Chimeric antigen receptor (CAR)-engineered T cells redirected against hepatitis C virus (HCV) E2 glycoprotein

CAR-T Therapy Beyond B-Cell Hematological Malignancies

Despite the advances of CAR-T cells in certain hematological malignancies, mostly from B-cell derivations such as non-Hodgkin lymphomas, acute lymphoblastic leukemia and multiple myeloma, a significant portion of other hematological and non-hematological pathologies can benefit from this innovative treatment, as the results of clinical studies are demonstrating. The clinical application of CAR-T in the setting of acute T-lymphoid leukemia, acute myeloid leukemia, solid tumors, autoimmune diseases and infections has encountered limitations that are different from those of hematological B-cell diseases. To overcome these restrictions, strategies based on different molecular engineering platforms have been devised and will be illustrated below. The aim of this manuscript is to provide an overview of the CAR-T application in pathologies other than those currently treated, highlighting both the limits and results obtained with these settings.

Synergistic integration of mRNA-LNP with CAR-engineered immune cells: Pioneering progress in immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has emerged as a revolutionary approach in the treatment of malignancies. Despite its remarkable successes, this field continues to grapple with challenges such as scalability, safety concerns, limited therapeutic effect, in vivo persistence, and the need for precise control over CAR expression. In the post-pandemic era of COVID-19 vaccine immunization, the application of messenger RNA (mRNA) encapsulated within lipid nanoparticles (LNPs) has recently garnered significant attention as a potential solution to address these challenges. This review delves into the dynamic landscape of mRNA-LNP technology and its potential implications for CAR-engineered immune cell-based immunotherapy.

A review of immune modulators and immunotherapy in infectious diseases

The human immune system responds to harmful foreign invaders frequently encountered by the body and employs defense mechanisms to counteract such assaults. Various exogenous and endogenous factors play a prominent role in maintaining the balanced functioning of the immune system, which can result in immune suppression or immune stimulation. With the advent of different immune-modulatory agents, immune responses can be modulated or regulated to control infections and other health effects. Literature provides evidence on various immunomodulators from different sources and their role in modulating immune responses. Due to the limited efficacy of current drugs and the rise in drug resistance, there is a growing need for new therapies for infectious diseases. In this review, we aim to provide a comprehensive overview of different immune-modulating agents and immune therapies specifically focused on viral infectious diseases.

Leveraging oncovirus-derived antigen against the viral malignancies in adoptive cell therapies

Adoptive cell therapies (ACTs) have revolutionized cancer immunotherapy, prompting exploration into their application against oncoviruses. Oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and Epstein-Barr virus (EBV) contribute significantly (12-25%) to human malignancies through direct or indirect oncogenic mechanisms. These viruses persistently or latently infect cells, disrupt cellular homeostasis and pathways, challenging current antiviral treatment paradigms. Moreover, viral infections pose additional risks in the setting of long-term cancer therapy and lead to morbidity and mortality. Virally encoded oncoproteins, which are tumor-restricted, immunologically foreign, and even uniformly expressed, represent promising targets for patient-tailored ACTs. This review elucidates the rationale for leveraging viral antigen-specific ACTs in combating viral-associated malignancies. On this basis, ongoing preclinical studies consolidate our understanding of harnessing ACTs against viral malignancies, underscoring their potential to eradicate viruses implicated in cancer progression. Furthermore, we scrutinize the current landscape of clinical trials focusing on virus-specific ACTs and discuss their implications for therapeutic advancement.

The enchanting canvas of CAR technology: Unveiling its wonders in non-neoplastic diseases

Chimeric antigen receptor (CAR) T cells have made a groundbreaking advancement in personalized immunotherapy and achieved widespread success in hematological malignancies. As CAR technology continues to evolve, numerous studies have unveiled its potential far beyond the realm of oncology. This review focuses on the current applications of CAR-based cellular platforms in non-neoplastic indications, such as autoimmune, infectious, fibrotic, and cellular senescence-associated diseases. Furthermore, we delve into the utilization of CARs in non-T cell populations such as natural killer (NK) cells and macrophages, highlighting their therapeutic potential in non-neoplastic conditions and offering the potential for targeted, personalized therapies to improve patient outcomes and enhanced quality of life.

Expanding the horizon of transient CAR T therapeutics using virus-free technology

The extraordinary success that chimeric antigen receptor (CAR) T cell therapies have shown over the years on fighting hematological malignancies is evidenced by the six FDA-approved products present on the market. CAR T treatments have forever changed the way we understand cellular immunotherapies, as current research in the topic is expanding even outside the field of cancer with very promising results. Until now, virus-based strategies have been used for CAR T cell manufacturing. However, this methodology presents relevant limitations that need to be addressed prior to wide spreading this technology to other pathologies and in order to optimize current cancer treatments. Several approaches are being explored to overcome these challenges such as virus-free alternatives that additionally offer the possibility of developing transient CAR expression or in vivo T cell modification. In this review, we aim to spotlight a pivotal juncture in the history of medicine where a significant change in perspective is occurring. We review the current progress made on viral-based CAR T therapies as well as their limitations and we discuss the future outlook of virus-free CAR T strategies to overcome current challenges and achieve affordable immunotherapies for a wide variety of pathologies, including cancer.

The construction of modular universal chimeric antigen receptor T (MU-CAR-T) cells by covalent linkage of allogeneic T cells and various antibody fragments

BACKGROUND

Chimeric antigen receptor-T (CAR-T) cells therapy is one of the novel immunotherapeutic approaches with significant clinical success. However, their applications are limited because of long preparation time, high cost, and interpersonal variations. Although the manufacture of universal CAR-T (U-CAR-T) cells have significantly improved, they are still not a stable and unified cell bank.

METHODS

Here, we tried to further improve the convenience and flexibility of U-CAR-T cells by constructing novel modular universal CAR-T (MU-CAR-T) cells. For this purpose, we initially screened healthy donors and cultured their T cells to obtain a higher proportion of stem cell-like memory T (TSCM) cells, which exhibit robust self-renewal capacity, sustainability and cytotoxicity. To reduce the alloreactivity, the T cells were further edited by double knockout of the T cell receptor (TCR) and class I human leukocyte antigen (HLA-I) genes utilizing the CRISPR/Cas9 system. The well-growing and genetically stable universal cells carrying the CAR-moiety were then stored as a stable and unified cell bank. Subsequently, the SDcatcher/GVoptiTag system, which generate an isopeptide bond, was used to covalently connect the purified scFvs of antibody targeting different antigens to the recovered CAR-T cells.

