STARTER's Featured Product Recommendation: PD-1 Functional Antibodies.

PD-1 is a 50-55 kDa cell surface receptor encoded by the Pdcd1 gene, which belongs to the CD28 family of the Ig superfamily. PD-1 is transiently expressed on CD4 and CD8 thymocytes, as well as activated T and B lymphocytes and myeloid cells. Following successful antigen elimination, PD-1 expression decreases. Additionally, Pdcd1 mRNA is expressed in developing B lymphocytes at the pre-B cell stage.

The structure of PD-1 includes an ITIM (immunoreceptor tyrosine-based inhibitory motif), indicating that PD-1 negatively regulates TCR signaling. PD-1 signals by binding to its two ligands, PD-L1 and PD-L2, both members of the B7 family. Upon ligand binding, PD-1 signaling inhibits T cell activation, leading to reduced proliferation, cytokine production, and T cell death. Furthermore, PD-1 is known to play a critical role in peripheral tolerance and the prevention of autoimmune diseases in mice, as PD-1 knockout animals exhibit dilated cardiomyopathy, splenomegaly, and loss of peripheral tolerance.

Induced PD-L1 expression is common in many tumors, including squamous cell carcinoma, colon adenocarcinoma, and breast cancer. Overexpression of PD-L1 increases tumor cell resistance to CD8 T cell-mediated lysis. In mouse melanoma models, therapeutic antibodies blocking the interaction between PD-L1 and its receptor PD-1 can temporarily suppress tumor growth. For these reasons, anti-PD-1-mediated immunotherapy is currently being explored as a cancer treatment.

The Immune Regulation Mechanism of the PD-1/PD-L1 Axis

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Data Presentation

Anti-tumor efficacy of S0B0594 in B16-OVA tumor-bearing mice