Tumor-specific Antibodies Research Articles

In silico investigation of a novel anti-EGFR scFv-IL-24 fusion protein induces apoptosis in malignant cells.

Epidermal growth factor receptor (EGFR), a member of the HER receptor family, is over expressed in various cancer cells. Using tumor-specific antibodies to deliver cytotoxic agents directly to the tumor cells is an effective treatment strategy. Targeted therapy by fusing anti-EGFR scFv with tumor-specific cytokines promises the emergence of a new era. We designed a novel immuno-apoptotic fusion protein, anti-EGFR scFv-IL-24, consisting of a specific cancer cell targeting antibody and recombinant cytokine IL-24 to explore its anti-cancerous potential. Amino acid sequences of both anti-EGFR scFv and IL-24 were fused using a specific rigid linker. In silico characterization of the designed fusion protein like to predict the primary, secondary, physiochemical properties, quality, and structural validation using online bioinformatic tools. The newly designed fusion protein consists of 402 amino acids that showed good quality with a predicted value of 76.7% having 81.5% residues in the most favored region as predicted by ERRAT2 and Ramachandran plot analysis. Docking and simulation studies were performed using HDOCK and Desmond module of Schrodinger. All the parameters of quality, validity, interaction analysis, and stability suggested that the fused molecule is fully operational and functional. The results of the study support that the anti-EGFR scFv-IL-24 fused protein could be proved as a novel candidate to combat cancer.

Optimization of Size of Nanosensitizers for Antitumor Radiotherapy Using Mathematical Modeling.

The efficacy of antitumor radiotherapy can be enhanced by utilizing nonradioactive nanoparticles that emit secondary radiation when activated by a primary beam. They consist of small volumes of a radiosensitizing substance embedded within a polymer layer, which is coated with tumor-specific antibodies. The efficiency of nanosensitizers relies on their successful delivery to the tumor, which depends on their size. Increasing their size leads to a higher concentration of active substance; however, it hinders the penetration of nanosensitizers through tumor capillaries, slows down their movement through the tissue, and accelerates their clearance. In this study, we present a mathematical model of tumor growth and radiotherapy with the use of intravenously administered tumor-specific nanosensitizers. Our findings indicate that their optimal size for achieving maximum tumor radiosensitization following a single injection of their fixed total volume depends on the permeability of the tumor capillaries. Considering physiologically plausible spectra of capillary pore radii, with a nanoparticle polymer layer width of 7 nm, the optimal radius of nanoparticles falls within the range of 13-17 nm. The upper value is attained when considering an extreme spectrum of capillary pores.

Cancer immune exclusion: breaking the barricade for a successful immunotherapy.

Immunotherapy has changed the course of cancer treatment. The initial steps were made through tumor-specific antibodies that guided the setup of an antitumor immune response. A new and successful generation of antibodies are designed to target immune checkpoint molecules aimed to reinvigorate the antitumor immune response. The cellular counterpart is the adoptive cell therapy, where specific immune cells are expanded or engineered to target cancer cells. In all cases, the key for achieving positive clinical resolutions rests upon the access of immune cells to the tumor. In this review, we focus on how the tumor microenvironment architecture, including stromal cells, immunosuppressive cells and extracellular matrix, protects tumor cells from an immune attack leading to immunotherapy resistance, and on the available strategies to tackle immune evasion.

Abstract 2983: Tumor-specific CD28 costimulatory bispecific antibodies enhance T cell activation in solid tumors

