scholarly journals 652 Anti-PD-L1/IL-15 KD033 activated macrophages and induced anti-tumor immunity in the tumor-microenvironment

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A681-A681
Author(s):  
Stella Martomo ◽  
George Wang ◽  
Zhanna Polonskaya ◽  
Xenia Luna ◽  
Dan Lu ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Transgenic Mice ◽  
Tumor Immunity ◽  
Immune Cells ◽  
Immune Gene ◽  
List Type ◽  
Double Positive ◽  
Double Positive Cell ◽  
Animal Care

BackgroundKD033 is a clinical-stage bispecific fusion molecule consisting of a high-affinity anti-human-PD-L1 antibody and human IL-15. Previous studies with KD033 in mice expressing functional human PD-1 and PD-L1 showed that KD033 was efficacious in reducing the growth of both PD-L1 positive and negative tumors.1 In the microenvironment of PD-L1 negative tumors, PD-L1 would still be expressed by some immune cells such as macrophages. The goal of the current study is to evaluate direct effect of KD033 on macrophages through in vitro studies and assess its contribution to anti-tumor immunity.MethodsMonocyte-derived human macrophages were treated with either KD033, the non-targeting IL15 fusion counterpart (ntKD033) or anti-PD-L1 antibody in vitro, and the supernatants were analyzed for cytokine/chemokine secretion. Human-PD-1/PD-L1 transgenic C57BL/6 mice subcutaneously transplanted with the human-PD-L1 positive or negative MC38 colon carcinoma were treated with KD033 intravenously when tumors reached 100 mm3. Tumor infiltrating cell populations were evaluated with Immunohistochemistry (IHC).ResultsIn vitro cultures with KD033 induced macrophages to secrete inflammatory cytokines such as IFNγ to a much higher level compared to ntKD033 cultures at the same concentrations. The anti-PD-L1 antibody alone did not induce macrophages to secrete IFNγ. IHC on KD033-treated human PD-1/PD-L1 transgenic mice showed that PD-L1 negative and positive MC38 tumors have similar levels of CD8 T cell tumor infiltrations. IHC with the macrophage marker CD68 showed higher level of CD68/IFNγ double positive cell infiltrations on PD-L1 negative tumors that was correlated with increased tumor growth inhibitions.ConclusionsIncreased in vitro IFNγ secretion from KD033-treated macrophages correlated with increased CD68/IFNγ double positive cell infiltrations in PD-L1 negative MC38 tumors from KD033-treated human PD-1/PD-L1 transgenic mice as evaluated by IHC. We hypothesized that our anti-PD-L1/IL15 KD033 induces anti-tumor immunity in PD-L1 negative tumors by activating PD-L1-expressing immune cells such as macrophages in the tumor microenvironment.Reference1. Martomo S, et al. Single-Dose anti–PD-L1/IL-15 fusion protein KD033 generates synergistic antitumor immunity with robust tumor-immune gene signatures and memory responses. Mol Cancer Ther 2021;20(2):347–356.Ethics ApprovalMouse studies were conducted for Kadmon by Wuxi AppTec Inc. All the procedures related to animal handling, care and the treatment in the study were performed according to the guidelines approved by the Institutional Animal Care and Use Committee (IACUC) of WuXi AppTec following the guidance of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).

scholarly journals Estrogen/ER in anti-tumor immunity regulation to tumor cell and tumor microenvironment

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tiecheng Wang ◽  
Jiakang Jin ◽  
Chao Qian ◽  
Jianan Lou ◽  
Jinti Lin ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Immunotherapy ◽  
Tumor Immunity ◽  
Immune Cells ◽  
Target Genes ◽  
Target Therapy ◽  
Treatment Strategies ◽  
Signal Transduction Pathway ◽  
Pathway Activation ◽  
Immune System Regulation

