CAR-T Cells: The Pioneers of Immunotherapy

On almost every cell in the body, endogenous peptides (antigens) are presented by intracellular proteins to patrolling T cells via the major histocompatibility complex (MHC). This so-called antigen presentation provides the T cells with information about which proteins are being synthesized in the respective cells at that time. If a cell is infected by a virus or undergoes a malignant genetic transformation, this highly regulated mechanism ensures that the foreign or mutated peptides are presented to the cells of the immune system. Each T cell has a specific T cell receptor (TCR) that constantly scans the organism for foreign signals and/or degenerated cells. As soon as a potential threat is recognized, the T cells trigger an immune response and other cells of the immune system, such as cytotoxic T cells, are recruited. T cells are precise and efficient detectors of foreign antigens, be they pathogenic invaders or malignant cells [2].

But how are CARs used for therapeutic purposes to treat cancer or other diseases? This is done via the CAR-T cell therapy, which begins with the removal of T cells from the patient. These are genetically modified to express CARs on their surface and then cultivated to be returned to the patient's body. There, the CAR-T cells are designed to bind the foreign antigens with their specific antibody fragment, thereby generating a cytotoxic immune response and combating the patient's disease [7].

Advances in CAR-T cell therapy have had a revolutionary impact on tumor treatment. Despite the success, challenges remain, such as the limited persistence and efficacy of CAR-T cells. To overcome these difficulties and expand the therapeutic potential, the integration of the CRISPR/Cas9 system has already proven to be a precise and powerful tool [8].

CRISPR/Cas9 technology is based on a principle of bacterial immune defense and has established itself as a pioneering method in gene editing. If a bacterium is infected by a virus or phage, the bacterium integrates parts of the foreign genetic material into its own DNA. Multiple infections by different viruses/phages result in a collection of short sequences of foreign DNA (so-called "spacers"), which are separated from each other by short, repetitive sequences. Together they form the CRISPR locus (Clustered Regularly Interspaced Short Palindromic Repeats), which the bacteria use to defend themselves against infections. Upon reinfection, RNA molecules are synthesized from the CRISPR locus, which are referred to as sgRNA (single guide RNA) and fused with the Cas9 protein. Cas9 serves as an endonuclease and is guided by the sgRNA to the corresponding section on the foreign DNA. There, Cas9 catalyzes a double-strand break in the DNA, which leads to the destruction of the virus.

CRISPR/Cas9 is already being used in science to optimize CAR-T cells. The therapeutic efficacy of CAR-T cells depends on the effector functions of the patient's T cells. The effector function describes the ability of the T cells to induce a cytotoxic immune response against the infected or mutated cells. However, the immunosuppressive microenvironment of the tumor leads to T cell exhaustion, which in turn causes poor expansion and persistence of CAR-T cells. Editing inhibitory checkpoint receptors and certain transcription factors using CRISPR helps to curb T cell exhaustion [9]. In addition, the CRISPR/Cas9 system enables targeted adaptations to improve the binding affinity of CAR-T cells towards target antigens. These approaches can increase the efficacy of immunotherapy and counteract the problems associated with the use of CAR-T cells.

However, there are also challenges associated with the CRISPR/Cas9 system. Off-target mutations, where the genetic modifications could have unintended effects on other genes, pose a major risk. Strategies such as the optimized design of sgRNAs and the selection of different Cas nucleases are crucial to minimize these side effects [8].

BPS Bioscience offers a wide range of high-quality products for your CAR-T cell therapy research.  Lentiviruses are used for the transfer of CAR genes into the harvested T cells. For this purpose, lentiviruses with different antigen specificities are offered, which primarily enable the efficient development of CAR-T cells for the treatment of hematological malignancies, such as B-cell tumors. In addition, the TCR CRISPR/Cas9 lentiviruses offer the possibility of targeted genetic modification of TCR genes. Various knockout and/or reporter cell lines can be used to investigate the functions of immune cells, such as cytotoxic T cells, or key molecules, like NFAT (production of cytokines). The Untransduced T Cells can be used as a negative control in experiments with CAR-T cells to study specific effects.

BPS Bioscience products pave the way for your work on and with CAR-T cells.  Discover some of BPS Bioscience's highlight products for the CRISPR/Cas9 system and CAR-T cells:

CAR-T cell therapy is proving to be a breakthrough in cancer treatment and its application extends beyond tumors. Through technologies such as CAR-T cell therapy and the CRISPR/Cas9 system, the future of treating cancer and many other diseases that were considered "incurable" in the past looks very promising.

Our partner BPS Bioscience provides advanced tools for research on CAR-T cells and the CRISPR/Cas9 system. With further research, this could mean a revolution in disease treatment.