vaccine) was administered to immunize Apoe-/- mice, and the immune mechanism of the Pep_A6 vaccine against atherosclerosis was first investigated. The results of arterial oil red O staining demonstrated that the Pep_A6 vaccine significantly reduced the atherosclerotic plaque area in Apoe-/- mice fed with a high-fat diet for 20 weeks. A flow cytometry analysis revealed that the Pep_A6 vaccine inhibited Th1 cell differentiation and increased the proportion of Treg cells. Furthermore, there was a significant increase in Ly6Clow monocytes observed in the vaccinated group. The ELISA results showed that the Pep_A6 vaccine induced a significant expression of Pep_A6-specific antibody IgG and IgG1 in mouse serum. Additionally, we found that the Pep_A6 vaccine significantly decreased serum LDL-C content and regulated the expression of genes related to liver lipid metabolism. Together, our findings suggest that the Pep_A6 vaccine alleviates atherosclerosis by inducing a positive immune response and regulating lipid metabolism, providing new insights into potential prevention strategies for atherosclerosis as an innovative vaccine.
Keywords: Pep_A6 vaccine; Th/Treg cell; antigen-specific antibody; atherosclerosis; lipid metabolism.”

Other in vivo grade Recombinant IgG Isotype Control Antibodies and Mutants:
Recombinant Human IgG1 Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Human IgG2 Isotype Control Antibody, In vivo Grade
Recombinant Human IgG3 Isotype Control Antibody, In vivo Grade
Recombinant Human IgG4-S228P Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Mouse IgG1 Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Mouse IgG2a Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Mouse IgG2b Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Mouse IgG2c Isotype Control Antibody and Mutants, In vivo Grade
Recombinant Mouse IgG3 Isotype Control Antibody, In vivo Grade
Recombinant Rat IgG1 Isotype Control Antibody, In vivo Grade
Recombinant Rat IgG2a Isotype Control Antibody, In vivo Grade
Recombinant Rat IgG2b Isotype Control Antibody, In vivo Grade
Recombinant Rat IgG2c Isotype Control Antibody, In vivo Grade
Recombinant Hamster IgG1 Isotype Control Antibody, In vivo Grade
Recombinant Hamster IgG2 Isotype Control Antibody, In vivo Grade

In vivo Grade Recombinant IgG Fc Proteins:
Recombinant Human IgG1 Fc Protein (hIgG1), In vivo Grade
Recombinant Human IgG2 Fc Protein (hIgG2), In vivo Grade
Recombinant Human IgG4 Fc Protein (hIgG4), In vivo Grade
Recombinant Mouse IgG1 Fc Protein (mIgG1), In vivo Grade
Recombinant Mouse IgG2a Fc Protein (mIgG2a), In vivo Grade
Recombinant Mouse IgG2b Fc Protein (mIgG2b), In vivo Grade
Recombinant Rat IgG2a Fc Protein (rtIgG2a), In vivo Grade
Recombinant Rat IgG2b Fc Protein (rtIgG2b), In vivo Grade
Recombinant Llama IgG2b Fc Protein (lIgG2b), In vivo Grade
Recombinant Rabbit IgG Fc Protein (rIgG), In vivo Grade

Fc ELISA Kits and Reagents:
Human Fc ELISA Kit
Mouse Fc ELISA Kit
Human Fc ELISA Reagent Kit
Mouse Fc ELISA Reagent Kit

Mouse IgG1 Isotype Control (12B9) from: In Vivo Grade Recombinant Mouse IgG1 Isotype Control Antibody PA007126: Syd Labs

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