RESULTS

The resulting CAR-T cells can perform different functions by specifically targeting various cells, such as the eradication of human immunodeficiency virus type 1 (HIV-1)-latenly-infected cells or elimination of T lymphoma cells, with similar efficiency as the traditional CAR-T cells did.

CONCLUSION

Taken together, our strategy allows the production of CAR-T cells more modularization, and makes the quality control and pharmaceutic manufacture of CAR-T cells more feasible.

Chimeric antigen receptor-based therapies beyond cancer

Adoptive cell transfer (ACT) therapies have gained renewed interest in the field of immunotherapy following the advent of chimeric antigen receptor (CAR) technology. This immunological breakthrough requires immune cell engineering with an artificial surface protein receptor for antigen-specific recognition coupled to an intracellular protein domain for cell activating functions. CAR-based ACT has successfully solved some hematological malignancies, and it is expected that other tumors may soon benefit from this approach. However, the potential of CAR technology is such that other immune-mediated disorders are beginning to profit from it. This review will focus on CAR-based ACT therapeutic areas other than oncology such as infection, allergy, autoimmunity, transplantation, and fibrotic repair. Herein, we discuss the results and limitations of preclinical and clinical studies in that regard.

Pathogen-specific T Cells: Targeting Old Enemies and New Invaders in Transplantation and Beyond

Adoptive immunotherapy with virus-specific cytotoxic T cells (VSTs) has evolved over the last three decades as a strategy to rapidly restore virus-specific immunity to prevent or treat viral diseases after solid organ or allogeneic hematopoietic cell-transplantation (allo-HCT). Since the early proof-of-principle studies demonstrating that seropositive donor-derived T cells, specific for the commonest pathogens post transplantation, namely cytomegalovirus or Epstein-Barr virus (EBV) and generated by time- and labor-intensive protocols, could effectively control viral infections, major breakthroughs have then streamlined the manufacturing process of pathogen-specific T cells (pSTs), broadened the breadth of target recognition to even include novel emerging pathogens and enabled off-the-shelf administration or pathogen-naive donor pST production. We herein review the journey of evolution of adoptive immunotherapy with nonengineered, natural pSTs against infections and virus-associated malignancies in the transplant setting and briefly touch upon recent achievements using pSTs outside this context.

GMP development and preclinical validation of CAR-T cells targeting a lytic EBV antigen for therapy of EBV-associated malignancies

Introduction

Epstein-Barr virus (EBV) is a widely spread pathogen associated with lymphoproliferative diseases, B/ T/ NK cell lymphomas, nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC). EBV lytic reactivations contribute to the genomic instability, inflammation and tumorigenesis of NPC, promoting cancer progression. Patients with NPC refractory to standard therapies show dismal survival. EBV gp350 is an envelope protein detectable in NPC specimens intracellularly and on the cell membrane of malignant cells, and is a potential viral antigen for T cell-directed immunotherapies. The potency of T cells engineered with a chimeric antigen receptor (CAR) targeting gp350 against EBV⁺ lymphoproliferative disease was previously shown.

Methods

Here, we advanced towards preclinical and non-clinical developments of this virus-specific CAR-T cell immunotherapy against NPC. Different gp350CAR designs were inserted into a lentiviral vector (LV) backbone.

Results

A construct expressing the scFv 7A1-anti-gp350 incorporating the CD8 transmembrane and CD28.CD3ζ signaling domain (ZT002) was selected. High titer ZT002 (~1x10⁸ TU/ml) was manufactured in HEK 293T/17 suspension cells in serum free media as large-scale production under good manufacturing practices (GMP). A LV multiplicity of infection (MOI) of 1 resulted in high frequencies of functional gp350CAR⁺ T cells (>70%) at a low (<2) vector copy numbers in the genome. ZT002 was therefore used to establish gp350CAR-T batch run production methods. GMP upscaling and validation of T cell transduction and expansion in several runs resulted in average 3x10⁹ gp350CAR-T cells per batch. >80% CD3⁺ gp350CAR-T cells bound to purified gp350 protein. In vitro cytotoxicity and cytokine secretion assays (IFN-γ and TNF-α) confirmed the specificity of gp350CAR-T cells against gp350⁺ NPC, GC and lymphoma cell targets. Immunocompromised B-NDG mice (NOD.CB17-PrkdcscidIl2rgtm1/Bcgen) were challenged s.c. with a EBV⁺ NPC C666.1 cell line expressing gp350 and then treated with escalating doses of gp350CAR-T cells or with non-transduced T cells. gp350CAR-T cells promoted antitumor responses, bio-distributed in several tissues, infiltrated in tumors and rejected gp350⁺ tumor cells.

Discussion

These results support the use of gp350CAR-T cells generated with ZT002 as an Innovative New Drug to treat patients with solid and liquid EBV-associated malignancies.

DLK1-directed chimeric antigen receptor T-cell therapy for hepatocellular carcinoma

BACKGROUND

Delta-like homologue 1 (DLK1), a transmembrane protein, is highly expressed in hepatocellular carcinoma (HCC). We explored whether DLK1-directed chimeric antigen receptor (CAR) T cells can specifically eliminate DLK1-positive HCC cells and serve as a therapeutic strategy for HCC immunotherapy.

METHODS

We first characterized a homemade anti-human DLK1 monoclonal antibody, sequenced the single-chain Fragment variable (scFv) and integrated it into the second-generation CAR lentiviral vector, and then developed the DLK1-directed CAR-T cells. The cytotoxic activities of DLK1-directed CAR-T cells against different HCC cells were evaluated in vitro and in vivo.

RESULTS

The genetically modified human T cells with the DLK1-directed CARs produced cytotoxic activity against DLK1-positive HCC cells. Additionally, the DLK1-directed CARs enhanced T cell proliferation and activation in a DLK1-dependent manner. Interestingly, the DLK1-targeted CAR-T cells significantly inhibited both subcutaneous and peritoneal xenograft tumours derived from human liver cancer cell lines HepG2 or Huh-7.

CONCLUSION

DLK1-directed CAR-T cells specifically suppresses DLK1-positive HCC cells in vitro and in vivo. This study provides a novel transmembrane antigen DLK1 as a potential therapeutic target appropriate for CAR-T cell therapy, which may be further developed as a clinical therapeutic strategy for HCC immunotherapy.