AbstractAs the essential sexual hormone, estrogen and its receptor has been proved to participate in the regulation of autoimmunity diseases and anti-tumor immunity. The adjustment of tumor immunity is related to the interaction between cancer cells, immune cells and tumor microenvironment, all of which is considered as the potential target in estrogen-induced immune system regulation. However, the specific mechanism of estrogen-induced immunity is poorly understood. Typically, estrogen causes the nuclear localization of estrogen/estrogen receptor complex and alternates the transcription pattern of target genes, leading to the reprogramming of tumor cells and differentiation of immune cells. However, the estrogen-induced non-canonical signal pathway activation is also crucial to the rapid function of estrogen, such as NF-κB, MAPK-ERK, and β-catenin pathway activation, which has not been totally illuminated. So, the investigation of estrogen modulatory mechanisms in these two manners is vital for the tumor immunity and can provide the potential for endocrine hormone targeted cancer immunotherapy. Here, this review summarized the estrogen-induced canonical and non-canonical signal transduction pathway and aimed to focus on the relationship among estrogen and cancer immunity as well as immune-related tumor microenvironment regulation. Results from these preclinical researches elucidated that the estrogen-target therapy has the application prospect of cancer immunotherapy, which requires the further translational research of these treatment strategies.

scholarly journals 695 Oral delivery of a microbial extracellular vesicle induces potent anti-tumor immunity in mice

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A737-A737
Author(s):  
Loise Francisco-Anderson ◽  
Loise Francisco-Anderson ◽  
Mary Abdou ◽  
Michael Goldberg ◽  
Erin Troy ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Extracellular Vesicles ◽  
Tumor Immunity ◽  
Extracellular Vesicle ◽  
The Body ◽  
Checkpoint Inhibition ◽  
Small Intestinal ◽  
The Impact

BackgroundThe small intestinal axis (SINTAX) is a network of anatomic and functional connections between the small intestine and the rest of the body. It acts as an immunosurveillance system, integrating signals from the environment that affect physiological processes throughout the body. The impact of events in the gut in the control of tumor immunity is beginning to be appreciated. We have previously shown that an orally delivered single strain of commensal bacteria induces anti-tumor immunity preclinically via pattern recognition receptor-mediated activation of innate and adaptive immunity. Some bacteria produce extracellular vesicles (EVs) that share molecular content with the parent bacterium in a particle that is roughly 1/1000th the volume in a non-replicating form. We report here an orally-delivered and gut-restricted bacterial EV which potently attenuates tumor growth to a greater extent than whole bacteria or checkpoint inhibition.MethodsEDP1908 is a preparation of extracellular vesicles produced by a gram-stain negative strain of bacterium of the Oscillospiraceae family isolated from a human donor. EDP1908 was selected for its immunostimulatory profile in a screen of EVs from a range of distinct microbial strains. Its mechanism of action was determined by ex vivo analysis of the tumor microenvironment (TME) and by in vitro functional studies with murine and human cells.ResultsOral treatment of tumor-bearing mice with EDP1908 shows superior control of tumor growth compared to checkpoint inhibition (anti-PD-1) or an intact microbe. EDP1908 significantly increased the percentage of IFNγ and TNF producing CD8+ CTLs, NK cells, NKT cells and CD4+ cells in the tumor microenvironment (TME). EDP1908 also increased tumor-infiltrating dendritic cells (DC1 and DC2). Analysis of cytokines in the TME showed significant increases in IP-10 and IFNg production in mice treated with EDP1908, creating an environment conducive to the recruitment and activation of anti-tumor lymphocytes.ConclusionsThis is the first report of striking anti-tumor effects of an orally delivered microbial extracellular vesicle. These data point to oral EVs as a new class of immunotherapeutic drugs. They are particularly effective at harnessing the biology of the small intestinal axis, acting locally on host cells in the gut to control distal immune responses within the TME. EDP1908 is in preclinical development for the treatment of cancer.Ethics ApprovalPreclinical murine studies were conducted under the approval of the Avastus Preclinical Services’ Ethics Board. Human in vitro samples were attained by approval of the IntegReview Ethics Board; informed consent was obtained from all subjects.

