Human Mobilized Peripheral Blood Leukopaks are collected from healthy IRB consented donors that are negative for HIV, HBV and HCV from our own collection center. Mobilized peripheral blood donors are injected with Granulocyte-Colony Stimulating Factor (G-CSF), which stimulates the bone marrow to produce hematopoietic stem cells and mobilizes them into the bloodstream, over a period of 3–5 days. Mobilized mononuclear cells are collected by one of our trained technicians using the Spectra Optia® Apheresis System one or two days post injection (1 bag collected per day).