Human CD4+ T Cells
CD4+ helper T cells oversee the actions of the human immune system. They are involved in activating and directing other immune cells, specifically: (1) determining B cell antibody class switching, (2) the activation and growth of cytotoxic T cells, and (3) maximizing bactericidal activity of phagocytes (i.e. macrophages). CD4+ helper T cells are isolated from leukopaks by either positive (POS) or negative selection (NS) using immunomagnetic cell separation procedures.