scholarly journals In Vitro Evaluation of CD276-CAR NK-92 Functionality, Migration and Invasion Potential in the Presence of Immune Inhibitory Factors of the Tumor Microenvironment

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1020
Author(s):  
Stefan Grote ◽  
Guillermo Ureña-Bailén ◽  
Kenneth Chun-Ho Chan ◽  
Caroline Baden ◽  
Markus Mezger ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Solid Tumors ◽  
Immune Cells ◽  
Immune Cell ◽  
Nk Cell ◽  
Migration And Invasion ◽  
Cellular Immunotherapy ◽  
Knock Out ◽  
Immunosuppressive Tumor Microenvironment

Background: Melanoma is the most lethal of all skin-related cancers with incidences continuously rising. Novel therapeutic approaches are urgently needed, especially for the treatment of metastasizing or therapy-resistant melanoma. CAR-modified immune cells have shown excellent results in treating hematological malignancies and might represent a new treatment strategy for refractory melanoma. However, solid tumors pose some obstacles for cellular immunotherapy, including the identification of tumor-specific target antigens, insufficient homing and infiltration of immune cells as well as immune cell dysfunction in the immunosuppressive tumor microenvironment (TME). Methods: In order to investigate whether CAR NK cell-based immunotherapy can overcome the obstacles posed by the TME in melanoma, we generated CAR NK-92 cells targeting CD276 (B7-H3) which is abundantly expressed in solid tumors, including melanoma, and tested their effectivity in vitro in the presence of low pH, hypoxia and other known factors of the TME influencing anti-tumor responses. Moreover, the CRISPR/Cas9-induced disruption of the inhibitory receptor NKG2A was assessed for its potential enhancement of NK-92-mediated anti-tumor activity. Results: CD276-CAR NK-92 cells induced specific cytolysis of melanoma cell lines while being able to overcome a variety of the immunosuppressive effects normally exerted by the TME. NKG2A knock-out did not further improve CAR NK-92 cell-mediated cytotoxicity. Conclusions: The strong cytotoxic effect of a CD276-specific CAR in combination with an “off-the-shelf” NK-92 cell line not being impaired by some of the most prominent negative factors of the TME make CD276-CAR NK-92 cells a promising cellular product for the treatment of melanoma and beyond.

scholarly journals In Vivo CRISPR Screens Identify E3 Ligase Cop1 as a Modulator of Macrophage Infiltration and Cancer Immunotherapy Target

2020 ◽  
Author(s):  
Xiaoqing Wang ◽  
Collin Tokheim ◽  
Binbin Wang ◽  
Shengqing Stan Gu ◽  
Qin Tang ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Cancer Immunotherapy ◽  
Tumor Immunity ◽  
Large Scale ◽  
Integrated Approach ◽  
Immune Checkpoint Blockade ◽  
Macrophage Infiltration ◽  
List Type

SUMMARYDespite remarkable clinical efficacies of immune checkpoint blockade (ICB) in cancer treatment, ICB benefits in triple-negative breast cancer (TNBC) remain limited. Through pooled in vivo CRISPR knockout (KO) screens in syngeneic TNBC mouse models, we found that inhibition of the E3 ubiquitin ligase Cop1 in cancer cells decreases the secretion of macrophage-associated chemokines, reduces tumor macrophage infiltration, and shows synergy in anti-tumor immunity with ICB. Transcriptomics, epigenomics, and proteomics analyses revealed Cop1 functions through proteasomal degradation of the C/ebpδ protein. Cop1 substrate Trib2 functions as a scaffold linking Cop1 and C/ebpδ, which leads to polyubiquitination of C/ebpδ. Cop1 inhibition stabilizes C/ebpδ to suppress the expression of macrophage chemoattractant genes. Our integrated approach implicates Cop1 as a target for improving cancer immunotherapy efficacy by regulating chemokine secretion and macrophage levels in the TNBC tumor microenvironment.HighlightsLarge-scale in vivo CRISPR screens identify new immune targets regulating the tumor microenvironmentCop1 knockout in cancer cells enhances anti-tumor immunityCop1 modulates chemokine secretion and macrophage infiltration into tumorsCop1 targets C/ebpδ degradation via Trib2 and influences ICB response

