CD200R3, Mouse, mAb Ba103

The monoclonal antibody Ba103 recognizes mouse CD200 Receptor-like 3 (CD200R3), a protein of ~38
kDa or ~74 kDa (reduced or non-reduced condition, respectively). CD200R3 presumably exists as a
disulfide-linked dimer on the cell surface, it is a single-pass type I membrane protein.
The OX-2, or CD200 receptor (CD200R), belongs to the immunoglobulin superfamily. CD200R contains
two Ig-like extracellular domains, one Ig-like C2-type (immunoglobulin-like) domain and one Ig-like V-type
(immunoglobulin-like) domain. and mediates inhibitory signals in myeloid cells. Mice deficient for the
ligand CD200 develop enhanced experimental allergic encephalomyelitis and collagen-induced arthritis.
Unlike CD200R, the CD200R-like receptors function as activating receptors. They contain short
cytoplasmic tails and a lysine residue in the transmembrane region and are likely to signal via adaptor
proteins such as DAP12, DAP10, FcRg, or CD3z.
CD200R3 is expressed in uterus and bone marrow-derived mast cells (at protein level). It is expressed in
uterus, spleen, bone marrow-derived dendritic, basophil and mast cells. CD200R3 is also expressed in
the lung of N. brasiliensis-infected mice. It is weakly expressed in brain, testis, lung and thymus.
CD200R3 is expressed preferentially on cells of the myeloid lineage, including mast cells and basophils.
Both cell types are involved in the host defense system against pathogens and in the development of
allergic disorders. They function as independent essential initiators of allergic reactions. Basophils are the
least common leukocytes in the peripheral blood accounting approximately 0.5 % of all leukocytes. In vivo
depletion of basophils by using monoclonal antibody Ba103 proved the essential role of basophils in the
development and maintenance of IgE-mediated chronic allergic inflammation.
The activating CD200 receptors, like CD200R3, play an important role in IgE-independent mast cell and
basophil activation. Monoclonal antibody Ba103 activates basophils ex vivo and elicits systemic
anaphylaxis when administered in vivo. Cross-linking of CD200R3 on MC/9 cells by monoclonal antibody
Ba103 induces degranulation. Furthermore, monoclonal antibody Ba103 is useful for depletion of
basophils.