What type of immune response is characterized by the rapid proliferation of cells upon second exposure to an antigen?

The secondary response is characterized by the rapid proliferation of B and T cells upon a second exposure to an antigen. This phenomenon occurs due to the presence of memory cells, which are formed after the first exposure during the primary immune response. These memory cells remain in the body for extended periods and enable the immune system to recognize and respond more swiftly and effectively upon subsequent encounters with the same antigen.

During the primary response, the immune system takes longer to identify the antigen and generate an adequate response, as it involves the activation of naïve cells. In contrast, the secondary response occurs more quickly and robustly, often resulting in a higher quantity of antibodies and activated T cells than what was initially produced. This enhanced efficiency is a fundamental aspect of the adaptive immune system, ensuring long-term protection against specific pathogens.

The other types of responses, such as the primary response and innate response, do not exhibit this characteristic rapid proliferation upon re-exposure. The tertiary response is a less commonly referenced term and typically refers to additional exposures, which does not have the same specific connotation in immunology as the secondary response.