Activation and expansion of human T cells using artificial antigen-presenting cell scaffolds

Biomaterial-Driven 3D Scaffolds for Immune Cell Expansion toward Personalized Immunotherapy

Immunotherapy has emerged as a transformative medical approach in recent years, providing novel treatments for cancer eradication, autoimmune disorders, and infectious diseases. Fundamental to the success of therapy is the enrichment of the immune cell population, particularly T cells, natural killer cells, and dendritic cells. However, achieving a robust and long-term proliferation of immune cells is still challenging both in vivo and ex vivo. In vivo expansion leverages the patient's natural microenvironment and regulatory mechanisms through therapeutic interventions like immune checkpoint inhibitors, cytokine therapy, and targeted antibodies. This approach fosters long-term immune memory and sustained protection. In contrast, ex vivo expansion involves isolation, manipulation, and expansion of the immune cells under controlled conditions before reinfusion, allowing for precise control over the process and generating potent immune cell populations. Hydrogels, due to their tunable biomechanical properties, high biocompatibility, and ability to mimic the extracellular matrix, provide an ideal platform for both in vivo and ex vivo immune cell expansion. For instance, hydrogel-based scaffolds or beads can facilitate a controlled and efficient expansion of immune cells ex vivo, whereas injectable and implantable hydrogels can provide innovative solutions for enhancing immune cell activity within the patient supporting prolonged immune cell activity. This review aims to elucidate the importance of hydrogel-based strategies in immune cell expansion, advancing the development of effective, personalized immunotherapies to improve patient outcomes. STATEMENT OF SIGNIFICANCE: This review highlights the transformative potential of hydrogel-based 3D scaffolds in advancing personalized immunotherapy. By integrating in vivo and ex vivo strategies, hydrogels provide an innovative platform to enhance immune cell expansion, addressing critical challenges in immunotherapy. The discussion emphasizes the unique biomechanical and biochemical tunability of hydrogels, enabling precise mimicry of the extracellular matrix to support T cell proliferation, activation, and memory formation. These advances offer scalable, cost-effective solutions for producing high-quality immune cells, contributing to more effective cancer treatments, autoimmune disease management, and infectious disease control. By bridging materials science and immunology, this work underscores the pivotal role of hydrogels in shaping the future of immune-based therapies.

Radiotherapy-resistant prostate cancer cells escape immune checkpoint blockade through the senescence-related ataxia telangiectasia and Rad3-related protein

BACKGROUND

The majority of patients with prostate cancer (PCa) exhibit intrinsic resistance to immune checkpoint blockade (ICB) following radiotherapy (RT). This resistance is generally attributed to the limited antigen presentation of heterogeneous cells within tumors. Here, we aimed to isolate and characterize these diverse subgroups of tumor post-RT to understand the molecular mechanisms of their resistance to ICB.

METHODS

Single-cell RNA-sequencing (scRNA-seq) was used to profile senescent cancer cell clusters induced by RT in LNCaP cells. The expression and phosphorylation levels of ataxia telangiectasia and Rad3-related protein (ATR) were assessed by immunohistochemistry in clinical samples from patients with or without RT. Co-immunoprecipitation, mutagenesis, and Western blotting were used to measure the interactions between proteins. Xenograft experiments were performed to assess the tumor immune response in the mice.

RESULTS

We identified a subset of PCa cells that exhibited resistance to RT, characterized by a reduced antigen presentation capability, which enhanced their ability to evade immune detection and resist cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) blockade. scRNA-seq revealed that the senescent state was a transient phase of PCa cells post-RT, particularly in CTLA-4 blockade treatment-resistant cells. This state was marked by increased cytosolic ATR level. Cytosolic ATR phosphorylated CD86 in its cytosolic domain and enhanced the interaction between CD86 and its E3 ligase MARCH1 through electrostatic attraction. Depletion or inhibition of Atr increased the sensitivity to immune attack and improved responses to anti-Ctla-4 antibody treatment in a mouse model.

CONCLUSIONS

Our findings indicate that the activation of cytosolic ATR, which is associated with cellular senescence, impedes the effectiveness of combined RT and ICB treatments. This discovery may provide valuable insights for improving the efficacy of combined RT and ICB therapies in PCa.

Subcutaneous biodegradable scaffolds for restimulating the antitumour activity of pre-administered CAR-T cells

The efficacy of adoptive T-cell therapies based on chimaeric antigen receptors (CARs) is limited by the poor proliferation and persistence of the engineered T cells. Here we show that a subcutaneously injected biodegradable scaffold that facilitates the infiltration and egress of specific T-cell subpopulations, which forms a microenvironment mimicking features of physiological T-cell activation, enhances the antitumour activity of pre-administered CAR-T cells. CAR-T-cell expansion, differentiation and cytotoxicity were driven by the scaffold's incorporation of co-stimulatory bound ligands and soluble molecules, and depended on the types of co-stimulatory molecules and the context in which they were presented. In mice with aggressive lymphoma, a single, local injection of the scaffold following non-curative CAR-T-cell dosing led to more persistent memory-like T cells and extended animal survival. Injectable biomaterials with optimized ligand presentation may boost the therapeutic performance of CAR-T-cell therapies.

Biomimetic cell stimulation with a graphene oxide antigen-presenting platform for developing T cell-based therapies

Chimeric antigen receptor (CAR)-engineered T cells represent a front-line therapy for cancers. However, the current CAR T cell manufacturing protocols do not adequately reproduce immunological synapse formation. Here, in response to this limitation, we have developed a flexible graphene oxide antigen-presenting platform (GO-APP) that anchors antibodies onto graphene oxide. By decorating anti-CD3 (αCD3) and anti-CD28 (αCD28) on graphene oxide (GO-APP3/28), we achieved remarkable T cell proliferation. In vitro interactions between GO-APP3/28 and T cells closely mimic the in vivo immunological synapses between antigen-presenting cells and T cells. This immunological synapse mimicry shows a high capacity for stimulating T cell proliferation while preserving their multifunctionality and high potency. Meanwhile, it enhances CAR gene-engineering efficiency, yielding a more than fivefold increase in CAR T cell production compared with the standard protocol. Notably, GO-APP3/28 stimulated appropriate autocrine interleukin-2 (IL-2) in T cells and overcame the in vitro reliance on external IL-2 supplementation, offering an opportunity to culture T cell-based products independent of IL-2 supplementation.

Personalized nanovaccines for treating solid cancer metastases

Cancer vaccines have garnered attention as a potential treatment for cancer metastases. Nevertheless, the clinical response rate to vaccines remains < 30%. Nanoparticles stabilize vaccines and improve antigen recognition and presentation, resulting in high tumor penetration or accumulation, effective co-distribution of drugs to the secondary lymphatic system, and adaptable antigen or adjuvant administration. Such vaccine-like nanomedicines have the ability to eradicate the primary tumors as well as to prevent or eliminate metastases. This review examines state-of-the-art nanocarriers developed to deliver tumor vaccines to metastases, including synthetic, semi-biogenic, and biogenic nanosystems. Moreover, it highlights the physical and pharmacological properties that enhance their anti-metastasis efficiency. This review also addresses the combination of nanovaccines with cancer immunotherapy to target various steps in the metastatic cascade, drawing insights from preclinical and clinical studies. The review concludes with a critical analysis of the challenges and frameworks linked to the clinical translation of cancer nanovaccines.

