Rabbit anti- Human PD-1/CD279 mAb(CAP) (RMK0127)

Programmed Death-1 (PD-1), also known as Programmed cell death protein and CD279, is an extensively studied immune checkpoint inhibitory receptor. Given PD-1's role in peripheral tolerance, it is not surprising that increased PD-1 expression is a mechanism for immune escape, which is permissive for cancer growth and metastasis. PD‐1 is encoded by the PDCD1 gene. The PD-1 glycoprotein is a monomeric 50-55kDa type 1 transmembrane protein that belongs to the immunoglobulin (Ig) superfamily. PD-1 expression and induction have been well studied. It is expressed in CD4+ and CD8+ T cells as well as B cells, macrophages, some dendritic cell subsets and NK cells. PD-1 is induced by T cell receptor (TCR) signaling as well as interleukin 2 (IL-2), IL-7 and type 1 interferons. A variety of reagents are used to experimentally induce PD-1 expression, including, phorbol 12-myristate 13 acetate, ionomycin, concanavalin A, CD3/CD28 antibodies, or most notably lymphocytic choriomeningitis virus in vivo. PD-1 expression is also regulated post-translationally. The PD-1 extracellular domain is glycosylated at asparagine (N) residues N49 and N72 while in the endoplasmic reticulum. PD-1 subsequently transits to the golgi apparatus where it is fucosylated at the same sites by the core fucosylase FUT8. This post translational modification represents a novel therapeutic target as T cells have a more robust anticancer response due to reduced surface expression of de-fucosylated PD-1. PD-1 is polyubiquinated at lysine (K) residue K48 by the E3 ligase F-Box 38 (FBX028) which results in PD-1 degradation via the proteosome.