Final answer:
The humoral immune response relies on B cells which produce antibodies that target pathogens. These B cells, when activated, differentiate into plasma cells to secrete antibodies. Other immune cells such as macrophages and cytotoxic T cells also contribute to the immune defense.
Step-by-step explanation:
The humoral immune response is primarily dependent on B cells (B lymphocytes). These cells are responsible for the production of antibodies upon exposure to pathogens. Unlike T cells which are involved in the cell-mediated immune response, B cells are crucial in the humoral immune response that targets pathogens in body fluids. During an immune reaction, B cells can differentiate into plasma cells, which are the cells that actually produce antibodies. These antibodies, also known as immunoglobulins, directly bind to antigens on the surface of pathogens such as viruses and bacteria, neutralizing them and marking them for destruction by other immune cells.
Phagocytic cells like macrophages can engulf pathogens and are also involved in promoting inflammation, while cytotoxic T cells work in concert with other immune response agents, such as natural killer cells and antigens, to destroy virally infected cells.