CD4 (clone SK3) is a mouse monoclonal antibody that recognizes the human protein CD4. CD4 is a common marker of Helper T cells, and is a T cell coreceptor. All antibody conjugates have been validated in flow cytometry. Each is supplied at 5 uL/test, with sufficient antibody for either 25 (125uL) or 100 tests (500uL). The antibody belongs to the Biotium Choice list of select antibodies that have been validated and optimized in-house for optimal performance.