Hypersensitivity- any immune response against a foreign antigen exaggerated beyond the norm. example are: ? Type I immediate ? Type ii hypersensitive ? Type iii immune complex mediated ? Type iv delay or cell-mediated Type 1 immediate Hypersensitivity o Develop within seconds. Commonly called allergies. The antigens that stimulate it are called allergens. Occurs via two processes; o Sensitization upon initial exposure to an allergen.