Monoclonal antibodies (mAbs) are now a fundamental component of immunology and biotechnology, with a wide range of uses in applied biology, immunology, biochemistry, and other scientific domains. The hybridoma technique, invented in 1975 by Cesar Milstein and Georges Kohler, revolutionized the production of mAbs. Since then, numerous studies have revealed a wide range of applications for monoclonal antibodies (mAbs), with clinical medicine experiencing the most significant impact. mAbs are now essential in the treatment of conditions like breast cancer, psoriasis, arthritis, leukemia, and transplant rejection. The rise in late-stage clinical trials and their expanded role in modern treatments provide evidence of their growing prominence. Biological agents have become a viable treatment option for cancer and chronic immune-mediated diseases in addition to mAbs. These medications have proven very helpful in treating allergic and immune-mediated disorders, even though they have been linked to infusion reactions and immune-related adverse effects, especially when anti-drug antibodies are involved. Additionally, these treatments are essential for improving immune surveillance against cancer. These biological agents' safety profiles are continually improving, particularly for chronic illnesses, providing patients with safer treatment options. mAbs have developed over the last thirty years from lab instruments to life-saving medications. The 1986 approval of Muromonab CD3 and the 1997 approval of Rituximab for B-cell lymphoma were significant turning points. About 60 therapeutic mAbs, including chimeric, humanized, and fully human versions, had received Food and Drug Administration (FDA) approval in March 2017. mAbs are now authorized to cure several conditions, including cancer, heart disease, and autoimmune disorders, as a result of these regulatory developments. Additionally, mAbs have shown promise in the treatment of hematologic malignancies, especially cutaneous lymphomas, with clinical trials demonstrating good efficacy and safety profiles. Their incorporation into stepwise regimens or combination therapies continues to improve treatment outcomes.

OKT3 is a murine monoclonal antibody (mAb) directed against human CD3 expressed on T cells and is known to induce T cell activation followed by activation-induced cell death. This study investigated the role of canonical Wnt signaling in OKT3-mediated T cell activation and apoptosis using preclinical models. In primary human PBMCs, OKT3 treatment downregulated the expression of canonical Wnt signaling-related genes, whereas the Wnt pathway activator CHIR99021 upregulated their expression and reversed the OKT3-induced suppression. OKT3 stimulation upregulated T cell activation markers (CD69, CD25), particularly in CD8[+] T cells, and induced apoptosis as assessed by flow cytometry. Co-treatment with CHIR99021 attenuated OKT3-induced CD25 expression and late apoptosis, suggesting that Wnt signaling modulates T cell activation and cell death. In a humanized mouse model, OKT3 administration led to marked depletion of hCD3[+], hCD4[+], and hCD8[+] T cells in the peripheral blood. Transcriptomic profiling using RNA-seq of liver-infiltrating human immune cells revealed significant upregulation of genes involved in T cell activation, apoptosis, cytokine signaling, and oxidative stress, accompanied by widespread downregulation of Wnt signaling genes (CTNNB1, LRP6, DVL1, FZD family). Therefore, these findings suggest that OKT3 induces T cell responses characterized by activation and subsequent apoptosis, in association with Wnt signaling. This study provides mechanistic insight into OKT3-mediated immunomodulation and supports preclinical evaluation of T cell-targeting monoclonal antibodies.

CD3ε is an essential subunit of the T-cell receptor complex. It is required for T cell activation and immune modulation. Dysregulated CD3ε signaling results in abnormal T cell activation, contributing to the pathogenesis of various immune-related disorders, including autoimmune diseases. Although anti-CD3ε antibodies, such as muromonab-CD3, can effectively modulate T cell responses, their use is often limited by severe adverse effects caused by excessive T cell activation. In this study, we present K108.5, a fully human monoclonal antibody (mAb) specific to human CD3ε (hCD3ε), designed to modulate T cell activity without inducing undesired activation. Using phage display technology, we identified five hCD3ε-specific mAbs. Of these, K108.5 exhibited the highest binding affinity (KD = 2.4 nM) to hCD3ε. It recognized a different epitope of hCD3ε, distinct from muromonab-CD3. Moreover, unlike muromonab-CD3, K108.5 did not induce T cell activation. It promoted the rapid internalization of CD3ε, resulting in its downregulation on the T cell surface. K108.5 also inhibited T cell activation induced by dendritic cells or muromonab-CD3 engagement. These findings suggest that K108.5 may be effective in modulating T cell activity under conditions of T cell dysregulation.