In Situ Tumor-Infiltrating Lymphocyte Therapy by Local Delivery of an mRNA Encoding Membrane-Anchored Anti-CD3 Single-Chain Variable Fragment

Tumor-infiltrating lymphocyte (TIL) therapy has shown promising responses in clinical trials for highly aggressive cancers such as advanced melanoma and metastatic colorectal cancer. However, TIL therapy is still limited in clinical practice due to the complex ex vivo cell preparation process. Here, we report an "in situ TIL therapy" for the treatment of solid tumors. We utilized lipid nanoparticles for the delivery of an mRNA encoding membrane-anchored anti-CD3 single-chain variable fragment (scFv) (MA-aCD3), efficiently engineering both tumor-associated macrophages (TAMs) and tumor cells following intratumoral delivery. Expression of MA-aCD3 resulted in enhanced TIL activation, proliferation, and tumor cell engagement directly within the tumor microenvironment. In B16F10 and MC38 tumor models, concurrent expression of MA-aCD3 on TAMs and tumor cells mediated by mRNA delivery resulted in significant antitumor effects via in situ polyclonal CD8+ TIL expansion and directed cytotoxic effector functions. In addition, combinatorial treatment of MA-aCD3-encoding mRNA and antiprogrammed cell death 1 (anti-PD-1) antibodies exhibited synergistic antitumor effects on anti-PD-1 refractory B16F10 tumors. Together, our findings suggest that in situ TIL therapy is a practical and effective mRNA-based therapeutic modality for the treatment of solid tumors.

Cell surface morphology mimicking nano-bio platform for immune cell stimulation

Studying the complex realm of cellular communication and interactions by fluorescence microscopy requires sample fixation on a transparent substrate. To activate T cells, which are pivotal in controlling the immune system, it is important to present the activating antigen in a spatial arrangement similar to the nature of the antigen-presenting cell, including the presence of ligands on microvilli. Similar arrangement is predicted for some other immune cells. In this work, immune cell-stimulating platform based on nanoparticle-ligand conjugates have been developed using a scalable, affordable, and broadly applicable technology, which can be readily deployed without the need for state-of-the-art nanofabrication instruments. The validation of surface biofunctionalization was performed by combination of fluorescence and atomic force microscopy techniques. We demonstrate that the targeted system serves as a biomimetic scaffold on which immune cells make primary contact with the microvilli-mimicking substrate and exhibit stimulus-specific activation.

Focusing on exosomes to overcome the existing bottlenecks of CAR-T cell therapy

Since chimeric antigen receptor T (CAR-T) cells were introduced three decades ago, the treatment using these cells has led to outstanding outcomes, and at the moment, CAR-T cell therapy is a well-established mainstay for treating CD19 + malignancies and multiple myeloma. Despite the astonishing results of CAR-T cell therapy in B-cell-derived malignancies, several bottlenecks must be overcome to promote its safety and efficacy and broaden its applicability. These bottlenecks include cumbersome production process, safety concerns of viral vectors, poor efficacy in treating solid tumors, life-threatening side effects, and dysfunctionality of infused CAR-T cells over time. Exosomes are nano-sized vesicles that are secreted by all living cells and play an essential role in cellular crosstalk by bridging between cells. In this review, we discuss how the existing bottlenecks of CAR-T cell therapy can be overcome by focusing on exosomes. First, we delve into the effect of tumor-derived exosomes on the CAR-T cell function and discuss how inhibiting their secretion can enhance the efficacy of CAR-T cell therapy. Afterward, the application of exosomes to the manufacturing of CAR-T cells in a non-viral approach is discussed. We also review the latest advancements in ex vivo activation and cultivation of CAR-T cells using exosomes, as well as the potential of engineered exosomes to in vivo induction or boost the in vivo proliferation of CAR-T cells. Finally, we discuss how CAR-engineered exosomes can be used as a versatile tool for the direct killing of tumor cells or delivering intended therapeutic payloads in a targeted manner.

Three-dimensional isotropic imaging of live suspension cells enabled by droplet microvortices

Fast, nondestructive three-dimensional (3D) imaging of live suspension cells remains challenging without substrate treatment or fixation, precluding scalable single-cell morphometry with minimal alterations. While optical sectioning techniques achieve 3D live cell imaging, lateral versus depth resolution differences further complicate analysis. We present a scalable microfluidic method capable of 3D fluorescent isotropic imaging of live, nonadherent cells suspended inside picoliter droplets with high-speed single-cell volumetric readout (800 to 1,200 slices in 5 to 8 s) and near-diffraction limit resolution (~216 nm). The platform features a droplet trap array that leverages flow-induced droplet interfacial shear to generate intradroplet microvortices, which rotate single cells on their axis to enable optical projection tomography (OPT)-based imaging. This allows gentle (~1 mPa shear stress) observation of cells encapsulated inside nontoxic isotonic buffer droplets, facilitating scalable OPT acquisition by simultaneous spinning of hundreds of cells. We demonstrate 3D imaging of live myeloid and lymphoid cells in suspension, including K562 cells, as well as naive and activated T cells-small cells prone to movement in their suspended phenotype. Our fully suspended, orientation-independent cell morphometry, driven by isotropic imaging and spherical harmonic analysis, enabled the study of primary T cells across various immunological activation states. This approach unveiled six distinct nuclear content distributions, contrasting with conventional 2D images that typically portray spheroid and bean-like nuclear shapes associated with lymphocytes. Our arrayed-droplet OPT technology is capable of isotropic, single live-cell 3D imaging, with the potential to perform large-scale morphometry of immune cell effector function states while providing compatibility with microfluidic droplet operations.

Artificial antigen-presenting cell system reveals CD28's role in modulating T cell functions during human immunodeficiency virus infection

T cell immune dysfunction is a prominent feature of chronic HIV infection. To evaluate non-specific dysfunction, a method involving both generic activation and T cell receptor (TCR) stimulation is necessary. We created a tunable artificial antigen-presenting cell (aAPC) system. This system consists of lipid bilayers on cytometry-compatible silica microbeads (5 μm). When only anti-CD3 is incorporated, T cell activation is limited. Introducing anti-CD28 agonists significantly elevates the cytokine expression and upregulation of activation-induced markers. CD28 co-stimulation modulates the response profile, preferentially promoting IL-2 expression relative to other cytokines. aAPCs-stimulated CD4+ and CD8+ T cells from untreated HIV-infected individuals exhibit altered effector functions and diminished CD28 dependence. These functions are skewed toward TNFα, IFNγ and CD107a, with reduced IL-2. Antiretroviral therapy partially normalizes this distorted profile in CD4+ T cells, but not in CD8+ T cells. Our findings show T cell intrinsic biases that may contribute to persistent systemic T cell dysfunction associated with HIV pathogenesis.

Engineering Functional Particles to Modulate T Cell Responses

T cells play a critical role in adaptive immune responses. They work with other immune cells such as B cells to protect our bodies when the first line of defense, the innate immune system, is overcome by certain infectious diseases or cancers. Studying and regulating the responses of T cells, such as activation, proliferation, and differentiation, helps us understand not only their behavior in vivo but also their translation and application in the field of immunotherapy, such as adoptive T cell therapy and immune checkpoint therapy, the situations in which T cells cannot fight cancer alone and require external engineering regulation to help them. Nano- to micrometer-sized particulate biomaterials have achieved great progress in the assistance of T cell-based immunomodulation. For example, various types of microparticles decorated with T cell recognition and activation signals to mimic native antigen-presenting cells have shown successful ex vivo expansion of primary T cells and have been approved for clinical use in adoptive T cell therapy. Functional particles can also serve as vehicles for transporting cargos including small molecule drugs, cytokines, and antibodies. Especially for cargos with limited bioavailability and high repeat-dose toxicity, systemic administration in their free form is difficult. By using particle-assisted systems, the delivery can be tailored on demand, of which targeting and controlled release are two typical examples, ultimately aiding in the regulation of T cell responses. Furthermore, when T cells become overactive and behave in ways that contradict our expectations, such as attacking our own cells or innocuous foreign molecules, this can lead to a breakdown of immune tolerance. In such cases, particles to help reprogram those overactive T cells or suppress their activity are appreciated in vivo. The urgent need to introduce immune stimulation into the treatment of cancers, infectious diseases, and autoimmune diseases has driven recent advances in the engineering of functional particulate biomaterials that regulate T cell responses. In this Account, we will first cover a brief overview of the process of T cell-based immunomodulation from principle to development. It then outlines critical points in the design of functional particle platforms, including materials, size, morphology, surface engineering, and delivery of cargos, to modulate the features of T cells, and introduces selected work from our and other research groups with a focus on three major therapeutic applications: adoptive T cell therapy, immune checkpoint therapy, and immune tolerance restoration. Current challenges and future opportunities are also discussed.

