Th17 Cells Summon an Immune System Strike Against Cancer Helper T cell’s effect raises possibility of cellular therapy, vaccine development T cells are lymphocytes, a type of white blood cell produced by the thymus equipped with receptors that recognize and bind to antigens, pieces of invading organisms presented to the T cells by dendritic cells. The bound antigen converts the T cell to T helper cells that secrete signaling molecules called cytokines to launch an appropriate immune response …