What type of immune response is characterized by the formation of memory cells?

The adaptive immune response is characterized by the formation of memory cells. These memory cells are a crucial component of the adaptive immune system, developed after an initial encounter with a specific pathogen. When the immune system is exposed to a specific antigen, it mounts a response that includes the activation of lymphocytes, particularly B cells and T cells. Some of these activated cells differentiate into memory cells, which persist long after the initial infection has been cleared.

These memory cells enable the immune system to recognize and respond more swiftly and effectively to subsequent exposures to the same pathogen. This is the basis of immunological memory, which is why vaccinations are effective; they promote the formation of memory cells without causing disease. In contrast, the innate immune response operates in a non-specific manner and does not involve memory cells. The cell-mediated immune response is a component of the adaptive response that specifically targets infected or abnormal cells, but it still falls under the umbrella of the adaptive immune response as a whole. The autoimmune response is an abnormal response where the immune system attacks the body's own cells, which is not characterized by the formation of memory cells in a protective context.