Studies have shown that patients who undergo heart transplantation (HTx) are at an increased risk for developing skin cancer. This condition can add physiological and psychological burden to patients. Therefore, assessing the incidence and identifying risk factors for skin cancer are crucial steps in its prevention. The purpose of this skin study is to systematically evaluate the incidence and risk factors of skin cancer in HTx. Two researchers independently conducted literature searches across 8 databases. The search covered publications from the establishment of the database through October 1, 2024. After screening title, abstract, and the full text, 34 eligible cohort studies were included. The studies were evaluated using the New castle-Ottawa Scale (NOS) for non-randomized studies, and papers selection followed PRISMA guidelines. The meta-analysis was conducted using the Stata 15.0 software. Among 34 cohort studies on HTx, the pooled incidence of skin cancer was 16% (95% CI: 14-19%). The incidences by type were 10% (95% CI: 8-12%) for squamous cell carcinoma and 8% (95% CI: 6-9%) for basal cell carcinoma. Regionally, the highest incidence was observed in the USA 22% (95% CI: 18-27%). Risk factors significantly associated with skin cancer included age (RR: 1.08, 95% CI: 1.04-1.11), male (RR: 1.53, 95% CI:1.11-2.12), white race (RR: 10.23, 95% CI: 7.32-14.30), smoking history (RR:1.26, 95% CI:1.05-1.51), prolonged sunlight exposure (≥ 2500 h) (RR:3.66, 95% CI: 2.11-6.36), pre-transplant cancer (RR: 1.61, 95% CI: 1.43-1.82), muromonab-CD3 (OKT3) (RR: 2.61, 95% CI: 2.11-3.24). The higher incidence of skin cancer observed in this study highlights the urgent need for follow-up care in heart transplant recipients. To address this, tailored skin cancer prevention strategies should be implemented, focusing on modifiable risk factors. Our findings provide a theoretical foundation to help healthcare professionals prevent and manage skin cancer in heart transplant patients.Patient or Public Contribution: YY, and HPY, were responsible for the conception and design of the study. YYS, FYL, and HPY, were responsible for the acquisition, analysis and interpretation of the data. All of the authors drafted the article or revised it critically for important intellectual content and provided final approval of the version to be submitted.

This phase 3 trial of PROTECT confirms the beneficial effects of teplizumab (anti-CD3 treatment) in type 1 diabetes and expands the indications from diabetes prevention (stage 2) to early treatment (stage 3). More efforts are needed to confirm the effects in the general population, with a higher dose, and with repeated dosing.

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune condition characterized by the irreversible destruction of the β cells of the pancreas, which leads to a lifelong dependency on exogenous insulin. Despite the advancements in insulin delivery methods, the suboptimal outcomes of these methods have triggered the search for therapies that may prevent or reverse the disease. Given the autoimmune aetiology of T1DM, therapies counteracting the immune-mediated destruction of the β-cells are the obvious target. Although several treatment strategies have been attempted to target cellular, humoral and innate immunity, very few have had a clinically meaningful impact. Of all the available immunomodulatory agents, cluster of differentiation (CD) 3 antibodies have exhibited the most promising preclinical and clinical results. Muromonab-CD3, which also happened to be a murine CD3 antibody, was the first monoclonal antibody approved for clinical use and was primarily indicated for graft rejection. The adverse effects associated with muromonab-CD3 led to its withdrawal. Teplizumab, a newer CD3 antibody, has a better side-effect profile because of its humanized nature and non-Fc-receptor-binding domain. In November 2022, teplizumab became the first immunomodulatory agent to be licensed by the US Food and Drug Administration for delaying the onset of T1DM in high-risk adults and children over 8 years old. The mechanism seems to be enhancing regulatory T-cell activity and promoting immune tolerance. This article reviews the mechanism of action and the clinical trials of teplizumab in individuals with T1DM or at risk of developing the disease.

