Butyrophilin 1A1 (BTN1A1) is a glycoprotein belonging to the butyrophilin (BTN) family which collectively modulates immune responses, through excitatory and inhibitory signals targeting immune cells. Butyrophilins are composed of two extracellular immunoglobulin domains and a transmembrane region, with a conserved B30.2 domain (PRYSPRY) that is present in most members (Malinowska et al.). BTN1A1, along with BTN2A2, has been shown to inhibit the proliferation of CD4+ and CD8+ T cells, modify T cell metabolism, and affect the expression of IL-2 and IFN-γ (Smith et al.). Due to these modulatory effects on T cells, BTN1A1 may have a role in inhibiting the development of autoimmune diseases (Stefferl et al.). BTN1A1 is also expressed in mammary glands and is required for the secretion of milk lipids during lactation (Ogg et al.). This protein contains a His-residue tag at the carboxyl end of the polypeptide chain. For consistency and reproducibility across your applications, Serpin A12 from STEMCELL comes lyophilized with ≥ 92% purity, and is verified by LAL analysis to ensure endotoxin levels are ≤ 1.0 EU/μg protein.