1) dendritic cell show antigens to other cells in immune system (APCs) 2) interaction of an APC with a T helper cell 3) T cell releases cytokines (interleukins) activating other components of the immune system such as eosinophils and mast cells, triggering B lymphocytes to differentiate into plasma cells and started producing IgE antibodies. 4) antibodies then attach to mast cells and eosinophils.