Designed to be used in conjunction with detailed texts on the subject, this chart provides an overview of the inner cellular workings of an allergic reaction. Walks though the 3 steps of the allergic reaction: the initial encounter, primed and activated. Provides visuals and definitions of allergens, Antigen Presenting Cell (APC), T-lymphocytes, cytokines, B-lymphocytes, IgE, basophils, eosinophils and mast cells. Size is 20" W by 26" H.