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allow CAR-T cells to recognize cell surface tumor antigens leading to antigen-specific T-cell activation, proliferation, and cytokine production. Many CARs are also designed with elements that enhance T-cell persistence and activity.

After a CAR is designed, it is introduced into T-cells. Initially, through leukapheresis, peripheral blood mononuclear cells from a patient are collected and the blood is separated into different components. Once the immune cells are sequestered, the CAR constructs are transfected into T-cells using plasmid transfection, mRNA or viral vector transduction. More recent approaches to genetically altered T-cells include gene editing tools like CRISPR that create a double stranded break at a particular site within the genome and introduce the CAR gene. Although complex, this technique minimizes the risk of unrestrained genomic integration. The T-cells are then infused back into the patient.

The benefits of CAR-T-cell therapy include the MHC independent antigen recognition CAR-T cells provide. This lessens the impact of mechanisms used by tumor cells for immune escape such as the downregulation of MHC molecules. CAR-T-cells can also be used in patients regardless of their specific human leukocyte antigen (HLA) type. HLA protein markers are found on most cells in the body and allow the immune system to identify “self”. CAR-T-cells also allow for antigens other than proteins, like carbohydrates and lipids to be recognized.

Limitations to CAR-T-cell therapy include the identification of tumor specific target antigens. The binding of CARs is limited to molecules present on the surface of tumor cells. To select optimal antigens for targeting, the antigen needs to be selectively expressed on tumor cells at