What Is an Antigen Receptor?

T cell antigen receptor

There is no high frequency mutation mechanism in TCR, so compared to BCR, the changes of CDR1 and CDR2 are still limited to the changes of different V gene fragments in germline genes. However, high-frequency mutations in the vaVB chain gene of spleen T cells have also been detected in mice and humans; therefore, it seems that it is possible to have somatic high-frequency mutations in the Va and VB genes of TCR, but the number is not high after all. And it is unclear whether these mutant genes can be expressed as TCR receptors on the cell surface ^[1]

For cellular immunotherapy, the monitoring and evaluation of its efficacy is not simply determined by the level of immune activity of T cells or the strength of the immune response, but is related to complex molecular immunological factors.

The National Institutes of Health (NIH) Cancer Research Center proposes a new point of view: The main factor causing the reduction or disappearance of tumors in patients is cloned T cell receptors.

In 2007, the University of London published a review article: "Monoclonal T cell receptor gene-a new cancer treatment agent". This article focuses on the role of cloned T cell receptors in immunity.

The Seattle Cancer Research Center in the United States published a "Tumor Autoimmune Cell Therapy" article in the New England Journal of Medicine (NEMJ) in June 2008, stating that T cells taken from a 52-year-old melanoma patient were cloned in vitro and subjected to antigen Stimulate back into the patient. A review after two months did not reveal any tumors, and tumors did not recur in the following 22 months.

BCR and TCR recognize antigens through antigen-binding sites. The antigen-binding site of BCR is composed of three CDRs of the light and heavy chains. The antigen-binding site of TCR is composed of three CDRs of the a, B, or 8 chains. They are CDR1, CDR2, CDR3, and are interleaved between four framework regions (FR), namely FR1CDR1FR2CDR2FR3-CDR3-FR4. CDR1, 2, 3 are composed of antigen binding sites, and the diversity of their sequences determines the diversity of antigen recognition ^[1] .