Targeting SARS-CoV-2 infection through CAR-T-like bispecific T cell engagers incorporating ACE2

Objectives

Despite advances in antibody treatments and vaccines, COVID-19 caused by SARS-CoV-2 infection remains a major health problem resulting in excessive morbidity and mortality and the emergence of new variants has reduced the effectiveness of current vaccines.

Methods

Here, as a proof-of-concept, we engineered primary CD8 T cells to express SARS-CoV-2 Spike protein-specific CARs, using the extracellular region of ACE2 and demonstrated their highly specific and potent cytotoxicity towards Spike-expressing target cells. To improve on this concept as a potential therapeutic, we developed a bispecific T cell engager combining ACE2 with an anti-CD3 scFv (ACE2-Bite) to target infected cells and the virus.

Results

As in CAR-T cell approach, ACE2-Bite endowed cytotoxic cells to selectively kill Spike-expressing targets. Furthermore, ACE2-Bite neutralized the pseudoviruses of SARS-CoV, SARS-CoV-2 wild-type, and variants including Delta and Omicron, as a decoy protein. Remarkably, ACE2-Bite molecule showed a higher binding and neutralization affinity to Delta and Omicron variants compared to SARS-CoV-2 wild-type Spike proteins.

Conclusion

In conclusion, these results suggest the potential of this approach as a variant-proof, therapeutic strategy for future SARS-CoV-2 variants, employing both humoral and cellular arms of the adaptive immune response.

Immunocompromised host section: Adoptive T-cell therapy for dsDNA viruses in allogeneic hematopoietic cell transplant recipients

PURPOSE OF REVIEW

Double-stranded DNA (dsDNA) viruses remain important causes of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). As treatment options are limited, adoptive therapy with virus-specific T cells (VST) is promising in restoring immunity and thereby preventing and treating virus infections. Here we review current evidence and recent advances in the field of VST for dsDNA viruses in allogeneic HCT recipients.

RECENT FINDINGS

Four different protocols for VST generation are currently used in clinical trials, and various products including multivirus-specific and off-the-shelf products are under investigation for prophylaxis, preemptive therapy or treatment. Data from nearly 1400 dsDNA-VST applications in allogeneic HCT patients have been published and demonstrated its safety. Although Epstein-Barr virus, cytomegalovirus, and adenovirus-specific T-cell therapy studies have predominated over the past 25 years, additional human herpes viruses were added to multivirus-specific T cells over the last decade and clinical evidence for polyomavirus-specific VST has just recently emerged. Response rates of around 70-80% have been reported, but cautious interpretation is warranted as data are predominantly from phase 1/2 studies and clinical efficacy needs to be confirmed in phase 3 studies.

SUMMARY

Investigation on the 'ideal' composition of VST is ongoing. Several products recently entered phase 3 trials and may allow widespread clinical use in the near future.

Alternative CAR Therapies: Recent Approaches in Engineering Chimeric Antigen Receptor Immune Cells to Combat Cancer

For nearly three decades, chimeric antigen receptors (CARs) have captivated the interest of researchers seeking to find novel immunotherapies to treat cancer. CARs were first designed to work with T cells, and the first CAR T cell therapy was approved to treat B cell lymphoma in 2017. Recent advancements in CAR technology have led to the development of modified CARs, including multi-specific CARs and logic gated CARs. Other immune cell types, including natural killer (NK) cells and macrophages, have also been engineered to express CARs to treat cancer. Additionally, CAR technology has been adapted in novel approaches to treating autoimmune disease and other conditions and diseases. In this article, we review these recent advancements in alternative CAR therapies and design, as well as their mechanisms of action, challenges in application, and potential future directions.

Antiviral Cell Products against COVID-19: Learning Lessons from Previous Research in Anti-Infective Cell-Based Agents

COVID-19 is a real challenge for the protective immunity. Some people do not respond to vaccination by acquiring an appropriate immunological memory. The risk groups for this particular infection such as the elderly and people with compromised immunity (cancer patients, pregnant women, etc.) have the most serious problems in developing an adequate immune response. Therefore, dendritic cell (DC) vaccines that are loaded ex vivo with SARS-CoV-2 antigens in the optimal conditions are promising for immunization. Lymphocyte effector cells with chimeric antigen receptor (CAR lymphocytes) are currently used mainly as anti-tumor treatment. Before 2020, few studies on the antiviral CAR lymphocytes were reported, but since the outbreak of SARS-CoV-2 the number of such studies has increased. The basis for CARs against SARS-CoV-2 were several virus-specific neutralizing monoclonal antibodies. We propose a similar, but basically novel and more universal approach. The extracellular domain of the immunoglobulin G receptors will be used as the CAR receptor domain. The specificity of the CAR will be determined by the antibodies, which it has bound. Therefore, such CAR lymphocytes are highly universal and have functional activity against any infectious agents that have protective antibodies binding to a foreign surface antigen on the infected cells.

CAR-based therapies: opportunities for immuno-medicine beyond cancer

One of the most exciting new therapies for cancer involves the use of autologous T cells that are engineered to recognize and destroy cancerous cells. Patients with previously untreatable B cell leukaemias and lymphomas have been cured, and efforts are underway to extend this success to other tumours. Here, we discuss recent studies and emerging research aimed to extend this approach beyond oncology in areas such as cardiometabolic disorders, autoimmunity, fibrosis and senescence. We also summarize new technologies that may help to reduce the cost and increase access to related forms of immunotherapy.

Therapeutic roles of CAR T cells in infectious diseases: Clinical lessons learnt from cancer

Cancer immunotherapy has made improvements due to the advances in chimaeric antigen receptor (CAR) T cell development, offering a promising treatment option for patients who have failed to respond to traditional treatments. In light of the successful use of adoptive CAR T cell therapy for cancer, researchers have been inspired to develop CARs for the treatment of other diseases beyond cancers such as viral infectious diseases. Nonetheless, various obstacles limit the efficacy of CAR T cell therapies and prevent their widespread usage. Severe toxicities, poor in vivo persistence, antigen escape, and heterogeneity, as well as off-target effect, are key challenges that must all be addressed to broaden the application of CAR T cells to a wider spectrum of diseases. The key advances in CAR T cell treatment for cancer and viral infections are reviewed in this article. We will also discuss revolutionary CAR T cell products developed to improve and enhance the therapeutic advantages of these treatments.