scholarly journals The Immune Endocannabinoid System of the Tumor Microenvironment

2020 ◽  
Vol 21 (23) ◽  
pp. 8929
Author(s):  
Melanie Kienzl ◽  
Julia Kargl ◽  
Rudolf Schicho
Keyword(s):  
Tumor Microenvironment ◽  
Tumor Progression ◽  
Immune Cells ◽  
Cannabinoid Receptors ◽  
Immune Cell ◽  
Tumor Development ◽  
Endocannabinoid System ◽  
Cell Functions ◽  
In Vitro Effects

Leukocytes are part of the tumor microenvironment (TME) and are critical determinants of tumor progression. Because of the immunoregulatory properties of cannabinoids, the endocannabinoid system (ECS) may have an important role in shaping the TME. Members of the ECS, an entity that consists of cannabinoid receptors, endocannabinoids and their synthesizing/degrading enzymes, have been associated with both tumor growth and rejection. Immune cells express cannabinoid receptors and produce endocannabinoids, thereby forming an “immune endocannabinoid system”. Although in vitro effects of exogenous cannabinoids on immune cells are well described, the role of the ECS in the TME, and hence in tumor development and immunotherapy, is still elusive. This review/opinion discusses the possibility that the “immune endocannabinoid system” can fundamentally influence tumor progression. The widespread influence of cannabinoids on immune cell functions makes the members of the ECS an interesting target that could support immunotherapy.

IL-6/STAT3 signaling impaired induction of cancer-antigen specific T cells via down-regulation of dendritic cells in tumor microenvironment.

2015 ◽  
Vol 33 (3_suppl) ◽  
pp. 590-590 ◽  
Author(s):  
Yosuke Ohno ◽  
Hidemitsu Kitamura ◽  
Junya Ohtake ◽  
Shun Kaneumi ◽  
Kentaro Sumida ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cell ◽  
Tumor Immunity ◽  
Immune Cells ◽  
Surface Expression ◽  
Colorectal Cancers ◽  
Expression Levels ◽  
Stat3 Signaling ◽  
Hla Dr

590 Background: Immunosuppression in tumor microenvironments is a critical issue for cancer immunotherapy. Recently, the effectiveness of immuno-check point therapy has been reported on various types of solid tumors. But, the effectiveness in colorectal cancer was poor compared to other cancers, such as melanoma and renal cell carcinoma. Correct regulation of dendritic cell (DC) function in tumors is important for inducing anti-tumor immunity. We have been demonstrated that IL-6 inhibits antigen presentation by DCs through STAT3 activation in tumor-bearing mice. In this study, we focused on the role of the IL-6/STAT3 signaling cascade in human DCs. Methods: Both IL-6 and pSTAT3 expressions in tumor sites of colorectal cancers was verified by immunohistostaining. CD11b+CD11c+DCs in cancer tissues and PBMCs were isolated by fluorescence-activated cell sorting system and investigated about the surface molecules such as HLA-DR, T cell stimulating ability, and effector gene expression levels. Moreover, we investigated influence of IL-6/STAT3 signaling in human DCs in vitro. Results: The results of IHC revealed that IL-6 was preferentially produced by cancer-associated fibroblasts and immune cells in the tissues of colorectal cancers. In addition, it was confirmed that STAT3 was activated in tumor-infiltrating immune cells. Tumor infiltrating CD11b+CD11c+ DCs highly induced IL-6 gene, down-regulated surface expression of HLA-DR, and attenuated T cell stimulating ability. In vitro experiments showed that IL-6-mediated STAT3 activation reduced surface expression of HLA-DR. COX2, cathepsin L (CTSL), and arginase activity were are involved in the IL-6-mediated down-regulation of surface expression levels of HLA-DR expression levels on DCs. Gene expressions of CTSL, ARG1 as well as IL6 in tumor infiltrating CD11b+CD11c+DCs were much higher than those of PBMCs. Conclusions: IL-6-mediated STAT3 activation inhibits functional maturation of DCs, causing suppression of anti-tumor immunity in colorectal cancer. Therefore, inhibition of the IL-6/STAT3 signaling pathway could be a promising strategy for improving immunotherapies for colorectal cancer patients.

