Expression of Recombinant Human Programmed Cell Death Protein-1 and Development of Camel Polyclonal Antibody

Programmed cell death protein-1 (PD-1) is a membrane receptor expressed on the surface of T and B lymphocytes, monocytes, natural killers, and dendritic cells. In cancer, the PD-1/PD-L1 system prevents the proliferation of T lymphocytes and causes the release of cytokines and cytotoxicity, which leads to the apoptosis of tumor-specific T cells, thereby preventing the immune response to cancer cells. 

In this study, the extracellular part of the humanized PD-1 protein was cloned and expressed, and the protein was injected as an antigen into a camel (Camelus dromedarius) to obtain a camel polyclonal antibody against PD-1 protein. 

The obtained results indicate the proper expression of the protein in the prokaryotic system. Also, using various tests, such as ELISA and western blot, it was confirmed that the polyclonal antibody obtained from camel can identify PD-1 protein. 

This study showed that because of the advantages, such as the ability to bind multiple epitopes, camel polyclonal antibodies can be used in antibody-based research for effective and strong molecular applications to detect PD-1 receptors.