CAR T Cell Immunotherapy Beyond Haematological Malignancy

Chimeric antigen receptor (CAR) T cells, which express a synthetic receptor engineered to target specific antigens, have demonstrated remarkable potential to treat haematological malignancies. However, their transition beyond haematological malignancy has so far been unsatisfactory. Here, we discuss recent challenges and improvements for CAR T cell therapy against solid tumors: Antigen heterogeneity which provides an effective escape mechanism against conventional mono-antigen-specific CAR T cells; and the immunosuppressive tumor microenvironment which provides physical and molecular barriers that respectively prevent T cell infiltration and drive T cell dysfunction and hypoproliferation. Further, we discuss the application of CAR T cells in infectious disease and autoimmunity.

Modulating immune responses to AAV by expanded polyclonal T-regs and capsid specific chimeric antigen receptor T-regulatory cells

Immune responses to adeno-associated virus (AAV) capsids limit the therapeutic potential of AAV gene therapy. Herein, we model clinical immune responses by generating AAV capsid-specific chimeric antigen receptor (AAV-CAR) T cells. We then modulate immune responses to AAV capsid with AAV-CAR regulatory T cells (Tregs). AAV-CAR Tregs in vitro display phenotypical Treg surface marker expression, and functional suppression of effector T cell proliferation and cytotoxicity. In mouse models, AAV-CAR Tregs mediated continued transgene expression from an immunogenic capsid, despite antibody responses, produced immunosuppressive cytokines, and decreased tissue inflammation. AAV-CAR Tregs are also able to bystander suppress immune responses to immunogenic transgenes similarly mediating continued transgene expression, producing immunosuppressive cytokines, and reducing tissue infiltration. Taken together, AAV-CAR T cells and AAV-CAR Tregs are directed and powerful immunosuppressive tools to model and modulate immune responses to AAV capsids and transgenes in the local environment.

Titan Cells and Yeast Forms of Cryptococcus neoformans and Cryptococcus gattii Are Recognized by GXMR-CAR

Cryptococcosis, a systemic mycosis that affects both the immunocompromised and immunocompetent, is caused by the inhalation of dehydrated yeasts or fungal spores of Cryptococcus gattii or Cryptococcus neoformans. The Cryptococcus spp. polysaccharide capsule is composed mainly of glucuronoxylomannan—GXM, its major virulence factor. The capsule thickness increases to more than 15 μm during titanization, favoring the pathogenesis of cryptococcosis. Previous studies demonstrated that cytotoxic T cells that had been bioengineered with GXM-targeting chimeric antigen receptor (GXMR-CAR) were able to recognize C. neoformans by promoting the control of titanization. GXMR-CAR, a second-generation CAR, contains a single-chain variable fragment that originates from a 18B7 clone: a human IgG4 hinge, followed by a human CD28 (transmembrane/cytoplasmic domains) and a CD3ς chain. In the current study, we redirected T cells to target distinct C. neoformans and C. gattii cell types by GXMR-CAR. Lentiviral particles carrying the GXMR-CAR sequence were used to transduce Jurkat cells, and these modified cells interacted with the GXM of the C. gattii R265 strain. Moreover, GXMR-CAR mediated the recognition of C. gattii and C. neoformans yeasts with both thin and thick polysaccharide capsules, and GXMR-CAR Jurkat cells interacted with titan cells sourced from both Cryptococcus spp. Thus, bioengineered cells using CAR can improve the treatment of cryptococcosis.

Immunotherapy with adoptive cytomegalovirus-specific T cells transfer: Summarizing latest gene engineering techniques

Cytomegalovirus (CMV) infection remains a major complication following allogeneic hematopoietic stem cell transplantation (HSCT). T cell response plays a critical role in inducing long-term immunity against CMV infection/reactivation that impairs during HSCT. Adoptive T cell therapy (ACT) via transferring CMV-specific T cells from a seropositive donor to the recipient can accelerate virus-specific immune reconstitution. ACT, as an alternative approach, can restore protective antiviral T cell immunity in patients. Different manufacturing protocols have been introduced to isolate and expand specific T cells for the ACT clinical setting. Nevertheless, HLA restriction, long-term manufacturing process, risk of alloreactivity, and CMV seropositive donor availability have limited ACT broad applicability. Genetic engineering has developed new strategies to produce TCR-modified T cells for diagnosis, prevention, and treatment of infectious disease. In this review, we presented current strategies required for ACT in posttransplant CMV infection. We also introduced novel gene-modified T cell discoveries in the context of ACT for CMV infection. It seems that these innovations are enabling to improvement and development of ACT utilization to combat posttransplant CMV infection.

Chimeric antigen receptor T-cells (CARs) in cancer treatment

BACKGROUND

Cancer is one of the leading causes of death worldwide. Chemotherapy, radiation therapy, and stem cell transplantation were the main cancer treatment approaches for several years but due to their limited effectiveness, there was a constant search for new therapeutic approaches. Cancer immunotherapy that utilizes and enhances the normal capacity of the patient's immune system was used to fight against cancer. Genetically engineered T-cells that express chimeric antigen receptors (CARs) showed remarkable anti-tumor activity against hematologic malignancies and is now being investigated in a variety of solid tumors. The use of this therapy in the last few years has been successful, achieving a great success in improving the quality of life and prolonging the survival time of patients with a reduction in remission rates. However, many challenges still need to be resolved in order for this technology to gain widespread adoption. <P> Objective: This review summarizes various experimental approaches towards the use of CAR T-cells in hematologic malignancies and solid tumors. <P> Conclusion: Finally, we address the challenges posed by CAR T-cells and discuss strategies for improving the performance of these T cells in fighting cancers.

CARs-A New Perspective to HCMV Treatment

Human cytomegalovirus (HCMV), by primary infection or reactivation, represents a great risk for immune-suppressed or compromised patients. In immunocompetent humans, the immune system suppresses the spread of HCMV during an infection, resulting in a mostly asymptomatic or mild course of the disease, whereas in immune suppressed patients, the compromised host immune response cannot control the viral infection. Multiple viral immunomodulatory mechanisms additionally contribute to immune evasion. Use of chimeric antigen receptors (CARs), a treatment strategy adapted from cancer immunotherapy, is investigated for possible application to combat HCMV and other infections in immunocompromised patients. The administration of CAR⁺ T-cells directed against HCMV antigens can bypass viral immune evasion and may complement existing treatment methods. This review gives a short overview of HCMV, the obstacles of current treatment options as well as a brief introduction to CARs and the current research situation on CAR⁺ T-cells against HCMV.