Abstract T cells in the tumor micro-environment require TCR/MHC engagement and co-stimulatory receptor engagement to achieve optimal activation. Solid tumor cells lack expression of CD28 ligands, so we hypothesized that activation of CD28 signaling at the T cell/tumor cell interface could enhance anti-tumor activity. We developed a CD28 bispecific platform that allows for the rapid generation of tumor-associated antigen (TAA) x CD28 bispecific antibodies that conditionally provide CD28 costimulation only in the presence of TAA and TCR engagement. Here, we present results for a set of bispecific antibodies with broad applicability across a range of solid tumors, including CEACAM5 x CD28, Trop-2 x CD28, STEAP1 x CD28, and mesothelin x CD28. We developed optimized CD28 scFv and Fabs that cover a range of affinities and are only agonistic in the context of TCR engagement. A matrix of bispecifics pairing these CD28 binders with CEACAM5, Trop-2, STEAP1, and mesothelin antibodies of varying affinities and epitopes were generated using Xencor’s XmAb® bispecific antibody platform. Activities of these bispecifics were assessed in vitro by measuring T cell proliferation, cytokine production, and cytotoxicity in co-cultures of human cancer cell lines mixed with primary human T cells. CEACAM5 x CD28, Trop-2 x CD28, STEAP1 x CD28, and mesothelin x CD28 bispecifics enhanced T cell degranulation, cytokine secretion, and cancer cell cytotoxicity only in concert with TCR engagement. IHC was used to compare TAA expression on cancer cell lines versus that found on cancer tissues, allowing categorization of cell lines as high density (tumor surrogate) or low density (normal tissue surrogate). CD28 bispecifics were identified with selective potency on high versus low expressing cell lines, suggesting a favorable therapeutic index. CD28 bispecific antibodies co-targeting CEACAM5, Trop-2, STEAP1, and mesothelin show promising activity and warrant further development across a range of solid tumors. Citation Format: Matthew A. Dragovich, Viralkumar Davra, Matthew S. Faber, Yoon Kyung Kim, Alex Nisthal, Veronica G. Zeng, Jonathan Jacinto, Juan E. Diaz, Thuy Truong, Jing Qi, Kendra N. Avery, Rumana Rashid, Sung-Hyung Lee, Seung Y. Chu, Christine Bonzon, Ruschelle Love, Matthew J. Bernett, James A. Ernst, Rena Bahjat, Norman J. Barlow, John R. Desjarlais, Michael Hedvat, Gregory L. Moore. Tumor-specific CD28 costimulatory bispecific antibodies enhance T cell activation in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2983.

Abstract 2380: Fluorescence labeling of human gastric cancer using novel tumor specific near infrared labeled antibodies

Abstract Introduction: Gastric cancer has a global incidence of ~1 million cases per year. Currently, complete surgical resection is the only opportunity for cure for patients. Bright labeling of tumor margins with tumor specific markers could improve outcomes. This report demonstrates the advantages of targeting gastric cancer with humanized anti-CEA and TAG-72 antibodies in mouse models. Methods: A cell line of human gastric cancer, MKN45, and a patient-derived tumor, KG8, were used to create xenograft models. To establish orthotopic models for each, ~1mm tumor fragments were harvested from subcutaneous models of these lines and sutured to the lesser curvature of the stomach. Humanized versions of TAG-72 (huCC44) and CEA (M5A) were conjugated to the near infrared dye IRDye800CW. IgG was conjugated to IRDye800CW and used as a control. For CEA-IR800 and IgG-IR800, mice received 50 µg IV and were imaged after 72 hours. For Tag72-IR800, mice received 75 µg IV and were imaged after 96 hours. Fluorescence imaging was performed on the mice using the LI-COR Pearl Imaging System. A tumor to background ratio (TBR) was calculated by dividing mean fluorescence intensity of the tumor versus normal gastric tissue. Results: Humanized anti-CEA and TAG-72 brightly labeled multiple mouse models of human gastric cancer (Table 1). The TBR for TAG-72 labeling of KG8 was 2.777. CEA had a superior TBR of 3.528 compared to 0.606 for the control (IgG) in KG8 models. In MKN models labelled with CEA, an excellent average TBR of 7.407 were seen compared to 0.668 for the control. Conclusion: Humanized anti-CEA and TAG-72 antibodies conjugated to near-infrared fluorescent dyes provide specific labeling of gastric cancers in orthotopic models. These tumor-specific fluorescent antibodies are promising potential clinical tools for visualization of gastric cancer margins at the time of surgical resection and improved surgical outcomes. Orthotopic Model Antibody Tumor to Background Ratio KG8 anti-TAG-72 2.777 KG8 anti-CEA 3.528 KG8 Control 0.606 MKN anti-CEA 7.407 MKN Control 0.668 Citation Format: Kristin E. Cox, Michael A. Turner, Siamak Amirfakhri, Thinzar M. Lwin, Pradipta Ghosh, Marygorret Obonyo, Kaitlyn M. Kelly, Robert M. Hoffman, Paul J. Yazaki, Michael Bouvet. Fluorescence labeling of human gastric cancer using novel tumor specific near infrared labeled antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2380.

