Recombinant HLA-E Fragment (aa 22-305) – a high-purity, functional fragment of the human HLA class I histocompatibility antigen, alpha chain E, encompassing the Ig-like C1-type domain. This product is ideal for investigating immune regulation, peptide presentation, and HLA-E-mediated signaling in natural killer (NK) and T cell responses.

HLA-E is a non-classical major histocompatibility class Ib molecule critical for immune self-nonself discrimination. In complex with beta-2-microglobulin, it binds self-peptides derived from classical MHC class I signal sequences, serving as a ligand for NK cell inhibitory receptors like KLRD1-KLRC1 to maintain self-tolerance. Under cellular stress or infection, HLA-E presents pathogen-derived peptides (e.g., from HIV, mycobacteria, or SARS-CoV-2) to unconventional CD8-positive T cells, triggering antimicrobial responses. It also plays roles in viral immune evasion (e.g., by human cytomegalovirus and HIV-1) and maternal-fetal tolerance. The full-length protein is primarily localized to the cell membrane as a single-pass type I protein, with a soluble form (sHLA-E) secreted into the extracellular space. The recombinant fragment (aa 22-305) includes the functional Ig-like C1-type domain, enabling focused studies on peptide binding and receptor interactions.