Antimicrobial immunotherapeutics: past, present and future

In this age of antimicrobial resistance (AMR) there is an urgent need for novel antimicrobials. One area of recent interest is in developing antimicrobial effector molecules, and even cell-based therapies, based on those of the immune system. In this review, some of the more interesting approaches will be discussed, including immune checkpoint inhibitors, Interferons (IFNs), Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF), Chimeric Antigen Receptor (CAR) T cells, Antibodies, Vaccines and the potential role of trained immunity in protection from and/or treatment of infection.

Nanomedicine Approach to Immunotherapy of Hepatocellular Carcinoma

In recent years, the growing studies focused on the immunotherapy of hepatocellular carcinoma and proved the preclinical and clinical promises of host antitumor immune response. However, there were still various obstacles in meeting satisfactory clinic need, such as low response rate, primary resistance and secondary resistance to immunotherapy. Tackling these barriers required a deeper understanding of immune underpinnings and a broader understanding of advanced technology. This review described immune microenvironment of liver and HCC which naturally decided the complexity of immunotherapy, and summarized recent immunotherapy focusing on different points. The ever-growing clues indicated that the instant killing of tumor cell and the subsequent relive of immunosuppressive microenvironment were both indis- pensables. The nanotechnology applied in immunotherapy and the combination with intervention technology was also discussed.

Application of 3D bioprinting in the prevention and the therapy for human diseases

Rapid development of vaccines and therapeutics is necessary to tackle the emergence of new pathogens and infectious diseases. To speed up the drug discovery process, the conventional development pipeline can be retooled by introducing advanced in vitro models as alternatives to conventional infectious disease models and by employing advanced technology for the production of medicine and cell/drug delivery systems. In this regard, layer-by-layer construction with a 3D bioprinting system or other technologies provides a beneficial method for developing highly biomimetic and reliable in vitro models for infectious disease research. In addition, the high flexibility and versatility of 3D bioprinting offer advantages in the effective production of vaccines, therapeutics, and relevant delivery systems. Herein, we discuss the potential of 3D bioprinting technologies for the control of infectious diseases. We also suggest that 3D bioprinting in infectious disease research and drug development could be a significant platform technology for the rapid and automated production of tissue/organ models and medicines in the near future.

Clinical development of CAR T cell therapy in China: 2020 update

Chimeric antigen receptor (CAR) T-cell therapy has achieved significant success in the treatment of hematological malignancies. In recent years, fast-growing CAR T clinical trials have actively explored their potential application scenarios. According to the data from the clinicaltrials.gov website, China became the country with the most registered CAR T trials in September 2017. As of June 30, 2020, the number of registered CAR T trials in China has reached 357. In addition, as many as 150 other CAR T trials have been registered on ChiCTR. Although CAR T therapy is flourishing in China, there are still some problems that cannot be ignored. In this review, we aim to systematically summarize the clinical practice of CAR T-cell therapy in China. This review will provide an informative reference for colleagues in the field, and a better understanding of the history and current situation will help us more reasonably conduct research and promote cooperation.

Genetic engineering of T cells for immunotherapy

Genetically engineered T cell immunotherapies have provided remarkable clinical success to treat B cell acute lymphoblastic leukaemia by harnessing a patient's own T cells to kill cancer, and these approaches have the potential to provide therapeutic benefit for numerous other cancers, infectious diseases and autoimmunity. By introduction of either a transgenic T cell receptor or a chimeric antigen receptor, T cells can be programmed to target cancer cells. However, initial studies have made it clear that the field will need to implement more complex levels of genetic regulation of engineered T cells to ensure both safety and efficacy. Here, we review the principles by which our knowledge of genetics and genome engineering will drive the next generation of adoptive T cell therapies.

Splice-Switching Antisense Oligonucleotides as a Targeted Intrinsic Engineering Tool for Generating Armored Redirected T Cells

Modification of specificity of T cells for the use in adoptive transfer (CAR- or TCR-redirected T cells) has revolutionized the therapy of liquid tumors and some infectious diseases. However, several obstacles are still hampering the efficacy of such potent therapy, hence concurrent modification of the function is also required to obtain successful results. Here we show the use of splice-switching antisense oligonucleotides (SSOs) as a tool to transiently modify T cell function. We demonstrate the possibility to transfect SSOs and an exogenous TCR into primary human T cells in the same electroporation reaction, without affecting viability and function of the transfected T lymphocytes. Moreover, we show that SSOs targeting T cell-specific mRNAs induce the skipping of the targeted exons, and the reduction of the protein and consequent modification of T cell function. This technical work paves the way to the use of SSOs in immune cells, not only for the knockdown of the functional isoform of the targeted proteins, but also for the protein manipulation by elimination of specific domains encoded by targeted exons.

Application of CAR-T Cell Therapy beyond Oncology: Autoimmune Diseases and Viral Infections

Adoptive cell transfer (ACT) has long been at the forefront of the battle with cancer that began last century with the therapeutic application of tumor-infiltrating lymphocytes (TILs) against melanoma. The development of novel ACT approaches led researchers and clinicians to highly efficient technologies based on genetically engineered T lymphocytes, with chimeric antigen receptor (CAR)-T cells as the most prominent example. CARs consist of an extracellular domain that represents the single-chain variable fragment (scFv) of a monoclonal antibody (mAb) responsible for target recognition and the intracellular domain, which was built from up to several signaling motifs that mediated T cell activation. The number of potential targets amenable for CAR-T cell therapy is expanding rapidly, which means that the tremendous success of this approach in oncology could be further translated to treating other diseases. In this review, we outlined modern trends and recent developments in CAR-T cell therapy from an unusual point of view by focusing on diseases beyond cancer, such as autoimmune disorders and viral infections, including SARS-CoV-2.

CAR-T cells leave the comfort zone: current and future applications beyond cancer

Chimeric antigen receptor (CAR)-T cell therapy represents a breakthrough in the immunotherapy field and has achieved great success following its approval in 2017 for the treatment of B cell malignancies. While CAR-T cells are mostly applied as anti-tumor therapy in the present, their initial concept was aimed at a more general purpose of targeting membrane antigens, thus translating in many potential applications. Since then, several studies have assessed the use of CAR-T cells toward non-malignant pathologies such as autoimmune diseases, infectious diseases and, more recently, cardiac fibrosis, and cellular senescence. In this review, we present the main findings and implications of CAR-based therapies for non-malignant conditions.