Abstract 5067: Inhibition of CD47-SIRPα axis to enhance immunity against different molecular subtypes of breast cancer

Abstract Background: The CD47-SIRPα axis is an innate immune checkpoint that primarily regulates myeloid cells. In the context of cancer, tumor cells upregulate CD47 to engage SIRPα inhibitory signaling to block phagocytosis. Thus, inhibition of this axis may enhance myeloid cell phagocytosis and adaptive immune responses against cancer. While our previous studies identified that CD47 mAbs enhance HER2-specific mAb therapy (Tsao et al., 2019), clinical trials have revealed that CD47-targeting mAbs are associated with severe side effects of anemia and thrombocytopenia in patients. We thus hypothesized that targeting SIRPα, which is more restrictively expressed on myeloid cells, may achieve similar but less toxic treatment effects. Methods: To ascertain the impact of SIRPα inhibition against different molecular subtypes of breast cancer, we utilized and validated a novel SIRPα KO mouse, along with SIRPα mAbs in our previously utilized models of Triple-Negative Breast Cancer (TNBC) and HER2+ Breast Cancer (Crosby et al., 2018; Tsao et al., 2019). Using both in vitro and in vivo tumor models, we tested the therapeutic impact of SIRPα inhibition/blockade combined with immunogenic chemotherapy (doxorubicin) in TNBC or combined with HER2-specific mAbs in HER2+ Breast Cancer (HER2+ BC). Results: After validating the loss of SIRPα in KO mice, we found that E0771 TNBC cells had reduced rates of engraftment in SIRPα KO mice compared to controls, but comparable rates of growth once tumors were established. We then treated E0771 engrafted SIRPα KO and wildtype mice with doxorubicin. This treatment elicited tumor rejection in the majority of SIRPα KO mice (70% of injected tumors), compared to only 10% rejection in SIRPα WT mice. To study tumor antigen-specific immunity, we expressed different forms of OVA (secreted, cytoplasmic, membrane) in tumor cells. We found that membrane expressed OVA led to universal tumor rejection (10/10 mice) with high levels of OVA-specific Abs, in contrast to non-membrane expressed forms of OVA. This suggested the importance of tumor-specific Abs in eliciting tumor rejection. To specifically test the antitumor effect of tumor-specific antibodies in the context of SIRPα blockade, we evaluated the impact of a HER2 mAb (Trastuzumab) on HER2+ BC cells. We found enhanced phagocytosis and antitumor effects by SIRPα KO macrophages in comparison to wild-type macrophages, suggesting the potential of targeting SIRPα along with the use of standard-of-care mAb. Conclusion: Our study demonstrates that SIRPα loss can prevent tumor engraftment but may not have a strong effect against established tumors without secondary immune stimulation. However, addition of immunogenic cell death-eliciting chemotherapy or tumor-specific Abs promote tumor phagocytosis and stimulate anti-tumor immunity. These results support further investigation of SIRPα-targeting combination therapies for cancer. Citation Format: Xingru Ma, Zachary Hartman, Li-Chung Tsao, Tao Wang, Cong-Xiao Liu, Xiao Yang, Gangjun Lei, Junping Wei. Inhibition of CD47-SIRPα axis to enhance immunity against different molecular subtypes of breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5067.

Abstract 1588: Using glyco-engineered cells with flexible expression of tumor-associated carbohydrates for the generation of highly tumor-specific antibodies