scholarly journals Indoleamine 2,3-dioxygenase regulates anti-tumor immunity in lung cancer by metabolic reprogramming of immune cells in the tumor microenvironment

Oncotarget ◽  
2016 ◽  
Vol 7 (46) ◽  
pp. 75407-75424 ◽  
Author(s):  
Cara C. Schafer ◽  
Yong Wang ◽  
Kenneth P. Hough ◽  
Anandi Sawant ◽  
Stefan C. Grant ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Tumor Microenvironment ◽  
Tumor Immunity ◽  
Immune Cells ◽  
Metabolic Reprogramming ◽  
Indoleamine 2,3 Dioxygenase

scholarly journals 853 ACTM-838: a microbial-based immunotherapy that delivers combination IL-15 + engineered STING to tumor-resident APCs after IV dosing in T-cell excluded solid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A894-A894
Author(s):  
Haixing Kehoe ◽  
Alexandre Iannello ◽  
Keith Cheung ◽  
Bret Peterson ◽  
Marie Marotel ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Tumor Immunity ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Systemic Administration ◽  
Type I ◽  
Cell Recruitment ◽  
Metastatic Setting

BackgroundIn a metastatic setting, systemically-administered therapies that overcome the immunosuppressive tumor microenvironment to promote T-cell recruitment and T-cell cytolytic function will be required to elicit durable anti-tumor immunity. To accomplish this, the STACT (S. Typhimurium-Attenuated Cancer Therapy) platform was developed. STACT is a live bacterial product that has been highly modified using precision genome editing for the following properties: (1) enhanced tolerability after IV dosing, (2) tumor-specific enrichment, (3) phagocytosis by tumor-resident antigen-presenting cells (APCs) with a lack of epithelial cell infectivity, (4) multiplexed genetic cargo delivery, and (5) attenuation of bacterial pathways that impair CD8+ T-cell function. An extensive screening campaign was performed to identify ideal encoded immunomodulatory payload combinations delivered by STACT for efficacy against T-cell excluded tumors.MethodsChromosomal edits to the STACT platform strain were made using PCR. A panel of immunomodulatory proteins, including cytokines, type I interferon (IFN)-inducing factors, co-stimulatory receptors, checkpoint antibodies and TGFβR-Fc decoys were tested for combinatorial potency using STACT. An engineered STING (eSTING) was designed through an extensive protein engineering campaign to identify optimal variants. Combinations were evaluated in primary human APCs using in vitro functional assays, where STACT IL-15Rα-IL-15 (IL-15) + eSTING (ACTM-838) emerged as a lead candidate. ACTM-838 was then evaluated in multiple murine tumor models for therapeutic efficacy and mechanism, as well as tolerability in rodents and primates after systemic administration.ResultsCombinatorial target profiling led to the discovery of ACTM-838, a STACT encoding IL-15 + eSTING. In vitro, ACTM-838 payloads synergistically produced high levels of type I IFN and T-cell recruitment and activation factors from primary human APCs. In vivo, ACTM-838 demonstrated a high degree of complete tumor responses that were entirely CD8+ T-cell dependent. In an autochthonous breast cancer model that lacks any significant lymphocyte infiltrate, ACTM-838 was able to uniformly enrich in each spontaneous lesion to high levels after IV dosing and resulted in significant CD8+ T-cell infiltration. In primates, ACTM-838 was well-tolerated, rapidly cleared, and elicited minimal cytokine response after IV dosing.ConclusionsACTM-838 is a highly attenuated, precision genome-engineered bacterial immunotherapy that delivers IL-15 + eSTING to phagocytic APCs of the solid tumor microenvironment after systemic administration. In preclinical studies, ACTM-838 promotes CD8+ T-cell mediated tumor clearance in T-cell excluded tumors and elicits durable anti-tumor immunity, and is well tolerated in primates. Based on these data, ACTM-838 was nominated for clinical development and has entered cGMP manufacturing and IND-enabling studies.Ethics ApprovalAll animals were used according to protocols approved by an Institutional Animal Care and Use Committee and maintained in specific pathogen-free conditions in a barrier facility.