CAR-T Cells Targeting Epstein-Barr Virus gp350 Validated in a Humanized Mouse Model of EBV Infection and Lymphoproliferative Disease

Epstein-Barr virus (EBV) is a latent and oncogenic human herpesvirus. Lytic viral protein expression plays an important role in EBV-associated malignancies. The EBV envelope glycoprotein 350 (gp350) is expressed abundantly during EBV lytic reactivation and sporadically on the surface of latently infected cells. Here we tested T cells expressing gp350-specific chimeric antigen receptors (CARs) containing scFvs derived from two novel gp350-binding, highly neutralizing monoclonal antibodies. The scFvs were fused to CD28/CD3ζ signaling domains in a retroviral vector. The produced gp350CAR-T cells specifically recognized and killed gp350⁺ 293T cells in vitro. The best-performing 7A1-gp350CAR-T cells were cytotoxic against the EBV⁺ B95-8 cell line, showing selectivity against gp350⁺ cells. Fully humanized Nod.Rag.Gamma mice transplanted with cord blood CD34⁺ cells and infected with the EBV/M81/fLuc lytic strain were monitored dynamically for viral spread. Infected mice recapitulated EBV-induced lymphoproliferation, tumor development, and systemic inflammation. We tested adoptive transfer of autologous CD8⁺gp350CAR-T cells administered protectively or therapeutically. After gp350CAR-T cell therapy, 75% of mice controlled or reduced EBV spread and showed lower frequencies of EBER⁺ B cell malignant lymphoproliferation, lack of tumor development, and reduced inflammation. In summary, CD8⁺gp350CAR-T cells showed proof-of-concept preclinical efficacy against impending EBV⁺ lymphoproliferation and lymphomagenesis.

Engineered Ovarian Cancer Cell Lines for Validation of CAR T Cell Function

A set of genetically engineered isogenic cell lines is developed to express either folate receptor alpha or mesothelin, and a control cell line negative for both antigens. These cell lines also express fluorescent and bioluminescent reporter transgenes. The cell lines are used to authenticate specificity and function of a T-cell biofactory, a living vector that is developed to express proportionate amounts of engineered proteins upon engaging with disease cells through their specific antigenic biomarkers. The engineered cell lines are also used to assess the cytolytic function and specificity of primary T cells engineered with chimeric antigen receptors; and the specificity of monoclonal antibodies. The strategy described can be used to generate other cell lines to present different disease-specific biomarkers for use as quality control tools.

Advances and Challenges of CAR T Cells in Clinical Trials

As a specifically programmable, living immunotherapeutic drug, chimeric antigen receptor (CAR)-modified T cells are providing an alternative treatment option for a broad variety of diseases including so far refractory cancer. By recognizing a tumor-associated antigen, the CAR triggers an anti-tumor response of engineered patient's T cells achieving lasting remissions in the treatment of leukemia and lymphoma. During the last years, significant progress was made in optimizing the CAR design, in manufacturing CAR-engineered T cells, and in the clinical management of patients showing promise to establish adoptive CAR T cell therapy as an effective treatment option in the forefront.

CAR T Cells Beyond Cancer: Hope for Immunomodulatory Therapy of Infectious Diseases

Infectious diseases are still a significant cause of morbidity and mortality worldwide. Despite the progress in drug development, the occurrence of microbial resistance is still a significant concern. Alternative therapeutic strategies are required for non-responding or relapsing patients. Chimeric antigen receptor (CAR) T cells has revolutionized cancer immunotherapy, providing a potential therapeutic option for patients who are unresponsive to standard treatments. Recently two CAR T cell therapies, Yescarta® (Kite Pharma/Gilead) and Kymriah® (Novartis) were approved by the FDA for the treatments of certain types of non-Hodgkin lymphoma and B-cell precursor acute lymphoblastic leukemia, respectively. The success of adoptive CAR T cell therapy for cancer has inspired researchers to develop CARs for the treatment of infectious diseases. Here, we review the main achievements in CAR T cell therapy targeting viral infections, including Human Immunodeficiency Virus, Hepatitis C Virus, Hepatitis B Virus, Human Cytomegalovirus, and opportunistic fungal infections such as invasive aspergillosis.

HBV Immune-Therapy: From Molecular Mechanisms to Clinical Applications

Chronic hepatitis B virus (HBV) infection represents a worldwide public health concern with approximately 250 million people chronically infected and at risk of developing liver cirrhosis and hepatocellular carcinoma. Nucleos(t)ide analogues (NUC) are the most widely used therapies for HBV infection, but they often require long-lasting administration to avoid the risk of HBV reactivation at withdrawal. Therefore, there is an urgent need to develop novel treatments to shorten the duration of NUC therapy by accelerating virus control, and to complement the effect of available anti-viral therapies. In chronic HBV infection, virus-specific T cells are functionally defective, and this exhaustion state is a key determinant of virus persistence. Reconstitution of an efficient anti-viral T cell response may thus represent a rational strategy to treat chronic HBV patients. In this perspective, the enhancement of adaptive immune responses by a checkpoint inhibitor blockade, specific T cell vaccines, lymphocyte metabolism targeting, and autologous T cell engineering, including chimeric antigen receptor (CAR) and TCR-redirected T cells, constitutes a promising immune modulatory approach for a therapeutic restoration of protective immunity. The advances of the emerging immune-based therapies in the setting of the HBV research field will be outlined.

Development of CAR-T cells for long-term eradication and surveillance of HIV-1 reservoir

Human immunodeficiency virus type 1 (HIV-1) reservoir is a pool of latently infected cells harboring replication-competent proviral DNA that limits antiretroviral therapy. Suppression of HIV-1 by combination antiretroviral therapy (cART) delays progression of the disease but does not eliminate the viral reservoir, necessitating lifetime daily administration of antiretroviral drugs. To achieve durable suppression of viremia without daily therapy, various strategies have been developed, including long-acting antiretroviral drugs (LA-ARVs), broadly neutralizing antibodies (bNAbs), and chimeric antigen receptor T (CAR-T) cells. Here, we summarize and discuss recent breakthroughs in CAR-T cell therapies toward the eradication of HIV-1 reservoir. Although substantial challenges exist, CAR-T cell technology may serve as a promising strategy toward HIV-1 functional cure.

