University of Central Florida (UCF) MCB2004C Microbiology for Health Professionals Practice Exam 4

The adaptive immune system is characterized by its ability to recognize specific pathogens and retain memory of those encounters for a more efficient response upon subsequent exposures. The two primary components that define the adaptive immune system are humoral and cell-mediated immunity.

Humoral immunity involves the production of antibodies by B cells. These antibodies circulate in the bloodstream and lymphatic system, targeting specific antigens found on pathogens, neutralizing them, and marking them for destruction by other immune cells.

Cell-mediated immunity, on the other hand, is primarily mediated by T cells, which do not recognize free-floating antigens but rather detect antigens presented on the surface of infected or abnormal cells. This component is crucial for targeting intracellular pathogens, such as viruses, and for managing the immune response against tumors.

This combination of humoral and cell-mediated immunity allows the adaptive immune system to effectively tackle a wide variety of pathogens and is essential for long-term immunity. Other options, while related to the immune response, either describe overlapping concepts or do not encompass the broad scope of the adaptive immune system's functions.