scholarly journals 884 Engineered toxin body mediated depletion of TIGIT expressing immune cells for cancer immunotherapy

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A926-A926
Author(s):  
Elizabeth Saputra ◽  
Garrett Cornelison ◽  
Jennifer Mitchell ◽  
Karia Williams ◽  
Andrea Mendiola ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Cells ◽  
Immune Cell ◽  
Single Agent ◽  
Antibody Fragment ◽  
Cell Surface Receptor ◽  
Mouse Tumor ◽  
List Type ◽  
Proof Of Concept

BackgroundTIGIT (T cell immunoreceptor with Ig and ITIM domains) is an exciting novel target for immuno-oncology which functions as an immune checkpoint on multiple immune cell types including memory CD8+, CD4+ Treg, and memory CD4+ cells. TIGIT upregulation on tumor infiltrating lymphocytes (TILs) has been observed in multiple cancer types and contributes to an immunosuppressive tumor microenvironment (TME). Interestingly, TIGIT is commonly co-expressed with PD-1 on Tregs in the TME, tumor antigen specific CD8+ T cells and CD8+ TILs, leading to weakened anti-tumor immune responses.1–2 To date, TIGIT inhibiting monoclonal antibodies (mAb) have shown little activity as a monotherapy in clinical and preclinical studies. 3–4 Therefore, current clinical trials are now focused on combining TIGIT mAbs with known commercial PD-1 or PD-L1 mAbs. A TIGIT-specific engineered toxin body (ETB) represents a wholly new approach to targeting TIGIT expressing cells including those co-expressing TIGIT and PD-1.MethodsETBs targeting TIGIT were designed to deplete TIGIT-expressing TILs, including Tregs, directly in the TME. ETBs are proteins that consist of an antibody fragment genetically fused to a proprietary de-immunized (DI) form of the Shiga-like toxin A subunit (SLTA). These proteins are specific for a cell surface receptor, and function through triggering rapid internalization upon binding, followed by an enzymatic and irreversible termination of ribosomal protein synthesis resulting in cellular apoptosis. Here we provide proof of concept for ETBs as a novel modality for the depletion of TIGIT-expressing immune cells.ResultsTIGIT-targeting ETBs exhibit potent in vitro cytotoxicity of TIGIT over-expressing cell lines (IC50<1nM). These ETBs also lead to apoptotic depletion of ex vivo TIGIT-expressing regulatory T cells (Tregs) from healthy donors. In mixed culture assays, TIGIT ETBs increase the proliferation of TIGIT negative T cells by depleting TIGIT-expressing T cells.ConclusionsStudies to assess pharmacodynamics and efficacy of TIGIT targeting ETBs using a double knock-in (TIGIT and PD-1) mouse tumor model are ongoing, but these early proof of concept in vitro data support the hypothesis that ETBs can deplete TIGIT positive immune cell populations including those co-expressing PD-1. It is possible that targeted TIGIT inhibition through ETB-induced cell death could tip the balance towards tumor regression by eliminating this novel checkpoint (and TIGIT/PD-1 co-expression) at the level of the TME.ReferencesJinhua X, Ji W, Shouliang C, Liangfeng Z. Expression of immune checkpoints in T cells of esophageal cancer patients. Oncotarget 2016;7(39):1–10.Blessin NC, Simon R, Kluth M, Fischer K, et al. Patterns of TIGIT expression in lymphatic tissue, inflammation and cancer. Dis Markers 2019;2019:1–13.Johnston RJ, Comps-Agrar L, Hackney J, Yu X, et al. The immunoreceptor TIGIT regulates anti-tumor and antiviral CD8(+) T effector function. Cancer Cell 2014;26(6):923–927.Bendell JC, Bedrad P, Bang Y-J, LoRusso P, et al. Phase Ia/Ib dose-escalation study of the anti-TIGIT antibody Tiragolumab as a single agent and in combination with atezolizumab in patients with advanced solid tumors. Proceedings: AACR Annual Meeting 2020; April 27–28, 2020 and June 22–24, 2020; Philadelphia, PA.