Abstract Introduction: Highly potent therapeutic approaches require clean targets. However, the majority of antibodies in clinical development or approved for cancer therapy address protein targets that are only over-expressed in cancer and yet often show significant expression in healthy organs. Besides protein expression, glycosylation is strongly altered in cancer, reflecting changes in tumor metabolism or genetic alterations. Mutated or mislocated glycosyltransferases, glycosidases, substrates and chaperones, give rise to tumor-associated, truncated O-glycans like Thomsen-Friedenreich (TF) or Thomsen novelle (Tn) which are expressed on proteins in different carcinomas, leukemias, lymphomas and their metastases. Due to the heterogeneous nature of glycan biosynthesis, variations of glycan-structure occur at a given site of a glycoprotein, making fine-tuning of antibodies against a specific glycoprotein challenging. Therefore, Glycotope developed a cell line based platform, able to express proteins carrying distinct tumor-related glycan-structures in order to generate highly tumor-specific protein/carbohydrate combined epitope binding antibodies, thus increasing tumor selectivity of protein targeting antibodies. Experimental procedures: The presence of tumor-associated carbohydrates in cancer tissues was demonstrated by immunohistochemistry analysis. A platform comprising different glyco-engineered cell lines capable to express proteins with distinct glycoforms was developed and fully characterized. The cells’ ability to express specific protein/carbohydrate combined epitopes (GlycoTargets) with distinct carbohydrates was shown by flow cytometry, ELISA and mass spectrometry experiments. The versatile use of the platform for i) recombinant expression of GlycoTargets for the use as immunogens, ii) screening tool in antibody discovery campaigns, iii) characterization of antibody lead candidates, was shown in ELISA and flow cytometry experiments. Results: Using our glyco-engineered cells, we showcase the potential of the platform as a tool for the generation of proteins with specific glycosylation and for screening of antibodies that bind to their target protein only in combination with a specific tumor-associated glycan structure. Conclusion: Our platform enables tailored immunization and screening approaches in order to generate antibodies against specific protein/carbohydrate combined epitopes. These antibodies bind their protein target only in presence of tumor-associated carbohydrates, thereby showing markedly reduced binding to the protein expressed in healthy tissues. This cell-based platform provides the basis for target validation, antigen production, immunization and screening for highly specific antibodies, opening the field for more effective therapeutic approaches. Citation Format: Patrik Kehler, Naomi Kast, Manon Weiske, Stephanie Gurka, Timo Lischke, Johanna Gellert, Antje Danielczyk. Using glyco-engineered cells with flexible expression of tumor-associated carbohydrates for the generation of highly tumor-specific antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1588.

518 Identification of Tumor Infiltrating Leukocytes in Glioblastoma and Clinical Outcomes

INTRODUCTION: Glioblastoma (GBM) accounts for 60% of all malignant brain tumors in adults with a dismal 5-year survival rate of 5%. Treatment challenges stem from GBM’s intricate biology, therapy-resistant tumor cells, favorable milieu, invasive properties, and immunosuppressive tumor-infiltrating leukocytes (TIL). These cells are pro-repair and provide an immune inhibitory function, thereby conferring an elusive and protective phenotype to malignant cells. The clinical association with outcomes and response of these cell types to chemotherapeutics remains largely uncharacterized. METHODS: Fresh GBM tumor samples were collected. Using flow cytometry, tumor-specific and TIL-specific antibodies are used to label these cells. GBM and TIL phenotype within each sample is correlated to patient outcome to understand how those are related to the successes and failures of treatment. In addition, these cells are subjected to a different chemotherapeutics to assess their response to therapy. RESULTS: Patients’ mean age was 66.3 y, 15 patients (62%) were female. There was variable expression of EFGR and PDFRA within and between tumors. TIL represent approximately 20% of the cells in the samples. Myeloid cells represent most TIL (86%) in most samples. MGMT promoter un-methylated status was associated with high proportion of MDSC (34%) and poor survival. Correlations between TIL and GBM immunophenotypes were observed such as an inverse correlation between EGFR expression and MDSCs. Drug-screening is currently underway. CONCLUSIONS: The MDSC and EGFR inverse correlation suggests a possible relationship between tumor cells and TIL, supported by studies showing a release of pro-repair cytokines with EGFR signaling. Similarly, T-cells were positively correlated with EGFR expression. These findings strengthen the evidence of the protective role of TIL in GBM. Chemotherapeutics are being currently studied to assess impact on tumor viability.

Antitumor Immune Mechanisms of the Anti-Complement Factor H Antibody GT103.

Development of novel therapeutic antibodies that not only kill tumor cells but modulate the adaptive immune response has the potential to produce long term anti-cancer immunity and a durable clinical response. We previously reported the discovery of anti-complement factor H (CFH) autoantibodies in lung cancer patients that were associated with early stage disease and exceptional outcomes. The human monoclonal antibody GT103, produced from a single CFH autoantibody-expressing B cell of a lung cancer patient, recognizes a conformationally distinct epitope on tumor cells, kills tumor cells, and inhibits tumor growth in animal studies. Recent experiments have shown that GT103 restructures the tumor microenvironment and initiates a robust antitumoral adaptive immune response. The current study further elucidates several mechanisms by which GT103 kills tumor cells and drives the immune program. Here we show GT103 has specificity for tumor cells without binding to native soluble CFH or normal tissues. GT103 causes complement C3 split product deposition on tumor cells in vitro and in vivo, triggers antibody-dependent cellular phagocytosis, and increases translocation of the danger associated molecular pattern molecule calreticulin to the plasma membrane. We also demonstrate that GT103 causes B cell activation in vitro and in vivo, and that GT103 antitumor activity in vivo is B cell dependent. The complex mechanism of GT103, a tumor specific antibody that kills tumor cells and stimulates an immune response, supports further development of this human-derived antibody as a novel therapeutic option for patients with lung cancer.

