Aslı Babayakalı1, Oytun Erbaş2

1Institute of Experimental Medicine, Gebze-Kocaeli, Turkey
2Department of Physiology, Medical Faculty of Demiroğlu Bilim University, Istanbul, Turkey

Keywords: Cancer immunotherapy, immune checkpoint, monoclonal antibody, PD-1 inhibition, PD-L1 inhibition


In response to a foreign organism or material, our bodies react with a variety of immunological agents. This response mechanism is called immunogenicity. While some of the proteins that regulate the immune response function to activate this response, some of them are responsible for inhibiting this response. The main "brake" proteins involved in this negative regulation are cytotoxic T-lymphocyte-associated protein-4, programmed cell death protein-1 (PD-1), T-cell immunoglobulin and mucin domain-containing protein-3, and lymphocyte-activation gene-3. The cell can differentiate endogenous and exogenous substances through these brakes and other signal pathways. In the presence of brake proteins, the tumor cells are not perceived as a threat by the immune system, so a corresponding response does not occur. To generate this response, drugs containing monoclonal antibodies are produced for use in cancer treatments. Monoclonal antibodies are designed to block braking processes while also eliciting an immunological response. In this review, the PD-1 and programmed cell death-ligand 1 pathway and cancer immunotherapy are mentioned.

Conflict of Interest

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Financial Disclosure

The authors received no financial support for the research and/or authorship of this article.