A general pHLA-CD80 scaffold fusion protein to promote efficient antigen-specific T cell-based immunotherapy

Inadequate antigen-specific T cells activation hampers immunotherapy due to complex antigen presentation. In addition, therapeutic in vivo T cell expansion is constrained by slow expansion rates and limited functionality. Herein, we introduce a model fusion protein termed antigen-presenting cell-mimic fusion protein (APC-mimic), designed to greatly mimicking the natural antigen presentation pattern of antigen-presenting cells and directly expand T cells both in vitro and in vivo. The APC-mimic comprises the cognate peptide-human leukocyte antigen (pHLA) complex and the co-stimulatory marker CD80, which are natural ligands on APCs. Following a single stimulation, APC-mimic leads to an approximately 400-fold increase in the polyclonal expansion of antigen-specific T cells compared with the untreated group in vitro without the requirement for specialized antigen-presenting cells. Through the combination of single-cell TCR sequencing (scTCR-seq) and single-cell RNA sequencing (scRNA-seq), we identify an approximately 600-fold monoclonal expansion clonotype among these polyclonal clonotypes. It also exhibits suitability for in vivo applications confirmed in the OT-1 mouse model. Furthermore, T cells expanded by APC-mimic effectively inhibits tumor growth in adoptive cell transfer (ACT) murine models. These findings pave the way for the versatile APC-mimic platform for personalized therapeutics, enabling direct expansion of polyfunctional antigen-specific T cell subsets in vitro and in vivo.

Engineering potent chimeric antigen receptor T cells by programming signaling during T-cell activation

Programming cell signaling during T-cell activation represents a simple strategy for improving the potency of therapeutic T-cell products. Stim-R technology (Lyell Immunopharma) is a customizable, degradable synthetic cell biomimetic that emulates physiologic, cell-like presentation of signal molecules to control T-cell activation. A breadth of Stim-R formulations with different anti-CD3/anti-CD28 (αCD3/αCD28) antibody densities and stoichiometries were screened for their effects on multiple metrics of T-cell function. We identified an optimized formulation that produced receptor tyrosine kinase-like orphan receptor 1 (ROR1)-targeted chimeric antigen receptor (CAR) T cells with enhanced persistence and polyfunctionality in vitro, as assessed in repeat-stimulation assays, compared with a benchmark product generated using a conventional T-cell-activating reagent. In transcriptomic analyses, CAR T cells activated with Stim-R technology showed downregulation of exhaustion-associated gene sets and retained a unique subset of stem-like cells with effector-associated gene signatures following repeated exposure to tumor cells. Compared with the benchmark product, CAR T cells activated using the optimized Stim-R technology formulation exhibited higher peak expansion, prolonged persistence, and improved tumor control in a solid tumor xenograft model. Enhancing T-cell products with Stim-R technology during T-cell activation may help improve therapeutic efficacy against solid tumors.

Development of a highly sensitive platform for protein-protein interaction detection and regulation of T cell function

We developed a highly sensitive assay for detecting protein-protein interaction using chimeric receptors comprising two molecules of interest in the extracellular domain and interferon alpha and beta receptor subunit 1 or 2 (IFNAR1/2) in the intracellular domain. This intracellular IFNAR1/2 reconstitution system (IFNARRS) proved markedly more sensitive than the NanoBiT system, currently considered one of the best detection systems for protein interaction. Employing chimeric receptors with extracellular domains from the IFNγ or IL-2 receptor and the intracellular domains of IFNAR1/2, the IFNARRS system effectively identifies low IFNγ or IL-2 levels. Cells stably expressing these chimeric receptors responded to IFNγ secreted by activated T cells following various stimuli, including a specific peptide-antigen. The activation signals were further enhanced by the expression of relevant genes, such as costimulators, via IFN-stimulated response elements in the promoters. Besides IFNγ or IL-2, the IFNARRS system demonstrated the capability to detect other cytokines by using the corresponding extracellular domains from these target cytokine receptors.

Surface chemical modification of poly(dimethylsiloxane) for stabilizing antibody immobilization and T cell cultures

Advances in cell immunotherapy underscore the need for effective methods to produce large populations of effector T cells, driving growing interest in T-cell bioprocessing and immunoengineering. Research suggests that T cells demonstrate enhanced expansion and differentiation on soft matrices in contrast to rigid ones. Nevertheless, the influence of antibody conjugation chemistry on these processes remains largely unexplored. In this study, we examined the effect of antibody conjugation chemistry on T cell activation, expansion and differentiation using a soft and biocompatible polydimethylsiloxane (PDMS) platform. We rigorously evaluated three distinct immobilization methods, beginning with the use of amino-silane (PDMS-NH2-Ab), followed by glutaraldehyde (PDMS-CHO-Ab) or succinic acid anhydride (PDMS-COOH-Ab) activation, in addition to the conventional physical adsorption (PDMS-Ab). By employing both stable amide bonds and reducible Schiff bases, antibody conjugation significantly enhanced antibody loading and density compared to physical adsorption. Furthermore, we discovered that the PDMS-COOH-Ab surface significantly promoted IL-2 secretion, CD69 expression, and T cell expansion compared to the other groups. Moreover, we observed that both PDMS-COOH-Ab and PDMS-NH2-Ab surfaces exhibited a tendency to induce the differentiation of naïve CD4+ T cells into Th1 cells, whereas the PDMS-Ab surface elicited a Th2-biased immunological response. These findings highlight the importance of antibody conjugation chemistry in the design and development of T cell culture biomaterials. They also indicate that PDMS holds promise as a material for constructing culture platforms to modulate T cell activation, proliferation, and differentiation.

In vitro encapsulation and expansion of T and CAR-T cells using 3D synthetic thermo-responsive matrices

Suspension cell culture and rigid commercial substrates are the most common methods to clinically manufacture therapeutic CAR-T cells ex vivo. However, suspension culture and nano/micro-scale commercial substrates poorly mimic the microenvironment where T cells naturally develop, leading to profound impacts on cell proliferation and phenotype. To overcome this major challenge, macro-scale substrates can be used to emulate that environment with higher precision. This work employed a biocompatible thermo-responsive material with tailored mechanical properties as a potential synthetic macro-scale scaffold to support T cell encapsulation and culture. Cell viability, expansion, and phenotype changes were assessed to study the effect of two thermo-responsive hydrogel materials with stiffnesses of 0.5 and 17 kPa. Encapsulated Pan-T and CAR-T cells were able to grow and physically behave similar to the suspension control. Furthermore, matrix stiffness influenced T cell behavior. In the softer polymer, T cells had higher activation, differentiation, and maturation after encapsulation obtaining significant cell numbers. Even when terpolymer encapsulation affected the CAR-T cell viability and expansion, CAR T cells expressed favorable phenotypical profiles, which was supported with cytokines and lactate production. These results confirmed the biocompatibility of the thermo-responsive hydrogels and their feasibility as a promising 3D macro-scale scaffold for in vitro T cell expansion that could potentially be used for cell manufacturing process.