Therapeutic implication of chimeric antigen receptor T-cell therapy for head and neck squamous cell carcinoma.

Therapeutic implication of chimeric antigen receptor T-cell therapy for head and neck squamous cell carcinoma.

Engineered antibody cytokine chimera synergizes with DNA-launched nanoparticle vaccines to potentiate melanoma suppression in vivo.

Cancer immunotherapy has demonstrated great promise with several checkpoint inhibitors being approved as the first-line therapy for some types of cancer, and new engineered cytokines such as Neo2/15 now being evaluated in many studies. In this work, we designed antibody-cytokine chimera (ACC) scaffolding cytokine mimetics on a full-length tumor-specific antibody. We characterized the pharmacokinetic (PK) and pharmacodynamic (PD) properties of first-generation ACC TA99-Neo2/15, which synergized with DLnano-vaccines to suppress in vivo melanoma proliferation and induced significant systemic cytokine activation. A novel second-generation ACC TA99-HL2-KOA1, with retained IL-2Rβ/γ binding and attenuated but preserved IL-2Rα binding, induced lower systemic cytokine activation with non-inferior protection in murine tumor studies. Transcriptomic analyses demonstrated an upregulation of Type I interferon responsive genes, particularly ISG15, in dendritic cells, macrophages and monocytes following TA99-HL2-KOA1 treatment. Characterization of additional ACCs in combination with cancer vaccines will likely be an important area of research for treating melanoma and other types of cancer.

Exosomes: The Role in Tumor Tolerance and the Potential Strategy for Tumor Therapy

Drug and radiotherapy resistance is the primary cause of treatment failure and poor prognosis in patients with tumors. Exosomes are extracellular vesicles loaded with substances such as nucleic acids, lipids, and proteins that transmit information between cells. Studies have found that exosomes are involved in tumor therapy resistance through drug efflux, promotion of drug resistance phenotypes, delivery of drug-resistance-related molecules, and regulation of anti-tumor immune responses. Based on their low immunogenicity and high biocompatibility, exosomes have been shown to reduce tumor therapy resistance by loading nucleic acids, proteins, and drugs inside xosomes or expressing tumor-specific antigens, target peptides, and monoclonal antibodies on their phospholipid bimolecular membranes. Consequently, future research on genetically engineered exosomes is expected to eliminate resistance to tumor treatment, improving the overall prognosis of patients with tumors.

Neutrophils and their friends.

Neutrophils and their friends.

Targeted Cytokine Delivery for Cancer Treatment: Engineering and Biological Effects

Anti-tumor properties of several cytokines have already been investigated in multiple experiments and clinical trials. However, those studies evidenced substantial toxicities, even at low cytokine doses, and the lack of tumor specificity. These factors significantly limit clinical applications. Due to their high specificity and affinity, tumor-specific monoclonal antibodies or their antigen-binding fragments are capable of delivering fused cytokines to tumors and, therefore, of decreasing the number and severity of side effects, as well as of enhancing the therapeutic index. The present review surveys the actual antibody-cytokine fusion protein (immunocytokine) formats, their targets, mechanisms of action, and anti-tumor and other biological effects. Special attention is paid to the formats designed to prevent the off-target cytokine-receptor interactions, potentially inducing side effects. Here, we describe preclinical and clinical data and the efficacy of the antibody-mediated cytokine delivery approach, either as a single therapy or in combination with other agents.

How B cells drive T-cell responses: A key role for cross-presentation of antibody-targeted antigens.