scholarly journals A potent bispecific nanobody protects hACE2 mice against SARS-CoV-2 infection via intranasal administration

2021 ◽  
Author(s):  
Xilin Wu ◽  
Lin Cheng ◽  
Ming Fu ◽  
Bilian Huang ◽  
Linjing Zhu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Intranasal Administration ◽  
List Type ◽  
Potential Candidate ◽  
Intranasal Delivery ◽  
Wild Type ◽  
Viral Inhibition ◽  
Live Virus

AbstractThe dramatically expanding COVID-19 needs multiple effective countermeasures. Neutralizing antibodies are a potential therapeutic strategy for treating COVID-19. A number of neutralizing nanobodies (Nbs) were reported for their in vitro activities. However, in vivo protection of these nanobodies was not reported in animal models. In the current report, we characterized several RBD-specific Nbs isolated from a screen of an Nb library derived from an alpaca immunized with SARS-CoV-2 spike glycoprotein (S); among them, three Nbs exhibited picomolar potency against SARS-CoV-2 live virus, pseudotyped viruses, and 15 circulating SARS-CoV-2 variants. To improve the efficacy, various configurations of Nbs were engineered. Nb15-NbH-Nb15, a novel trimer constituted of three Nbs, was constructed to be bispecific for human serum albumin (HSA) and RBD of SARS-CoV-2. Nb15-NbH-Nb15 exhibited sub-ng/ml neutralization potency against the wild-type and currently circulating variants of SARS-CoV-2 with a long half-life in vivo. In addition, we showed that intranasal administration of Nb15-NbH-Nb15 provided 100% protection for both prophylactic and therapeutic purposes against SARS-CoV-2 infection in transgenic hACE2 mice. Nb15-NbH-Nb15 is a potential candidate for both prevention and treatment of SARS-CoV-2 through respiratory administration.One sentence summaryNb15-NbH-Nb15, with a novel heterotrimeric bispecific configuration, exhibited potent and broad neutralization potency against SARS-CoV-2 in vitro and provided in vivo protection against SARS-CoV-2 infection in hACE2 transgenic mice via intranasal delivery.Graphical abstract:HighlightsWe described a novel heterotrimeric configuration of Nb-NbH-Nb (Nb15-NbH-Nb15) that exhibited improved viral inhibition and stability.Nb15-NbH-Nb15 provides ultrahigh neutralization potency against SARS-CoV-2 wild type and 18 mutant variants, including the current circulating variants of D614G and N501Y predominantly in the UK and South Africa.It is the first to demonstrate the Nbs efficacy in preventing and treating SARS-CoV-2 infection in hACE2 transgenic mice via intranasal delivery.

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