Particle-Based Artificial Antigen-Presenting Cell Systems for T Cell Activation in Adoptive T Cell Therapy

T cell-based adoptive cell therapy (ACT) has emerged as a promising treatment for various diseases, particularly cancers. Unlike other immunotherapy modalities, ACT involves directly transferring engineered T cells into patients to eradicate diseased cells; hence, it necessitates methods for effectively activating and expanding T cells in vitro. Artificial antigen-presenting cells (aAPCs) have been widely developed based on biomaterials, particularly micro- and nanoparticles, and functionalized with T cell stimulatory antibodies to closely mimic the natural T cell-APC interactions. Due to their vast clinical utility, aAPCs have been employed as an off-the-shelf technology for T cell activation in FDA-approved ACTs, and the development of aAPCs is constantly advancing with the emergence of aAPCs with more sophisticated designs and additional functionalities. Here, we review the recent advancements in particle-based aAPCs for T cell activation in ACTs. Following a brief introduction, we first describe the manufacturing processes of ACT products. Next, the design and synthetic strategies for micro- and nanoparticle-based aAPCs are discussed separately to emphasize their features, advantages, and limitations. Then, the impact of design parameters of aAPCs, such as size, shape, ligand density/mobility, and stiffness, on their functionality and biomedical performance is explored to provide deeper insights into the design concepts and principles for more efficient and safer aAPCs. The review concludes by discussing current challenges and proposing future perspectives for the development of more advanced aAPCs.

Microfluidic-based preparation of artificial antigen-presenting gel droplets for integrated and minimalistic adoptive cell therapy strategies

Adoptive T-cell transfer for cancer therapy is limited by the inefficiency ofin vitroT-cell expansion and the ability ofin vivoT-cells to infiltrate tumors. The construction of multifunctional artificial antigen-presenting cells is a promising but challenging approach to achieve this goal. In this study, a multifunctional artificial antigen-presenting gel droplet (AAPGD) was designed. Its surface provides regulated T-cell receptor (TCR) stimulation and co-stimulation signals and is capable of slow release of mitogenic cytokines and collagen mimetic peptide. The highly uniform AAPGD are generated by a facile method based on standard droplet microfluidic devices. The results of the study indicate that, T-cell proliferatedin vitroutilizing AAPGD have a fast rate and high activity. AAPGD increased the proportion ofin vitroproliferating T cells low differentiation and specificity. The starting number of AAPGDs and the quality ratio of TCR-stimulated and co-stimulated signals on the surface have a large impact on the rapid proliferation of low-differentiated T cellsin vitro. During reinfusion therapy, AAPGD also enhanced T-cell infiltration into the tumor site. In experiments using AAPGD for adoptive T cell therapy in melanoma mice, tumor growth was inhibited, eliciting a potent cytotoxic T-lymphocyte immune response and improving mouse survival. In conclusion, AAPGD promotes rapid low-differentiation proliferation of T cellsin vitroand enhances T cell infiltration of tumorsin vivo. It simplifies the preparation steps of adoptive cell therapy, improves the therapeutic effect, and provides a new pathway for overdosing T cells to treat solid tumors.

Nanofibrous MultiDomain Peptide Hydrogels Provide T Cells a 3D, Cytocompatible Environment for Cell Expansion and Antigen-Specific Killing

T cells have the ability to recognize and kill specific target cells, giving therapies based on their potential for treating infection, diabetes, cancer, and other diseases. However, the advancement of T cell-based treatments has been hindered by difficulties in their ex vivo activation and expansion, the number of cells required for sustained in vivo levels, and preferential localization following systemic delivery. Biomaterials may help to overcome many of these challenges by providing a combined means of proliferation, antigen presentation, and cell localization upon delivery. In this work, we studied self-assembling Multidomain Peptides (MDPs) as scaffolds for T cell culture, activation, and expansion. We evaluated the effect of different MDP chemistries on their biocompatibility with T cells and the maintenance of antigen specificity for T cells cultured in the hydrogels. We also examined the potential application of MDPs as scaffolds for T cell activation and expansion and the effect of MDP encapsulation on T cell phenotype. We found high cell viability when T cells were encapsulated in noncationic MDPs, O5 and D2, and superior retention of antigen specificity and tumor-reactivity were preserved in the anionic MDP, D2. Maintenance of antigen recognition by T cells in D2 hydrogels was confirmed by quantifying immune synapses of T Cells engaged with antigen-presenting cancer cells. When 3D cultured in anionic MDP D2 coloaded with anti-CD3, anti-CD28, IL2, IL7, and IL15, we observed successful T cell proliferation evidenced by upregulation of CD27 and CD107a. This study is the first to investigate the potential of self-assembling peptide-based hydrogels as 3D scaffolds for human T cell applications and demonstrates that MDP hydrogels are a viable platform for enabling T cell in vitro activation, expansion, and maintenance of antigen specificity and therefore a promising tool for future T cell-based therapies.

Mechanical forces amplify TCR mechanotransduction in T cell activation and function

Adoptive T cell immunotherapies, including engineered T cell receptor (eTCR) and chimeric antigen receptor (CAR) T cell immunotherapies, have shown efficacy in treating a subset of hematologic malignancies, exhibit promise in solid tumors, and have many other potential applications, such as in fibrosis, autoimmunity, and regenerative medicine. While immunoengineering has focused on designing biomaterials to present biochemical cues to manipulate T cells ex vivo and in vivo, mechanical cues that regulate their biology have been largely underappreciated. This review highlights the contributions of mechanical force to several receptor-ligand interactions critical to T cell function, with central focus on the TCR-peptide-loaded major histocompatibility complex (pMHC). We then emphasize the role of mechanical forces in (i) allosteric strengthening of the TCR-pMHC interaction in amplifying ligand discrimination during T cell antigen recognition prior to activation and (ii) T cell interactions with the extracellular matrix. We then describe approaches to design eTCRs, CARs, and biomaterials to exploit TCR mechanosensitivity in order to potentiate T cell manufacturing and function in adoptive T cell immunotherapy.

Nanoparticle-mediated cancer cell therapy: basic science to clinical applications

Every sixth person in the world dies due to cancer, making it the second leading severe cause of death after cardiovascular diseases. According to WHO, cancer claimed nearly 10 million deaths in 2020. The most common types of cancers reported have been breast (lung, colon and rectum, prostate cases), skin (non-melanoma) and stomach. In addition to surgery, the most widely used traditional types of anti-cancer treatment are radio- and chemotherapy. However, these do not distinguish between normal and malignant cells. Additional treatment methods have evolved over time for early detection and targeted therapy of cancer. However, each method has its limitations and the associated treatment costs are quite high with adverse effects on the quality of life of patients. Use of individual atoms or a cluster of atoms (nanoparticles) can cause a paradigm shift by virtue of providing point of sight sensing and diagnosis of cancer. Nanoparticles (1-100 nm in size) are 1000 times smaller in size than the human cell and endowed with safer relocation capability to attack mechanically and chemically at a precise location which is one avenue that can be used to destroy cancer cells precisely. This review summarises the extant understanding and the work done in this area to pave the way for physicians to accelerate the use of hybrid mode of treatments by leveraging the use of various nanoparticles.

