Anti-Human MRGPRX2 (extracellular) Antibody

MRGPRX2, also known as Mas-related G protein-coupled receptor member X2, is a member of the seven transmembrane G protein-coupled receptor (GPCR) superfamily and the Mas-related subfamily branch of the rhodopsin-like class A GPCRs or Mas-related G protein-coupled receptors (Mrgprs).^1,2

Mrgprs first described 25 years ago, comprise more than 50 receptors in humans and rodents, most of which are still considered orphan receptors, that is, receptors with no identified endogenous or synthetic ligands.^1.2

The MRGPRX subfamily consists of four proteins (MRGPRX1 to MRGPRX4). The four proteins have sequence similarity with the MrgA Mas-related subfamily, however, the MRGPRX genes are only present in primates with no true orthologues in mice or rats. ^1,2

MRGPRX2 highest expression is observed in mast cells, although it has also been identified in other peripheral blood cells, including basophils and eosinophils, and at low levels in other tissues, such as the gastrointestinal tract and the central nervous system.^1.2

The expression and function of MRGPRX2 in mast cells garnered considerable interest, as these cells play a crucial role in the immune system and are involved in allergic reactions and inflammation. Indeed, MRGPRX2 activation in mast cells, triggers a signaling pathway that leads to the release of various inflammatory mediators, such as histamine, cytokines, and chemokines. This release of mediators contributes to the initiation and amplification of inflammatory responses. ^3-5

The mast cell-mediated classical allergic response, involves crosslinking of high affinity immunoglobulin E (IgE) receptor (FcεRI) on mast cells with allergen, which then release a wide range of pre-stored inflammatory mediators (histamine, serotonin, protease), followed by de novo synthesis of mediators (prostaglandins and leukotrienes) and a variety of cytokines such as interleukin (IL)-4, IL-5, IL-9, and IL-13. ^3-5

MRGPRX2 has been linked to pseudo allergic reactions, which mimic true allergic reactions but do not involve IgE antibodies. Pseudo allergic reactions can be triggered by substances that directly activate MRGPRX2 on mast cells, leading to the release of histamine and other inflammatory mediators.^3-5

In addition, expression of MRGPRX2 in sensory neurons, may contribute to the sensation of itch and pain, thus highlighting its role in neurogenic inflammation beyond classical allergic responses.^3-5