In this review we discuss an underexposed mechanism in the adaptive immune system where B cell and T cell immunity collaborate. The main function of B cell immunity is the generation of antibodies which are well known for their high affinity and antigen-specificity. Antibodies can bind antigens in soluble form making so-called immune complexes (ICs) or can opsonize antigen-exposing cells or particles for degradation. This leads to well-known effector mechanisms complement activation, antibody-dependent cytotoxicity and phagocytosis. What is less realized is that antibodies can play an important role in the targeting of antigen to dendritic cells (DCs) and thereby can drive T cell immunity. Here we summarize the studies that described this highly efficient process of antibody-mediated antigen uptake in DCs in vitro and in vivo. Only very low doses of antigen can be captured by circulating antibodies and subsequently trapped by DCs in vivo. We studied the handling of these ICs by DCs in subcellular detail. Upon immune complex engulfment DCs can sustain MHC class I and II antigen presentation for many days. Cell biological analysis showed that this function is causally related to intracellular antigen-storage compartments which are functional endolysosomal organelles present in DCs. We speculate that this function is immunologically very important as DCs require time to migrate from the site of infection to the draining lymph nodes to activate T cells. The implications of these findings and the consequences for the immune system, immunotherapy with tumor-specific antibodies and novel vaccination strategies are discussed.

The Application of Nanotechnology in Enhancing Immunotherapy for Cancer Treatment: Future Aspects

Nanotechnology is the investigation of matter at the molecular and atomic levels. It identifies and discovers the beneficial features at the nanoscale level. There are numerous applications of nanotechnology in modern science. Medicinal field has great impact of modern nanoscience. Nano disks, high density lipoprotein nanostructures, and gold nanoparticles are different example of nanotechnology applied in drug delivery system. The growing discipline of this nanotechnology fulfilled the demand for innovative methods in the detection and treatment of cancer. With the help of this advanced technology several functional molecules can be conjugated simultaneously such as tumor-specific ligands, antibodies, anticancer drugs, and imaging probes etc. Nanoparticles are biocompatible and biodegradable in nature. They act as a carrier, which target particular sites of cancer cell. Since, nanoparticles are 100-1000 times smaller than cancer cells, they can readily pass through leaky blood vessels. They can easily interact with tumor-specific proteins both on the outside and inside of cancer cells. This advance nanotechnology has brought a new hope for developing treatment of cancer therapy. In this article, we highlighted a review on the recent applications of nanoscience in enhancing immunotherapy and the treatment of cancerous cells.

BCL11B depletion induces the development of highly cytotoxic innate T cells out of IL-15 stimulated peripheral blood αβ CD8+ T cells

ABSTRACT BCL11B, an essential transcription factor for thymopoiesis, regulates also vital processes in post-thymic lymphocytes. Increased expression of BCL11B was recently correlated with the maturation of NK cells, whereas reduced BCL11B levels were observed in native and induced T cell subsets displaying NK cell features. We show that BCL11B-depleted CD8+ T cells stimulated with IL-15 acquired remarkable innate characteristics. These induced innate CD8+ (iiT8) cells expressed multiple innate receptors like NKp30, CD161, and CD16 as well as factors regulating migration and tissue homing while maintaining their T cell phenotype. The iiT8 cells effectively killed leukemic cells spontaneously and neuroblastoma spheroids in the presence of a tumor-specific monoclonal antibody mediated by CD16 receptor activation. These iiT8 cells integrate the innate natural killer cell activity with adaptive T cell longevity, promising an interesting therapeutic potential. Our study demonstrates that innate T cells, albeit of limited clinical applicability given their low frequency, can be efficiently generated from peripheral blood and applied for adoptive transfer, CAR therapy, or combined with therapeutic antibodies.

Anti-tumor antibody isotype response can be modified with locally administered immunoadjuvants

In situ vaccination with immunostimulatory compounds is a demonstrated means to treat tumors preclinically. While these therapeutic effects have been attributed to the actions of T cells or innate immune activation, characterisation of the humoral immune response is seldom performed. This study aims to identify whether the injection of immunoadjuvants, Addavax (Adda) and cytosine-phosphorothioate-guanine oligodeoxynucleotide (CpG), intratumorally can influence the antibody response. Specifically, whether intratumoral injection of immunoadjuvants can alter the tumor-specific antibody target, titre and isotype. Following this, the study aimed to investigate whether serum obtained from in situ vaccinated mice could neutralise circulating tumor cells. Serum was obtained from mice bearing B16F10-OVA-Luc-GFP tumors treated with immunoadjuvants. Antibody targets’ titre and isotype were assessed by indirect ELISA. The ability of serum to neutralise circulating cancer cells was evaluated in a B16F10 pseudo-metastatic model. It was observed that tumor-bearing mice mount a specific anti-tumor antibody response. Antibody titre and target were unaffected by in situ vaccination with immunoadjuvants; however, a higher amount of IgG2c was produced in mice receiving Adda plus CpG. Serum from in situ vaccinated mice was unable to neutralise circulating B16F10 cells. Thus, this study has demonstrated that anti-tumor antibody isotype may be modified using in situ vaccination; however, this alone is not sufficient to neutralise circulating cancer cells.Graphical

