CAR T cells: Living HIV drugs

Targeting the HIV reservoir: chimeric antigen receptor therapy for HIV cure

ABSTRACT

Although antiretroviral therapy (ART) can reduce the viral load in the plasma to undetectable levels in human immunodeficiency virus (HIV)-infected individuals, ART alone cannot completely eliminate HIV due to its integration into the host cell genome to form viral reservoirs. To achieve a functional cure for HIV infection, numerous preclinical and clinical studies are underway to develop innovative immunotherapies to eliminate HIV reservoirs in the absence of ART. Early studies have tested adoptive T-cell therapies in HIV-infected individuals, but their effectiveness was limited. In recent years, with the technological progress and great success of chimeric antigen receptor (CAR) therapy in the treatment of hematological malignancies, CAR therapy has gradually shown its advantages in the field of HIV infection. Many studies have identified a variety of HIV-specific CAR structures and types of cytolytic effector cells. Therefore, CAR therapy may be beneficial for enhancing HIV immunity, achieving HIV control, and eliminating HIV reservoirs, gradually becoming a promising strategy for achieving a functional HIV cure. In this review, we provide an overview of the design of anti-HIV CAR proteins, the cell types of anti-HIV CAR (including CAR T cells, CAR natural killer cells, and CAR-encoding hematopoietic stem/progenitor cells), the clinical application of CAR therapy in HIV infection, and the prospects and challenges in anti-HIV CAR therapy for maintaining viral suppression and eliminating HIV reservoirs.

Targeted delivery methods for RNA interference are necessary to obtain a potential functional cure for HIV/AIDS

Ribonucleic acid (RNA) is of great interest in many different therapeutic areas including infectious diseases such as immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). Thanks to current, advanced treatments for HIV, the diagnosis is no longer a death sentence. However, even with these treatments, latency is suggested to persist in T-lymphocyte-rich tissues including gut-associated lymphatic tissue (GALT), spleen, and bone marrow making HIV an incurable disease. Therefore, it is important to design systems that can effectively deliver therapeutics to these tissues to fight latent infection and find a functional cure. Numerous therapeutics ranging from small molecules to cell therapies have been explored as a cure for HIV but have failed to maintain therapeutic longevity. RNA interference (RNAi) provides a unique opportunity to achieve a functional cure for those who suffer from chronic HIV/AIDS by suppressing replication of the virus. However, RNA has certain imitations in delivery as it cannot be delivered without a carrier due to its negative charge and degradation from endogenous nucleases. Here, we provide a detailed analysis of explored systems for siRNA delivery for HIV/AIDS in the context of RNA therapeutic design and nanoparticle design. In addition, we suggest strategies that should be used to target specific tissues that are rich in lymphatic tissue.

Allogeneic gene-edited HIV-specific CAR-T cells secreting PD-1 blocking scFv enhance specific cytotoxic activity against HIV Env+ cells invivo

HIV-specific chimeric antigen receptor (CAR) T-cells have been developed to target HIV-1 infected CD4⁺ T-cells that express HIV Env proteins. However, T cell exhaustion and the patient-specific autologous paradigm of CAR-T cell hurdled clinical applications. Here, we created HIV-specific CAR-T cells using human peripheral blood mononuclear cells and a 3BNC117-E27 (3BE) CAR construct that enabled the expression of programmed cell death protein (PD-1) -blocking scFv E27 and the single-chain variable fragment of the HIV-1-specific broadly neutralizing antibody 3BNC117 to target native HIV Env. Compared with T cells expressing 3BNC117-CAR alone, 3BE CAR-T cells showed greater cytotoxic activity against HIV Env⁺ cells with stronger proliferation capability, higher killing efficiency, and enhanced cytokine secretion in the presence of HIV Env-expressing cells. Furthermore, we manufactured TCR-deficient 3BE CAR-T cells through gene editing and demonstrated that these CAR-T cells could effectively kill HIV Env ​⁺ ​cells in vivo without the occurrence of severe graft-versus-host disease (GvHD) in NSG mice. These data suggest that we have provided a feasible approach to the generation of "off-the-shelf" anti-HIV CAR-T cells in combination with PD-1 checkpoint blockade immunotherapy, which can be a powerful therapeutic candidate for the functional cure of HIV.

Single-cell transcriptome landscape and antigen receptor dynamic during SARS-CoV-2 vaccination

Vaccination by inactivated vaccine is an effective strategy to prevent the COVID-19 pandemic. However, the detailed molecular immune response at single-cell level is poorly understood. In this study, we systematically delineated the landscape of the pre- and post-vaccination single-cell transcriptome, TCR (T cell antigen receptor) and BCR (B cell antigen receptor) expression profile of vaccinated candidates. The bulk TCR sequencing analysis of COVID-19 patients was also performed. Enrichment of a clonal CD8⁺ T cell cluster expressing specific TCR was identified in both vaccination candidates and COVID-19 patients. These clonal CD8⁺ T cells showed high expression of cytotoxicity, phagosome and antigen presentation related genes. The cell–cell interaction analysis revealed that monocytes and dendritic cells could interact with these cells and initiate phagocytosis via ICAM1-ITGAM and ITGB2 signaling. Together, our study systematically deciphered the detailed immunological response during SARS-CoV-2 vaccination and infection. It may facilitate understanding the immune response and the T-cell therapy against COVID-19.

Current status and perspective of CAR-T and CAR-NK cell therapy trials in Germany

Chimeric antigen receptor (CAR)-T cell therapies are on the verge of becoming powerful immunotherapeutic tools for combating hematological diseases confronted with pressing medical needs. Lately, CAR-NK cell therapies have also come into focus as novel therapeutic options to address hurdles related to CAR-T cell therapies, such as therapy-induced side effects. Currently, more than 500 CAR-T and 17 CAR-NK cell trials are being conducted worldwide including the four CAR-T cell products Kymriah, Yescarta, Tecartus and Breyanzi, which are already available on the market. Most CAR-T cell-based gene therapy products that are under clinical evaluation consist of autologous enriched T cells, whereas CAR-NK cell-based approaches can be generated from allogeneic donors. Besides modification based on a second-generation CAR, more advanced CAR-immune cell therapeutics are being tested, which utilize precise insertion of genes to circumvent graft-versus-host disease (GvHD) or employ a dual targeting approach and adapter CARs in order to avoid therapy resistance caused by antigen loss. In this review, we are going to take a closer look at the commercial CAR-T cell therapies, as well as on CAR-T and CAR-NK cell products, which are currently under evaluation in clinical trials, that are being conducted in Germany.