Cell-to-Cell Spread Blocking Activity Is Extremely Limited in the Sera of Herpes Simplex Virus 1 (HSV-1)- and HSV-2-Infected Subjects

Herpes simplex virus 1 (HSV-1) and HSV-2 can evade serum antibody-mediated neutralization through cell-to-cell transmission mechanisms, which represent one of the central steps in disease reactivation. To address the role of humoral immunity in controlling HSV-1 and HSV-2 replication, we analyzed serum samples from 44 HSV-1 and HSV-2 seropositive subjects by evaluating (i) their efficiency in binding both the purified viral particles and recombinant gD and gB viral glycoproteins, (ii) their neutralizing activity, and (iii) their capacity to inhibit the cell-to-cell virus passage in vitro All of the sera were capable of binding gD, gB, and whole virions, and all sera significantly neutralized cell-free virus. However, neither whole sera nor purified serum IgG fraction was able to inhibit significantly cell-to-cell virus spreading in in vitro post-virus-entry infectious assays. Conversely, when spiked with an already described anti-gD human monoclonal neutralizing antibody capable of inhibiting HSV-1 and -2 cell-to-cell transmission, each serum boosted both its neutralizing and post-virus-entry inhibitory activity, with no interference exerted by serum antibody subpopulations.IMPORTANCE Despite its importance in the physiopathology of HSV-1 and -2 infections, the cell-to-cell spreading mechanism is still poorly understood. The data shown here suggest that infection-elicited neutralizing antibodies capable of inhibiting cell-to-cell virus spread can be underrepresented in most infected subjects. These observations can be of great help in better understanding the role of humoral immunity in controlling virus reactivation and in the perspective of developing novel therapeutic strategies, studying novel correlates of protection, and designing effective vaccines.

Alternative Methods of Vaccine Delivery: An Overview of Edible and Intradermal Vaccines

Vaccines are recognized worldwide as one of the most important tools for combating infectious diseases. Despite the tremendous value conferred by currently available vaccines toward public health, the implementation of additional vaccine platforms is also of key importance. In fact, currently available vaccines possess shortcomings, such as inefficient triggering of a cell-mediated immune response and the lack of protective mucosal immunity. In this regard, recent work has been focused on vaccine delivery systems, as an alternative to injectable vaccines, to increase antigen stability and improve overall immunogenicity. In particular, novel strategies based on edible or intradermal vaccine formulations have been demonstrated to trigger both a systemic and mucosal immune response. These novel vaccination delivery systems offer several advantages over the injectable preparations including self-administration, reduced cost, stability, and elimination of a cold chain. In this review, the latest findings and accomplishments regarding edible and intradermal vaccines are described in the context of the system used for immunogen expression, their molecular features and capacity to induce a protective systemic and mucosal response.

Evaluation of a Fully Human, Hepatitis B Virus-Specific Chimeric Antigen Receptor in an Immunocompetent Mouse Model

Chimeric antigen receptor (CAR) T cell therapy is a promising novel therapeutic approach for cancer but also for chronic infection. We have developed a fully human, second-generation CAR directed against the envelope protein of hepatitis B virus on the surface of infected cells (S-CAR). The S-CAR contains a human B cell-derived single-chain antibody fragment and human immunoglobulin G (IgG) spacer, CD28- and CD3-signaling domains that may be immunogenic in mice. Because immunosuppression will worsen the clinical course of chronic hepatitis B, we aimed at developing a preclinical mouse model that is immunocompetent and mimics chronic hepatitis B but nevertheless allows evaluating efficacy and safety of a fully human CAR. The S-CAR grafted on T cells triggered antibody responses in immunocompetent animals, and a co-expressed human-derived safeguard, the truncated epidermal growth factor receptor (EGFRt), even induced B and T cell responses, both limiting the survival of S-CAR-grafted T cells. Total body irradiation and transfer of T cells expressing an analogous, signaling-deficient S-CAR decoy and the safeguard induced immune tolerance toward the human-derived structures. S-CAR T cells transferred after immune recovery persisted and showed long-lasting antiviral effector function. The approach we describe herein will enable preclinical studies of efficacy and safety of fully human CARs in the context of a functional immune system.

A gB/CD3 bispecific BiTE antibody construct for targeting Human Cytomegalovirus-infected cells

Bispecific T cell engager (BiTE) antibody constructs are successfully used as cancer therapeutics. We hypothesized that this treatment strategy could also be applicable for therapy of human cytomegalovirus (HCMV) infection, since HCMV-encoded proteins are abundantly expressed on the surface of infected cells. Here we show that a BiTE antibody construct directed against HCMV glycoprotein B (gB) and CD3 efficiently triggers T cells to secrete IFN-γ and TNF upon co-culture with fibroblasts infected with HCMV strain AD169, Towne or Toledo. Titration of gB expression levels in non-infected cells confirmed that already low levels of gB are sufficient for efficient triggering of T cells in presence of the BiTE antibody construct. Comparison of redirecting T cells with the bispecific antibody versus a chimeric antigen receptor (CAR) based on the same scFv showed a similar sensitivity for gB expression. Although lysis of infected target cells was absent, the BiTE antibody construct inhibited HCMV replication by triggering cytokine production. Notably, even strongly diluted supernatants of the activated T cells efficiently blocked the replication of HCMV in infected primary fibroblasts. In summary, our data prove the functionality of the first BiTE antibody construct targeting an HCMV-encoded glycoprotein for inhibiting HCMV replication in infected cells.

Chimeric antigen receptor-engineered T-cell therapy for liver cancer

BACKGROUND

Chimeric antigen receptor-engineered T-cell (CAR-T) therapy is a newly developed immunotherapy used in the treatment of cancers. Because CAR-T therapy has shown great success in treating CD19-positive hematological malignancies, its application has been explored in the treatment of solid tumors, such as liver cancer. In this review, we discuss the immune characteristics of liver cancer, the obstacles encountered during the application of CAR-T therapy, and preclinical and clinical progress in the use of CAR-T therapy in patients with liver cancer.

DATA SOURCES

The data on CAR-T therapy related to liver cancers were collected by searching PubMed and the Web of Science databases prior to December 2017 with the keywords "chimeric antigen receptor", "CAR-T", "liver cancer", "hepatocellular carcinoma", and "solid tumor". Additional articles were identified by manual search of references found in the primary articles. The data for clinical trials were collected by searching ClinicalTrials.gov.

