Human Allergin‑1 Antibody

MCA32 (Mast Cell Antigen; also Allergin-1 and c17orf60) is a 70 kDa member of the Ig Superfamily. It is expressed on mast cells, basophils, neutrophils and macrophages, and is reported to negatively regulate allergic mediator release from mast cells. In particular, MCA32 interacts with Fc epsilon RI. Upon IgE mediated Fc epsilon RI aggregation and activation, MCA32 recruits Tyr phosphatases to a Fc epsilon RI tetrameric complex, dampening IgE receptor downstream signaling. Mature human MCA32 is a monomeric type I transmembrane glycoprotein that is 324 amino acids (aa) in length (aa 20-343) (SwissProt #:Q7Z6M3). It contains two C2-type Ig domains (aa 35-118 and 123-217) in the extracellular region (aa 20-227), plus a 95 aa cytoplasmic domain that possesses two ITIM motifs. Two 40 kDa splice variants exist that show deletions of the Ig-like domains. One isoform termed MCA32S1 is missing aa 128-217, while a second isoform called MCA32S2 is missing aa 33-122. This second isoform represents the antigen used for immunization in this product (GenBank #:BAJ08253).  Over aa 29-131, the Allergin-1S2 isoform shares 100% sequence identity with human Allergin-1L full length isoform and only 24% aa sequence identity with mouse MCA32.