Final answer:
In response to extracellular bacteria and fungi, the adaptive immune system primarily utilizes B cells, which, when stimulated by TH2 cells, differentiate and produce antibodies specific to these pathogens.
Step-by-step explanation:
For pathogens such as fungi and extracellular bacteria, the type of cell used in the adaptive immune response would be B cells. B cells, when stimulated by the TH2 pathway, differentiate into plasma cells, which secrete antibodies. These antibodies are specialized proteins that can recognize and neutralize extracellular pathogens. Helper T Lymphocytes, or TH cells, including both TH1 and TH2 cells, function to direct other immune cells.
In the context of extracellular pathogens, TH2 cells are particularly important as they stimulate B cells to become prolific antibody producers, a critical component of the adaptive immune response against these types of invaders.
Unlike TH1 cells that enhance the activities of macrophages and are associated with protection against intracellular pathogens, TH2 cells are responsible for activating B cells. This process involves the recognition of foreign antigens by B cell receptors (BCRs), presentation to TH2 cells, and subsequent activation and proliferation of the B cells through a process known as clonal selection. The result is a robust production of antibodies specific to the invading extracellular pathogen.