Description: The monoclonal antibody OX104 recognizes human CD200 also known as OX2. CD200 is a member of the Ig superfamily with 2 Ig domains, a transmembrane and cytoplasmic domain. CD200 is expressed on resting and activated B cells, a subset of resting and activated T cells, keratinocytes, peripheral and central nerve cells, follicular dendritic cells and ovarian cells. The interaction with CD200R results in macrophage activation (IL-6 production), inhibition of mast cell degranulation along with reduced TNFα and IL-13 secretion and overall attenuation of the activation status of lymphocytes. A role has also been suggested in maternal tolerance as expression of CD200 is also present on the trophoblast.