CD4 APC

The clone SK3, a mouse monoclonal antibody selectively binds with a 55-59kD type I transmembrane glycoprotein and a member of the immunoglobulin superfamily. CD4 contains four extracellular Ig-like domains (D1- D4). The epitope for SK3 is located within the D3 domain of the protein, which has a structure resembling an Ig variable domain. Expression of CD4 is observed in subsets of T lymphocytes, monocytes, macrophages, and dendritic cells. Through interaction of MHC-II, CD4 facilitates cell-cell interaction, thymic differentiation, and activation of downstream signaling cascades. HIV infection of T-cells is instigated through binding of HIV to CD4. Binding of SK3 antibody blocks HIV infection through CD4 and also blocks the mixed lymphocyte reaction (MLR).