Amphiregulin (AREG) is a ligand of the epidermal growth factor receptor (EGFR) and has been shown to regulate the phagocytosis-induced cell death of monocytes in peripheral blood. AREG-dependent apoptotic signaling engages factors of the intrinsic and extrinsic apoptotic pathway, such as BCL-2, BCL-XL, and death ligand/receptor CD95/CD95L. Here, we tested the hypothesis that AREG influences costimulatory monocyte functions, which are crucial for T-cell responses. We found a stronger expression of AREG and EGFR in monocytes compared to lymphocytes. As a novel function of AREG, we observed reduced T-cell proliferation following polyclonal T-cell stimulation with OKT3. This reduction of proliferation occurred in the presence of monocytes as well as in their absence, monocyte signaling being replaced by crosslinking of OKT3. Increasing concentrations of AREG down-modulated the concentration of costimulatory B7 molecules (CD80/CD86) and HLA-DR on monocytes. In proliferation assays, CD28 expression on T cells was down-modulated on the application of OKT3 but unaltered by AREG. LcK activation, following OKT3-stimulation, was reduced in T cells that had been coincubated with AREG. The effects of AREG on T-cell phenotypes were also present when monocytes were depleted and OKT3 was crosslinked. The rearranged expression of immunological synapse proteins was accompanied by an alteration of T-cell polarization. Although the proportion of regulatory T cells was not shifted by AREG, IL-17-expressing T cells were significantly enhanced, with a bias toward TH1-polarization. Taken together, these results suggest that AREG acts as an immunoregulatory molecule at the interface between antigen-presenting cells and T cells.

Bispecific T cell engaging antibodies (bsAbs) have emerged as novel and powerful therapeutic agents for redirecting T cells towards antigen-specific tumor killing. The cell surface glycoprotein and SLAM family member, CS1, exhibits stable and high-level expression on malignant plasma cells including multiple myeloma, which is indicative of an ideal target for bsAb therapy. Here, we developed a CS1 bsAb (CS1-dbBiTE) using Click chemistry to conjugate intact anti-CS1 antibody (Elotuzumab) and anti-huOKT3 antibody at their respective hinge regions. Using a cellular therapy approach, human T cells were armed ex-vivo with CS1-dbBiTE prior to examining effector activity. Our data indicates that arming T cells with CS1-dbBiTE induced T cell activation and expansion and subsequent cytotoxic activity against CS1-bearing MM tumors, demonstrated by significant CD107a expression as well as inflammatory cytokine secretion. As expected, CS1-dbBiTE armed T cells showed significantly reduced effector activity in the absence of CS1 expression. Similarly, in MM mouse xenograft studies, armed T cells exhibited effective anti-tumor efficacy highlighted by reduced tumor burden in MM.1S tumor-bearing mice compared to controls. On the basis of these findings, the rationale for CS1 targeting by human T cells armed with CS1-dbBiTE presents a potentially effective therapeutic approach for targeting MM.

Immunotherapy has some shortcomings such as off-target toxicity, treatment time and poor immunogenicity, which limit its therapeutic effect. Nanomaterials are particularly attractive in immunotherapy due to their drug delivery capabilities. Nano drug delivery system loaded with Toll-like receptor (TLR) agonist imiquimod (IMQ) and CD3 immune antibody OKT3 is constructed by using polydopamine (PDA) and CaCO3. While PDA-IMQ@CaCO3-OKT3 (PICO NPs) drug delivery system has the advantages of high biocompatibility, low toxicity, degradability. Antitumor studies in vitro and in vivo have shown that the system can effectively inhibit the proliferation of mouse breast cancer cells and the activity of Regulatory T Cells (Tregs), activate immunogenic cell death (ICD), and enhance the activity of antigen-presenting cells (APCs). Effectively eliminate tumor immunosuppression and fully activate immune function.