Targeting the tumor microenvironment: Potential strategy for cancer therapeutics

Cellular and stromal components including tumor cells, immune cells, mesenchymal cells, cancer-linked fibroblasts, and extracellular matrix, constituent tumor microenvironment (TME). TME plays a crucial role in reprogramming tumor initiation, uncontrolled proliferation, invasion and metastasis as well as response to therapeutic modalities. In recent years targeting the TME has developed as a potential strategy for treatment of cancer because of its life-threatening functions in restricting tumor development and modulating responses to standard-of-care medicines. Cold atmospheric plasma, oncolytic viral therapy, bacterial therapy, nano-vaccine, and repurposed pharmaceuticals with combination therapy, antiangiogenic drugs, and immunotherapies are among the most effective therapies directed by TME that have either been clinically authorized or are currently being studied. This article discusses above-mentioned therapies in light of targeting TME. We also cover problems related to the TME-targeted therapies, as well as future insights and practical uses in this rapidly growing field.

T cell-responsive macroporous hydrogels for in situ T cell expansion and enhanced antitumor efficacy

Adoptive T cell therapy has demonstrated great promise for treating cancer and other diseases. While extensive effort has been made to improve ex vivo expansion of T cells, strategies for maintaining the proliferation and function of T cells post adoptive transfer are still lacking. Here we report an injectable T cell-responsive macroporous hydrogel that enables in situ activation and expansion of T cells. The macroporous gel is composed of a polymeric network with dispersed macropores (∼150 μm) that are large enough to home T cells. In the presence of T cells that can gradually disrupt the gel network surrounding the macropores, activation cues can be gradually released for in situ activation and expansion of T cells. This T cell-responsive macroporous gel enables expansion of effector T cells in vivo, is stable over weeks upon subcutaneous injection, and results in enhanced CD8+ T cell response and antitumor efficacy. We further show that the T cell-responsive macroporous gel could achieve comparable antitumor efficacy to conventional T cell therapy with a much lower cell dose. This injectable, T cell-responsive macroporous gel provides a platform for in vivo expansion of engineered T cells in a controlled manner, for timely and effective treatment of diseases.

Enhancing CAR-T cell functionality in a patient-specific manner

Patient responses to autologous CD19 chimeric antigen receptor (CAR) T-cell therapies are limited by insufficient and inconsistent cellular functionality. Here, we show that controlling the precise level of stimulation during T-cell activation to accommodate individual differences in the donor cells will dictate the functional attributes of CAR-T cell products. The functionality of CAR-T cell products, consisting of a diverse set of blood samples derived from healthy donors, acute lymphoblastic leukemia (ALL), and chronic lymphocytic lymphoma (CLL) patient samples, representing a range of patient health status, is tested upon culturing on artificial antigen-presenting cell scaffolds to deliver T-cell stimulatory ligands (anti-CD3/anti-CD28) at highly defined densities. A clear relationship is observed between the dose of stimulation, the phenotype of the T-cell blood sample prior to T-cell activation, and the functionality of the resulting CAR-T cell products. We present a model, based on this dataset, that predicts the precise stimulation needed to manufacture a desired CAR-T cell product, given the input T-cell attributes in the initial blood sample. These findings demonstrate a simple approach to enhance CAR-T functionality by personalizing the level of stimulation during T-cell activation to enable flexible manufacturing of more consistent and potent CAR-T cells.

Extracellular Vesicles Expressing CD19 Antigen Improve Expansion and Efficacy of CD19-Targeted CAR-T Cells

Background

CAR-T cell therapy is effective in the treatment of certain hematological malignancies, and the expansion and functional persistence of CAR-T cells in vivo are crucial to clinical efficacy. The aim of this study was to investigate the potential of extracellular vesicles (EVs) modified with the CAR antigen to promote the efficacy of CAR-T cells in vivo.

Methods

We generated HEK293T-derived EVs to present the CD19 antigen as the CAR target. In vitro, EVs expressing CD19 antigen (CD19 EVs) were co-incubated with anti-CD19 CAR-T cells. Then, proliferation, cytokine secretion, CD107a expression, tumor killing, subsets, and immune checkpoint expression were measured to assess CAR-T cell function. After infusion of CD19 EVs pretreated CAR-T cells into a lymphoma xenograft mouse model, flow cytometry and digital PCR were used to measure the expansion of CAR-T cells, and tumor volumes were continuously monitored to assess the anti-tumor efficacy of CAR-T cells in vivo. Another mouse model was created to investigate the effect of in vivo injection of CD19 EVs on the functional persistence of CAR-T cells, and safety was determined by histopathology of the main organs.

Results

CD19 EVs activated CAR-T cells in an antigen-specific and dose-dependent manner and promoted the selective expansion and cytokine secretion of co-cultured CAR-T cells. Specifically, CD19 EVs preferably increased the expansion of the CAR-T subpopulation with a high surface CD19-CAR density and consequently enhanced the anti-tumor activity of CAR-T cells. Futhermore, CD19-EVs-primed CAR-T cells achieved superior proliferation and anti-tumor effects in a mouse model with lymphoma xenograft. In vivo administration of CD19 EVs promoted the functional persistence of CAR-T cells in the xenograft mouse model.

Conclusion

Our findings indicate that antigen-expressing EVs can be utilized as a boost to improve CAR-T cell efficacy in vitro and in vivo.

Detection of Low-Frequency Epitope-Specific T Cells in Blood of Healthy Individuals according to an Optimized In Vitro Amplification System

Detection and amplification of epitope-specific T cells hold great promise for diagnosis and therapy of cancer patients. Currently, measurement and retrieval of epitope-specific T cells is hampered by limited availability of patients' biomaterials and lack of sensitive and easy-to-implement T cell priming and expansion. We have developed an in vitro T cell amplification system starting from healthy donor blood and tested different subsets and ratios of autologous T cells and APCs as well as the resting period between amplification cycles. We demonstrated in 10 different donors significantly enhanced frequency of T cells specific for MelanA/HLA-A2, which relied on coculturing of naive T cells and CD11c+ dendritic cells in a 1:1 ratio followed by three weekly amplification cycles using the effluent of the naive T cell sort as APCs, a 24-h rest period prior to every reamplification cycle, and IFN-γ production as a readout for epitope-specific T cells. Using this system, MelanA/HLA-A2-specific T cells were enriched by 200-fold, measuring up to 20-60% of all T cells. We extended this system to enrich NY-ESO-1/HLA-A2- and BMLF-1/HLA-A2-specific T cells, examples of a cancer germline Ag and an oncoviral Ag differing in their ability to bind to HLA-A2 and the presence of specific T cells in the naive and, in case of BMLF-1, also the Ag-experienced repertoire. Collectively, we have developed a sensitive and easy-to-implement in vitro T cell amplification method to enrich epitope-specific T cells that is expected to facilitate research and clinical utility regarding T cell diagnosis and treatments.

Three-dimensional (3D) scaffolds as powerful weapons for tumor immunotherapy

Though increasing understanding and remarkable clinical successes have been made, enormous challenges remain to be solved in the field of cancer immunotherapy. In this context, biomaterial-based immunomodulatory strategies are being developed to boost antitumor immunity. For the local immunotherapy, macroscale biomaterial scaffolds with 3D network structures show great superiority in the following aspects: facilitating the encapsulation, localized delivery, and controlled release of immunotherapeutic agents and even immunocytes for more efficient immunomodulation. The concentrating immunomodulation in situ could minimize systemic toxicities, but still exert abscopal effects to harness the power of overall anticancer immune response for eradicating malignancy. To promote such promising immunotherapies, the design requirements of macroscale 3D scaffolds should comprehensively consider their physicochemical and biological properties, such as porosity, stiffness, surface modification, cargo release kinetics, biocompatibility, biodegradability, and delivery modes. To date, increasing studies have focused on the relationships between these parameters and the biosystems which will guide/assist the 3D biomaterial scaffolds to achieve the desired immunotherapeutic outcomes. In this review, by highlighting some recent achievements, we summarized the latest advances in the development of various 3D scaffolds as niches for cancer immunotherapy. We also discussed opportunities, challenges, current trends, and future perspectives in 3D macroscale biomaterial scaffold-assisted local treatment strategies. More importantly, this review put more efforts to illustrate how the 3D biomaterial systems affect to modulate antitumor immune activities, where we discussed how significant the roles and behaviours of 3D macroscale scaffolds towards in situ cancer immunotherapy in order to direct the design of 3D immunotherapeutic.

