IMMUNOLOGY

Detailed explanation-1: -A type II hypersensitivity is said to occur when damage to the host tissues is caused by cellular lysis induced by the direct binding of antibody to cell surface antigens. While the antibodies involved in type I HS are of the IgE isotype, those involved in type II HS reactions are mainly of the IgM or IgG isotype.

Detailed explanation-2: -Type I hypersensitivity (also called immediate hypersensitivity) is due to aberrant production and activity of IgE against normally nonpathogenic antigens (commonly called allergens) (Fig. 7-4). Common antigenic allergens include animal dander, chemical additives, foods, insect stings, pollens, and even drugs.