Since the advent of hybridoma technology in the year 1975, it took a decade to witness the first approved monoclonal antibody Orthoclone OKT39 (muromonab-CD3) in the year 1986. Since then, continuous strides have been made to engineer antibodies for specific desired effects. The engineering efforts were not confined to only the variable domains of the antibody but also included the fragment crystallizable (Fc) region that influences the immune response and serum half-life. Engineering of the Fc fragment would have a profound effect on the therapeutic dose, antibody-dependent cell-mediated cytotoxicity as well as antibody-dependent cellular phagocytosis. The integration of computational techniques into antibody engineering designs has allowed for the generation of testable hypotheses and guided the rational antibody design framework prior to further experimental evaluations. In this article, we discuss the recent works in the Fc-fused molecule design that involves computational techniques. We also summarize the usefulness of in silico techniques to aid Fc-fused molecule design and analysis for the therapeutics application.

CD19 CAR-T (chimeric antigen receptor-T) cell immunotherapy achieves a remission rate of approximately 70% in recurrent and refractory lymphoma treatment. However, the loss or reduction of CD19 antigen on the surface of lymphoma cells results in the escape of tumor cells from the immune killing of CD19 CAR-T cells (CAR19-T). Therefore, novel therapeutic strategies are urgently required. In this study, an anti-CD79b/CD3 bispecific antibody (BV28-OKT3) was constructed and combined with CAR19-T cells for B-cell lymphoma treatment. When the CD19 antigen was lost or reduced, BV28-OKT3 redirected CAR19-T cells to CD79b+ CD19- lymphoma cells; therefore, BV28-OKT3 overcomes the escape of CD79b+ CD19- lymphoma cells by the killing action of CAR19-T cells in vitro and in vivo. Furthermore, BV28-OKT3 triggered the antitumor function of CAR- T cells in the infusion product and boosted the antitumor immune response of bystander T cells, markedly improving the cytotoxicity of CAR19-T cells to lymphoma cells in vitro and in vivo. In addition, BV28-OKT3 elicited the cytotoxicity of donor-derived T cells toward lymphoma cells in vitro, which depended on the presence of tumor cells. Therefore, our findings provide a new clinical treatment strategy for recurrent and refractory B-cell lymphoma by combining CD79b/CD3 BsAb with CAR19-T cells.

CD30 is expressed on Hodgkin lymphomas (HL), many non-Hodgkin lymphomas (NHLs), and non-lymphoid malignancies in children and adults. Tumor expression, combined with restricted expression in healthy tissues, identifies CD30 as a promising immunotherapy target. An anti-CD30 antibody-drug conjugate (ADC) has been approved by the FDA for HL. While anti-CD30 ADCs and chimeric antigen receptors (CARs) have shown promise, their shortcomings and toxicities suggest that alternative treatments are needed. We developed novel anti-CD30 x anti-CD3 bispecific antibodies (biAbs) to coat activated patient T cells (ATCs) ex vivo prior to autologous re-infusions. Our goal is to harness the dual specificity of the biAb, the power of cellular therapy, and the safety of non-genetically modified autologous T cell infusions. We present a comprehensive characterization of the CD30 binding and tumor cell killing properties of these biAbs. Five unique murine monoclonal antibodies (mAbs) were generated against the extracellular domain of human CD30. Resultant anti-CD30 mAbs were purified and screened for binding specificity, affinity, and epitope recognition. Two lead mAb candidates with unique sequences and CD30 binding clusters that differ from the ADC in clinical use were identified. These mAbs were chemically conjugated with OKT3 (an anti-CD3 mAb). ATCs were armed and evaluated in vitro for binding, cytokine production, and cytotoxicity against tumor lines and then in vivo for tumor cell killing. Our lead mAb was subcloned to make a Master Cell Bank (MCB) and screened for binding against a library of human cell surface proteins. Only huCD30 was bound. These studies support a clinical trial in development employing ex vivo-loading of autologous T cells with this novel biAb.