Optimization of Culture Media for Ex vivo T-Cell Expansion for Adoptive T-Cell Therapy

BACKGROUND

Adoptive T-cell therapy is a promising treatment strategy for cancer immunotherapy. The ability of immunotherapy based on the adoptive cell transfer of genetically modified T cells to generate powerful clinical responses has been highlighted by recent clinical success. Techniques which are used to expand large numbers of T cells from different sources are critical in adoptive cell therapy. In this study, we evaluated the expansion, proliferation, activation of T lymphocytes, in the presence of various concentrations of interleukin-2, phytohemagglutinin (PHA), and insulin.

MATERIALS AND METHODS

The effect of different supplemented culture media on T cell expansion was evaluated using MTT assay. The expression level of the Ki-67 proliferation marker was evaluated by real-time polymerase chain reaction. In addition, flow cytometry analysis was performed to access T cell subpopulations.

RESULTS

Our results showed that supplemented culture media with an optimized concentration of PHA and interleukin-2 increased total fold expansion of T cells up to 500-fold with approximately 90% cell viability over 7 days. The quantitative assessment of Ki-67 in expanded T cells showed a significant elevation of this proliferation marker. Flow cytometry was also used to assess the proportion of CD4+ and CD8+ cells, and the main expanded population was CD3+ CD8+ cells.

CONCLUSIONS

Based on these findings, we introduced a low-cost and rapid method to support the efficient expansion of T cells for adoptive cell therapy and other in vivo experiments.

Engineered Bacterial Outer Membrane Vesicles as Controllable Two-Way Adaptors to Activate Macrophage Phagocytosis for Improved Tumor Immunotherapy

The most immune cells infiltrating tumor microenvironment (TME), tumor-associated macrophages (TAMs) closely resemble immunosuppressive M2-polarized macrophages. Moreover, tumor cells exhibit high expression of CD47 "don't eat me" signal, which obstructs macrophage phagocytosis. The precise and efficient activation of TAMs is a promising approach to tumor immunotherapy; however, re-education of macrophages remains a challenge. Bacteria-derived outer membrane vesicles (OMVs) are highly immunogenic nanovesicles that can robustly stimulate macrophages. Here, an OMV-based controllable two-way adaptor is reported, in which a CD47 nanobody (CD47nb) is fused onto OMV surface (OMV-CD47nb), with the outer surface coated with a polyethylene glycol (PEG) layer containing diselenide bonds (PEG/Se) to form PEG/Se@OMV-CD47nb. The PEG/Se layer modification not only mitigates the immunogenicity of OMV-CD47nb, thereby remarkedly increasing the dose that can be administered safely through intravenous injection, but also equips the formulation with radiation-triggered controlled release of OMV-CD47nb. Application of radiation to tumors in mice injected with the nanoformulation results in remodeling of TME. As two-way adaptors, OMV-CD47nb activates TAM phagocytosis of tumor cells via multiple pathways, including induction of M1 polarization and blockade of "don't eat me" signal. Moreover, this activation of TAMs results in the stimulation of T cell-mediated antitumor immunity through effective antigen presentation.

Targeting tumor extracellular matrix activates the tumor-draining lymph nodes

Disruption of the tumor extracellular matrix (ECM) may alter immune cell infiltration into the tumor and antitumor T cell priming in the tumor-draining lymph nodes (tdLNs). Here, we explore how intratumoral enzyme treatment (ET) of B16 melanoma tumors with ECM-depleting enzyme hyaluronidase alters adaptive and innate immune populations, including T cells, DCs, and macrophages, in the tumors and tdLNs. ET increased CD103⁺ DC abundance in the tdLNs, as well as antigen presentation of a model tumor antigen ovalbumin (OVA), eliciting local OVA-specific CD8⁺ T cell responses. Delivered in combination with a distant cryogel-based cancer vaccine, ET increased the systemic antigen-specific CD8⁺ T cell response. By enhancing activity within the tdLN, ET may broadly support immunotherapies in generating tumor-specific immunity.

Emerging vaccine nanotechnology: From defense against infection to sniping cancer

Looking retrospectively at the development of humanity, vaccination is an unprecedented medical landmark that saves lives by harnessing the human immune system. During the ongoing coronavirus disease 2019 (COVID-19) pandemic, vaccination is still the most effective defense modality. The successful clinical application of the lipid nanoparticle-based Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines highlights promising future of nanotechnology in vaccine development. Compared with conventional vaccines, nanovaccines are supposed to have advantages in lymph node accumulation, antigen assembly, and antigen presentation; they also have, unique pathogen biomimicry properties because of well-organized combination of multiple immune factors. Beyond infectious diseases, vaccine nanotechnology also exhibits considerable potential for cancer treatment. The ultimate goal of cancer vaccines is to fully mobilize the potency of the immune system as a living therapeutic to recognize tumor antigens and eliminate tumor cells, and nanotechnologies have the requisite properties to realize this goal. In this review, we summarize the recent advances in vaccine nanotechnology from infectious disease prevention to cancer immunotherapy and highlight the different types of materials, mechanisms, administration methods, as well as future perspectives.

Myeloid Immune Cells CARrying a New Weapon Against Cancer

Chimeric antigen receptor (CAR) engineering for T cells and natural killer cells (NK) are now under clinical evaluation for the treatment of hematologic cancers. Although encouraging clinical results have been reported for hematologic diseases, pre-clinical studies in solid tumors have failed to prove the same effectiveness. Thus, there is a growing interest of the scientific community to find other immune cell candidate to express CAR for the treatment of solid tumors and other diseases. Mononuclear phagocytes may be the most adapted group of cells with potential to overcome the dense barrier imposed by solid tumors. In addition, intrinsic features of these cells, such as migration, phagocytic capability, release of soluble factors and adaptive immunity activation, could be further explored along with gene therapy approaches. Here, we discuss the elements that constitute the tumor microenvironment, the features and advantages of these cell subtypes and the latest studies using CAR-myeloid immune cells in solid tumor models.

Core-shell microparticles: From rational engineering to diverse applications

Core-shell microparticles, composed of solid, liquid, or gas bubbles surrounded by a protective shell, are gaining considerable attention as intelligent and versatile carriers that show great potential in biomedical fields. In this review, an overview is given of recent developments in design and applications of biodegradable core-shell systems. Several emerging methodologies including self-assembly, gas-shearing, and coaxial electrospray are discussed and microfluidics technology is emphasized in detail. Furthermore, the characteristics of core-shell microparticles in artificial cells, drug release and cell culture applications are discussed and the superiority of these advanced multi-core microparticles for the generation of artificial cells is highlighted. Finally, the respective developing orientations and limitations inherent to these systems are addressed. It is hoped that this review can inspire researchers to propel the development of this field with new ideas.

