Final answer:
Delayed type hypersensitivity is classified as Type IV hypersensitivity, which is a T-cell-mediated response that takes 24 to 72 hours to develop after exposure to an antigen.
Step-by-step explanation:
Delayed type hypersensitivity is classified as Type IV hypersensitivity. This kind of immunologic response involves T-cell-mediated reactions and does not involve antibody mediation as seen in the types I to III hypersensitivities. Type IV hypersensitivity is characterized by sensitization upon first antigen exposure, whereby subsequent exposure activates T cells that lead to recruitment and activation of macrophages, resulting in inflammation. This process typically takes 24 to 72 hours to develop, hence the term 'delayed'. Delayed type hypersensitivity, also known as Type IV hypersensitivity, is a cellular immune response. It is characterized by a delayed reaction that occurs 24 to 72 hours after exposure to an antigen. Sensitized T cells, specifically the Th1 class, secrete cytokines that recruit macrophages and other phagocytes to the site, leading to inflammation and tissue damage.