What is PD1

Creative Biolabs provides our customers with knowledge sharing related to immune checkpoint molecule PD1 to explore the complexities and unveil the role of PD1.

Introduction to PD1

The immune checkpoint molecules are key players in regulating immune responses, preventing excessive immune activation and maintaining self-tolerance. One such checkpoint molecule is PD1, a transmembrane protein that is predominantly expressed on the surface of T cells, B cells, and natural killer cells. PD1 plays a critical role in controlling immune responses and preventing excessive immune activation, which can lead to autoimmune diseases and tissue damage.

The discovery of PD1 as a critical immune checkpoint molecule has led to the development of PD1 inhibitors, a class of drugs that block the interaction between PD1 and its ligands, thereby restoring T cell function and promoting antitumor immunity.

PD1 PDL1 blockade.Fig. 1 PD1 PDL1 blockade.

Ligands that Interact with PD1

PD1 has two known ligands, PD-L1 (Programmed Death Ligand-1) and PD-L2 (Programmed Death Ligand-2), which are expressed on various cells, including tumor cells and antigen-presenting cells (APCs). PD-L1 and PD-L2 are two structurally related proteins that interact with PD1 to regulate immune responses. The binding of PD-L1 and PD-L2 to PD1 is a complex process that involves multiple interactions between the proteins.

  • The binding of PD-L1 to PD1 involves a large interface with multiple hydrogen bonds and hydrophobic interactions.
  • The binding of PD-L2 to PD1 is more polar and involves fewer hydrogen bonds.

Application of PD1

The salience of PD1 in the regulation of immune responses is underscored by its involvement in a sundry of immune-related maladies, encompassing autoimmune diseases, infectious diseases, and cancer.

  • Disordered PD1 functionality in autoimmune diseases can result in the activation of self-reactive T cells, instigating tissue damage and inflammatory cascades.
  • In the context of infectious diseases, augmented PD1 expression can impede T cell activity, subsequently postponing the expulsion of pathogens.
  • As regards cancer, the PD1/PD-L1 interplay constitutes a pivotal mechanism facilitating tumor cell evasion from immune surveillance, thereby allowing them to proliferate and metastasize unrestrainedly.

Therefore, PD1 inhibitors represent a therapeutic class of drugs that antagonize the interaction between PD1 and its cognate ligands, thereby boosting T cell responses and engendering antitumor immunity. These drugs have been ratified for the treatment of diverse cancers, including melanoma, non-small cell lung cancer, renal cell carcinoma, and Hodgkin's lymphoma.

Research Services We Offer

At Creative Biolabs, we offer a wide range of research services to support PD1-related research, including,

Our team of experienced scientists and technicians can provide customized solutions to meet your specific research needs, from assay development and validation to data analysis and interpretation.

PD1 is a complex immune checkpoint molecule that plays a critical role in regulating immune responses and maintaining self-tolerance. The blockade of PD1 has emerged as a promising strategy for cancer immunotherapy. Creative Biolabs is committed to supporting PD1-related research with high-quality research services and customized solutions.


  1. Robert C, et al. Nivolumab in previously untreated melanoma without BRAF mutation. New England Journal of Medicine, 2015, 22; 372(4): 320-30.
  2. Topalian S L, et al. Targeting the PD-1/B7-H1(PD-L1) pathway to activate anti-tumor immunity. Current opinion in immunology. 2012, 1; 24(2): 207-12.

All listed customized services & products are for research use only, not intended for pharmaceutical, diagnostic, therapeutic, or any in vivo human use.