RESULTS

The liver has a tolerogenic nature in the intrahepatic milieu and its tumor microenvironment significantly affects tumor progression. The obstacles that reduce the efficacy of CAR-T therapy in solid tumors include a lack of specific tumor antigens, limited trafficking and penetration of CAR-T cells to tumor sites, and an immunosuppressive tumor microenvironment. To overcome these obstacles, several strategies have emerged. In addition, several strategies have been developed to manage the side effects of CAR-T, including enhancing the selectivity of CARs and controlling CAR-T activity. To date, no clinical trials of CAR-T therapy against HCC have been completed. However, preclinical studies in vitro and in vivo have shown potent antitumor efficacy. Glypican-3, mucin-1, epithelial cell adhesion molecule, carcinoembryonic antigen, and other targets are currently being studied.

CONCLUSIONS

The application of CAR-T therapy for liver cancer is just beginning to be explored and more research is needed. However, we are optimistic that CAR-T therapy will offer a new approach for the treatment of liver cancers in the future.

CAR T Cells in Trials: Recent Achievements and Challenges that Remain in the Production of Modified T Cells for Clinical Applications

The adoptive transfer of chimeric antigen receptor (CAR)-modified T cells is attracting growing interest for the treatment of malignant diseases. Early trials with anti-CD19 CAR T cells have achieved spectacular remissions in B-cell leukemia and lymphoma, so far refractory, very recently resulting in the Food and Drug Administration approval of CD19 CAR T cells for therapy. With further applications and increasing numbers of patients, the reproducible manufacture of high-quality clinical-grade CAR T cells is becoming an ever greater challenge. New processing techniques, quality-control mechanisms, and logistic developments are required to meet both medical needs and regulatory restrictions. This paper summarizes the state-of-the-art in manufacturing CAR T cells and the current challenges that need to be overcome to implement this type of cell therapy in the treatment of a variety of malignant diseases and in a greater number of patients.

Turning the tables on cytomegalovirus: targeting viral Fc receptors by CARs containing mutated CH2-CH3 IgG spacer domains

Background

During infection with human cytomegalovirus (HCMV) several viral proteins occur on cell surfaces in high quantity. We thus pursue an HLA-independent approach for immunotherapy of HCMV using chimeric antigen receptors (CARs) and bispecific BiTE^® antibody constructs. In this context, HCMV-encoded proteins that mediate viral immune evasion and bind human IgG might represent particularly attractive target antigens. Unlike in observations of similar approaches for HIV and hepatitis B and C viruses, however, HCMV-infected cells develop a striking resistance to cytotoxic effector functions at later stages of the replication cycle. In our study we therefore wanted to test two hypotheses: (1) CAR T cells can efficiently inhibit HCMV replication independently from cytotoxic effector functions, and (2) HCMV can be targeted by CH2–CH3 IgG spacer domains that contain mutations previously reported to prevent exhaustion and to rescue CAR T cell function in vivo.

Methods

Replication of GFP-encoding recombinant HCMV in fibroblasts in the presence and absence of supernatants from T cell co-cultures plus/minus cytokine neutralizing antibodies was analyzed by flow cytometry. CARs with wild type and mutated CH2–CH3 domains were expressed in human T cells by mRNA electroporation, and the function of the CARs was assessed by quantifying T cell cytokine secretion.

Results

We confirm and extend previous evidence of antiviral cytokine effects and demonstrate that CAR T cells strongly block HCMV replication in fibroblasts mainly by combined secretion of IFN-γ and TNF. Furthermore, we show that fibroblasts infected with HCMV strains AD169 and Towne starting from day 3 have a high capacity for binding of human IgG1 and also strongly activate T cells expressing a CAR with CH2–CH3 domain. Importantly, we further show that mutations in the CH2–CH3 domain of IgG1 and IgG4, which were previously reported to rescue CAR T cell function by abrogating interaction with endogenous Fc receptors (FcRs), still enable recognition of FcRs encoded by HCMV.

Conclusions

Our findings identify HCMV-encoded FcRs as an attractive additional target for HCMV immunotherapy by CARs and possibly bispecific antibodies. The use of specifically mutated IgG domains that bind to HCMV-FcRs without recognizing endogenous FcRs may supersede screening for novel binders directed against individual HCMV-FcRs.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1394-x) contains supplementary material, which is available to authorized users.

Interplay between circadian clock and viral infection

The circadian clock underpins most physiological conditions and provides a temporal dimension to our understanding of body and tissue homeostasis. Disruptions of circadian rhythms have been associated with many diseases, including metabolic disorders and cancer. Recent literature highlights a role for the circadian clock to regulate innate and adaptive immune functions that may prime the host response to infectious organisms. Viruses are obligate parasites that rely on host cell synthesis machinery for their own replication, survival and dissemination. Here, we review key findings on how circadian rhythms impact viral infection and how viruses modulate molecular clocks to facilitate their own replication. This emerging area of viral-clock biology research provides a fertile ground for discovering novel anti-viral targets and optimizing immune-based therapies.

Tumor-targeting domains for chimeric antigen receptor T cells

Immunotherapy with chimeric antigen receptor (CAR) T cells has been advancing steadily in clinical trials. Since the ability of engineered T cells to recognize intended tumor-associated targets is crucial for the therapeutic success, antigen-binding domains play an important role in shaping T-cell responses. Single-chain antibody and T-cell receptor fragments, natural ligands, repeat proteins, combinations of the above and universal tag-specific domains have all been used in the antigen-binding moiety of chimeric receptors. Here we outline the advantages and disadvantages of different domains, discuss the concepts of affinity and specificity, and highlight the recent progress of each targeting strategy.

Immunotherapy of hepatocellular carcinoma using chimeric antigen receptors and bispecific antibodies

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide with an overall survival rate of less than 15% in developed countries. Despite attempts at new therapeutic strategies, the majority of patients succumb to this cancer. Buttressed by the highly successful clinical impact in melanoma, immunotherapy is gaining momentum as the next treatment modality for many human cancers. Chimeric antigen receptors (CAR) contain the antigen binding moieties of a monoclonal antibody and the co-stimulatory and signaling domains associated with effector receptor signaling. Bispecific antibodies (BsAb) combine the binding specificities of two different monoclonal antibodies, one activating a receptor on a killer effector cell, while the other engaging a tumor-associated antigen to initiate tumor cytotoxicity. In this review, we survey the HCC targets for which CARs and bispecific antibodies have been generated. The pros and cons of these targets for T-cell and Natural Killer cell based immunotherapy will be discussed.