Tumor targeted 4-1BB agonist antibody-albumin fusions with high affinity to FcRn induce anti-tumor immunity without toxicity

SummaryCostimulation of tumor-infiltrating T lymphocytes by anti-4-1BB monoclonal antibodies (mAbs) has shown anti-tumor activity in human trials, but can be associated with significant off-tumor toxicities involving FcγR interactions. Here, we introduce albumin-fused mouse and human bispecific antibodies with clinically favorable pharmacokinetics designed to confine 4-1BB costimulation to the tumor microenvironment. These Fc-free 4-1BB agonists consist of an EGFR-specific VHH antibody, a 4-1BB-specific scFv, and a human albumin sequence engineered for high FcRn binding connected in tandem (LiTCo-Albu). We demonstrate in vitro cognate target engagement, EGFR-specific costimulatory activity, and FcRn-driven cellular recycling similar to non-fused FcRn high-binding albumin. The mouse LiTCo-Albu exhibited a prolonged circulatory half-life and in vivo tumor inhibition, with no indication of 4-1BB mAb-associated toxicity. Furthermore, we show a greater therapeutic effect when used in combination with PD-1-blocking mAbs. These findings demonstrate the feasibility of tumor-specific LiTCo-Albu antibodies for safe and effective costimulatory strategies in cancer immunotherapy.

Immunotherapy for cancer treatment.

Immunotherapy is an effective way to treat many diseases associated with disorders of the immune system by modulating immune response. It involves several ways of manipulating the immune system, which either suppress the immune response or, on the contrary, stimulates it. Immunotherapy is currently of immense importance not only in the context of the treatment of autoimmune diseases and immunodeficiencies, but it is also a promising method for treating cancer. Efforts to use the bodys own anti-tumor response have led to the discovery of alternative treatments for cancer. The aim of this paper is to provide a literature review focused on the current possibilities of cancer immunotherapy. In addition to classical procedures such as chemotherapy and radiotherapy, treatments consisting of adoptive cell therapy and blockade of immune checkpoints are being increasingly indicated. The latest form of adoptive cell therapy is the use of T-lymphocytes expressing chimeric antigen receptors. This type of treatment is indicated for hematological cancers. In recent years, a new approach to the treatment of cancer has emerged using blockade of immune checkpoints by monoclonal antibodies. At present, antitumor therapy focuses on blocking of inhibitory molecules - cytotoxic T-lymfocyte antigen 4 (CTLA-4) and programmed cell death 1 (PD-1). Administration of anti-CTLA-4 receptor specific monoclonal antibodies blocks binding between CTLA-4 receptors and B7 ligands, thereby preventing inhibition of activated cytotoxic T cells. Another type of checkpoints of the immune response include PD-1 molecules expressed on the surface of T-lymphocytes, B-lymphocytes, but also on the surface of myeloid cells. Blockade of PD-1 receptors and PD-L1 ligands prevents the inhibition of T-lymphocytes by tumor cells, leading to an increase in the immune systems ability to recognize tumor cells and subsequently destroy them. Blockade of PD-1 receptors and PD-L1 ligands prevents the inhibition of T-lymphocytes by tumor cells, leading to an increased immune response to the recognition of tumor cells and their subsequent destruction. An alternative form of tumor treatment is the administration of tumor vaccines and tumor-specific monoclonal antibodies (mAbs). The use of mAbs to kill tumors requires the expression of tumor-specific antigens on the surface of tumor cells. Through these receptors, mAb targets cytotoxic cells, toxins, drugs, or radioisotopes to tumor cells and thereby destroys them. Also, mAbs are able to block angiogenesis, which is crucial in tumor cell proliferation.