Advances in plant-derived natural products for antitumor immunotherapy

In recent years, immunotherapy has emerged as a novel antitumor strategy in addition to traditional surgery, radiotherapy and chemotherapy. It uniquely focuses on immune cells and immunomodulators in the tumor microenvironment and helps eliminate tumors at the root by rebuilding the immune system. Despite remarkable breakthroughs, cancer immunotherapy still faces many challenges: lack of predictable and prognostic biomarkers, adverse side effects, acquired treatment resistance, high costs, etc. Therefore, more efficacious and efficient, safer and cheaper antitumor immunomodulatory drugs have become an urgent requirement. For decades, plant-derived natural products obtained from land and sea have provided the most important source for the development of antitumor drugs. Currently, more attention is being paid to the discovery of potential cancer immunotherapy modulators from plant-derived natural products, such as polysaccharides, phenols, terpenoids, quinones and alkaloids. Some of these agents have outstanding advantages of multitargeting and low side effects and low cost compared to conventional immunotherapeutic agents. We intend to summarize the progress of comprehensive research on these plant-derived natural products and their derivatives and discuss their possible mechanisms in regulating the immune system and their efficacy as monotherapies or in combination with regular chemotherapeutic agents.

Antigen-Specific Stimulation and Expansion of CAR-T Cells Using Membrane Vesicles as Target Cell Surrogates

Development of CAR-T therapy led to immediate success in the treatment of B cell leukemia. Manufacturing of therapy-competent functional CAR-T cells needs robust protocols for ex vivo/in vitro expansion of modified T-cells. This step is challenging, especially if non-viral low-efficiency delivery protocols are used to generate CAR-T cells. Modern protocols for CAR-T cell expansion are imperfect since non-specific stimulation results in rapid outgrowth of CAR-negative T cells, and removal of feeder cells from mixed cultures necessitates additional purification steps. To develop a specific and improved protocol for CAR-T cell expansion, cell-derived membrane vesicles are taken advantage of, and the simple structural demands of the CAR-antigen interaction. This novel approach is to make antigenic microcytospheres from common cell lines stably expressing surface-bound CAR antigens, and then use them for stimulation and expansion of CAR-T cells. The data presented in this article clearly demonstrate that this protocol produced antigen-specific vesicles with the capacity to induce stronger stimulation, proliferation, and functional activity of CAR-T cells than is possible with existing protocols. It is predicted that this new methodology will significantly advance the ability to obtain improved populations of functional CAR-T cells for therapy.

Keeping Myeloma in Check: The Past, Present and Future of Immunotherapy in Multiple Myeloma

Multiple myeloma is an incurable disease of malignant plasma cells and an ideal target for modern immune therapy. The unique plasma cell biology maintained in multiple myeloma, coupled with its hematological nature and unique bone marrow microenvironment, provide an opportunity to design specifically targeted immunotherapies that selectively kill transformed cells with limited on-target off-tumor effects. Broadly defined, immune therapy is the utilization of the immune system and immune agents to treat a disease. In the context of multiple myeloma, immune therapy can be subdivided into four main categories: immune modulatory imide drugs, targeted antibodies, adoptive cell transfer therapies, and vaccines. In recent years, advances in all four of these categories have led to improved therapies with enhanced antitumor activity and specificity. In IMiDs, modified chemical structures have been developed that improve drug potency while reducing dose limiting side effects. Targeted antibody therapies have resulted from the development of new selectively expressed targets as well as the development of antibody drug conjugates and bispecific antibodies. Adoptive cell therapies, particularly CAR-T therapies, have been enhanced through improvements in the manufacturing process, as well as through the development of CAR constructs that enhance CAR-T activation and provide protection from a suppressive immune microenvironment. This review will first cover in-class breakthrough therapies for each of these categories, as well as therapies currently utilized in the clinic. Additionally, this review will explore up and coming therapeutics in the preclinical and clinical trial stage.

Engineering stromal heterogeneity in cancer

Based on our exponentially increasing knowledge of stromal heterogeneity from advances in single-cell technologies, the notion that stromal cell types exist as a spectrum of unique subpopulations that have specific functions and spatial distributions in the tumor microenvironment has significant impact on tumor modeling for drug development and personalized drug testing. In this Review, we discuss the importance of incorporating stromal heterogeneity and tumor architecture, and propose an overall approach to guide the reconstruction of stromal heterogeneity in vitro for tumor modeling. These next-generation tumor models may support the development of more precise drugs targeting specific stromal cell subpopulations, as well as enable improved recapitulation of patient tumors in vitro for personalized drug testing.

Engineering microenvironments for manufacturing therapeutic cells

There are a growing number of globally approved products and clinical trials utilizing autologous and allogeneic therapeutic cells for applications in regenerative medicine and immunotherapies. However, there is a need to develop rapid and cost-effective methods for manufacturing therapeutically effective cells. Furthermore, the resulting manufactured cells may exhibit heterogeneities that result in mixed therapeutic outcomes. Engineering approaches that can provide distinct microenvironmental cues to these cells may be able to enhance the growth and characterization of these cell products. This mini-review describes strategies to potentially enhance the expansion of therapeutic cells with biomaterials and bioreactors, as well as to characterize the cell products with microphysiological systems. These systems can provide distinct cues to maintain the quality attributes of the cells and evaluate their function in physiologically relevant conditions.

Chemically Engineered Immune Cell-Derived Microrobots and Biomimetic Nanoparticles: Emerging Biodiagnostic and Therapeutic Tools

Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.

Objectives, benefits and challenges of bioreactor systems for the clinical-scale expansion of T lymphocyte cells

Cell therapies based on T cell have gathered interest over the last decades for treatment of cancers, becoming recently the most investigated lineage for clinical trials. Although results of adoptive cell therapies are very promising, obtaining large batches of T cell at clinical scale is still challenging nowadays. We propose here a review study focusing on how bioreactor systems could increase expansion rates of T cell culture specifically towards efficient, reliable and reproducible cell therapies. After describing the specificities of T cell culture, in particular activation, phenotypical characterization and cell density considerations, we detail the main objectives of bioreactors in this context, namely scale-up, GMP-compliance and reduced time and costs. Then, we report recent advances on the different classes of bioreactor systems commonly investigated for non-adherent cell expansion, in comparison with the current "gold standard" of T cell culture (flasks and culture bag). Results obtained with hollow fibres, G-Rex® flasks, Wave bioreactor, multiple-step bioreactors, spinner flasks as well as original homemade designs are discussed to highlight advantages and drawbacks in regards to T cells' specificities. Although there is currently no consensus on an optimal bioreactor, overall, most systems reviewed here can improve T cell culture towards faster, easier and/or cheaper protocols. They also offer strong outlooks towards automation, process control and complete closed systems, which could be mandatory developments for a massive clinical breakthrough. However, proper controls are sometimes lacking to conclude clearly on the features leading to the progresses regarding cell expansion, and the field could benefit from process engineering methods, such as quality by design, to perform multi parameters studies and face these challenges.

Engineering Nanoscale Artificial Antigen-Presenting Cells by Metabolic Dendritic Cell Labeling to Potentiate Cancer Immunotherapy

Nanoscale artificial antigen-presenting cells (aAPCs) are promising to activate T cells directly for cancer immunotherapy, while feasible and flexible strategy to develop nanoscale aAPCs remains highly desirable. Metabolic glycoengineering is used to decorate chemical tags on cells which enables bioorthogonal chemical conjugation of functional molecules. Herein, we develop a nanoscale aAPC by metabolic dendritic cell (DC) labeling to mobilize T-cell based antitumor immunity. We coat azido-labeled DC membrane on imiquimod-loaded polymeric nanoparticles and sequentially modify anti-CD3ε antibody via click chemistry. The nanoscale aAPCs perform improved distribution in lymph nodes and stimulate T cells and resident APCs. Significant inhibition of tumor inoculation and growth is observed after the vaccination, which can be further improved by combining antiprogrammed cell death receptor 1 (PD1) therapy. Our results demonstrate the promising application of metabolically labeled DCs for designing nanoscale aAPCs, which provide a simple and general strategy to potentiate cancer immunotherapy.

