| 背景 | This is clone L243, a mouse IgG2a monoclonal that recognizes human HLA-DR, one of the classical MHC class II molecules. L243 is a long-established, widely characterized anti-HLA-DR clone that binds a conformational epitope on the assembled alpha/beta heterodimer, making it well suited to studies of antigen-presenting cell biology, HLA-DR expression, and MHC class II function. The antibody is validated across a broad application range including flow cytometry, Western blot, immunoprecipitation, blocking assays, CyTOF, and frozen-section IHC, supporting both phenotyping and functional/mechanistic work. Supplied research-grade with low endotoxin (<1 EU/mg; ultra-low <0.5 EU/mg options) and available in bulk milligram-to-gram quantities, it is intended for demanding in-vitro and functional research where lot-to-lot consistency and scale matter. Because the target is human, this reagent is oriented toward human cell and tissue systems (PBMCs, dendritic cells, B cells, monocytes, cell lines) rather than mouse in-vivo dosing models. For research use only (RUO); not for diagnostic or therapeutic use.
HLA-DR is a classical MHC class II molecule (encoded here by the DRA chain, P01903, and a DRB chain, P01911) expressed as an alpha/beta heterodimer on professional antigen-presenting cells including dendritic cells, B lymphocytes, macrophages/monocytes, and thymic epithelium, and inducibly on activated T cells and other cell types. Its physiological role is to present peptides derived from exogenous and endosomal proteins to CD4+ T helper cells via the T-cell receptor, a central step in initiating and shaping adaptive immunity. Peptide loading occurs in the endolysosomal MIIC compartment, facilitated by the invariant chain (CD74) and the HLA-DM chaperone. HLA-DR expression level is a widely used marker of APC activation and, on monocytes, an indicator of immune status; HLA-DR alleles are highly polymorphic and strongly linked to autoimmune disease susceptibility, transplantation matching, and drug hypersensitivity. The HLA-DR antigen is present on B-lymphocytes, activated T-lymphocytes and activated natural killer (NK) lymphocytes. This antigen is also expressed on monocytes, macrophages, human progenitor cells and B-cell lymphomas. |
|---|