Biomaterials to enhance antigen-specific T cell expansion for cancer immunotherapy

T cells are often referred to as the 'guided missiles' of our immune system because of their capacity to traffic to and accumulate at sites of infection or disease, destroy infected or mutated cells with high specificity and sensitivity, initiate systemic immune responses, sterilize infections, and produce long-lasting memory. As a result, they are a common target for a range of cancer immunotherapies. However, the myriad of challenges of expanding large numbers of T cells specific to each patient's unique tumor antigens has led researchers to develop alternative, more scalable approaches. Biomaterial platforms for expansion of antigen-specific T cells offer a path forward towards broadscale translation of personalized immunotherapies by providing "off-the-shelf", yet modular approaches to customize the phenotype, function, and specificity of T cell responses. In this review, we discuss design considerations and progress made in the development of ex vivo and in vivo technologies for activating antigen-specific T cells, including artificial antigen presenting cells, T cell stimulating scaffolds, biomaterials-based vaccines, and artificial lymphoid organs. Ultimate translation of these platforms as a part of cancer immunotherapy regimens hinges on an in-depth understanding of T cell biology and cell-material interactions.

3D Culture Systems for Exploring Cancer Immunology

Simple Summary

To study any disease, researchers need convenient and relevant disease models. In cancer, the most commonly used models are two-dimensional (2D) culture models, which grow cells on hard, rigid, plastic surfaces, and mouse models. Cancer immunology is especially difficult to model because the immune system is exceedingly complex; it contains multiple types of cells, and each cell type has several subtypes and a spectrum of activation states. These many immune cell types interact with cancer cells and other components of the tumor, ultimately influencing disease outcomes. 2D culture methods fail to recapitulate these complex cellular interactions. Mouse models also suffer because the murine and human immune systems vary significantly. Three-dimensional (3D) culture systems therefore provide an alternative method to study cancer immunology and can fill the current gaps in available models. This review will describe common 3D culture models and how those models have been used to advance our understanding of cancer immunology.

Abstract

Cancer immunotherapy has revolutionized cancer treatment, spurring extensive investigation into cancer immunology and how to exploit this biology for therapeutic benefit. Current methods to investigate cancer-immune cell interactions and develop novel drug therapies rely on either two-dimensional (2D) culture systems or murine models. However, three-dimensional (3D) culture systems provide a potentially superior alternative model to both 2D and murine approaches. As opposed to 2D models, 3D models are more physiologically relevant and better replicate tumor complexities. Compared to murine models, 3D models are cheaper, faster, and can study the human immune system. In this review, we discuss the most common 3D culture systems—spheroids, organoids, and microfluidic chips—and detail how these systems have advanced our understanding of cancer immunology.

Cross talk between human regulatory T cells and antigen-presenting cells: Lessons for clinical applications

Regulatory T cells (Tregs) have a critical role in maintaining self-tolerance and immune homeostasis. There is much interest in using Tregs as a cell therapy to re-establish tolerance in conditions such as inflammatory bowel disease and type 1 diabetes, with many ongoing clinical studies testing the safety and efficacy of this approach. Manufacturing of Tregs for therapy typically involves ex vivo expansion to obtain sufficient cell numbers for infusion and comes with the risk of altering the activity of key biological processes. However, this process also offers an opportunity to tailor Treg function to maximize in vivo activity. In this review, we focus on the roles of antigen-presenting cells (APCs) in the generation and function of Tregs in humans. In addition to stimulating the development of Tregs, APCs activate Tregs and provide signals that induce specialized functional and homing marker expression. Cross talk between Tregs and APCs is a critical, often under-appreciated, aspect of Treg biology, with APCs mediating the key properties of infectious tolerance and bystander suppression. Understanding the biology of human Treg-APC interactions will reveal new ways to optimize Treg-based therapeutic approaches.

Nanoparticles as Smart Carriers for Enhanced Cancer Immunotherapy

Cancer immunotherapy has emerged as a promising strategy for the treatment of many forms of cancer by stimulating body's own immune system. This therapy not only eradicates tumor cells by inducing strong anti-tumor immune response but also prevent their recurrence. The clinical cancer immunotherapy faces some insurmountable challenges including high immune-mediated toxicity, lack of effective and targeted delivery of cancer antigens to immune cells and off-target side effects. However, nanotechnology offers some solutions to overcome those limitations, and thus can potentiate the efficacy of immunotherapy. This review focuses on the advancement of nanoparticle-mediated delivery of immunostimulating agents for efficient cancer immunotherapy. Here we have outlined the use of the immunostimulatory nanoparticles as a smart carrier for effective delivery of cancer antigens and adjuvants, type of interactions between nanoparticles and the antigen/adjuvant as well as the factors controlling the interaction between nanoparticles and the receptors on antigen presenting cells. Besides, the role of nanoparticles in targeting/activating immune cells and modulating the immunosuppressive tumor microenvironment has also been discussed extensively. Finally, we have summarized some theranostic applications of the immunomodulatory nanomaterials in treating cancers based on the earlier published reports.

Chemical Strategies to Enhance the Therapeutic Efficacy of Toll-like Receptor Agonist Based Cancer Immunotherapy

Recent developments in the fields of biomedical chemistry and immune bioengineering have enabled innovative therapeutic approaches that can enhance the efficacy, accuracy, and safety of cancer immunotherapy. Among the numerous strategies utilized in cancer immunotherapy, Toll-like receptor (TLR) agonist-based approaches have been studied for a long time since they trigger the innate immune system and generate antigen-specific T cell responses to fight against tumors. In addition to these immunostimulatory functions, TLR agonists also contribute to the reprogramming of immune suppressive tumor microenvironments. Although TLR agonists are now being intensively studied in clinical trials due to their substantial immunomodulatory properties, they still show a low therapeutic index. Nonspecific and random stimulation of various immune cells produces excess levels of proinflammatory cytokines, resulting in cytokine storms and chronic diseases. Therefore, the development of chemical strategies to enhance the therapeutic efficacy as well as the safety of TLR agonist-based immunotherapy is essential and in high demand.In this Account, we summarize and discuss recent developments in biomedical chemistry and bioengineering techniques for the immunomodulation of TLR agonists that have addressed the limitations in current cancer immunotherapy. Immunomodulation of TLR agonists can be classified into two different approaches: (1) molecular modulation via chemical structure modification and (2) macroscopic modulation via an engineered drug delivery system. In molecular modulation, based on prodrug and antedrug principles, activity is modulated (active or inactive) through immolative chemical linkers that can respond to extrinsic or intrinsic biological stimulation and the plasmatic environment, respectively. To increase the effectiveness of TLR agonists as immunostimulatory agents, researchers have conjugated TLR agonists with other immunotherapeutic moieties (antigen, antibody, other TLR agonist, etc.). For macroscopic modulation, bioengineering of delivery carriers differing in size or with albumin hitchhiking moieties has been utilized to increase the efficiency of the targeting of these carriers to secondary lymphoid organs (lymph nodes (LNs) and spleen). The conjugation of specific targeting ligands and incorporation of stimulus-triggering moieties can promote the delivery of TLR agonists into specific cells or intracellular compartments. Implantable porous scaffolds for specific immune cell recruitment and in situ depot-forming gel systems for controlled release of immunomodulatory drugs can increase the therapeutic efficacy of TLR agonists while reducing systemic toxicity. Taken together, these findings show that well-designed and precisely controlled chemical strategies for the immunomodulation of TLR agonists at both the molecular and macroscopic levels are expected to play key roles in improving the therapeutic efficacy of cancer immunotherapy while minimizing immune-related toxicity.