Final answer:
Mitosis is crucial for the immune response, allowing the rapid proliferation of specific B and T cells in a process called clonal expansion. This mitotic activity provides an efficient targeted attack against pathogens and establishes immunological memory, preparing the immune system for faster responses upon future encounters with the same pathogens.
Step-by-step explanation:
Role of Mitosis in an Immune Response
Mitosis plays a crucial role in the immune response, particularly in the processes of both humoral and cell-mediated immunity. When pathogens invade the body, B cells and T cells become activated to fend off the infection. During the immune response, a specific subset of B and T cells are selected based on the pathogen's antigens, a process known as clonal selection. This leads to clonal expansion, where these selected lymphocytes undergo rapid mitotic divisions to form a large number of identical cells capable of fighting the specific pathogen. The resulting army of B cells can turn into plasma cells that produce antibodies, while T cells can directly attack infected cells or help coordinate other parts of the immune system. Therefore, mitosis is vital for multiplying the specific lymphocytes that are required for a targeted attack against the invading pathogen, bolstering the immune response and establishing immunological memory for future protection.
Furthermore, under certain conditions, such as with intracellular pathogens like Mycobacterium tuberculosis, helper T cells (TH1 cells) activate macrophages to improve their ability to kill the pathogen. In addition, other types of cells, such as cytotoxic T cells, play a role in cell-mediated immunity by destroying virus-infected or cancerous cells. Again, these T cells proliferate through mitosis during the immune response. In the unfortunate case of cancers like leukemia, the cells that would normally aid the immune response become abnormal and may also undergo uncontrolled mitosis.
All these mechanisms guarantee that when the body encounters a pathogen, the immune system can rapidly expand the pool of cells that are equipped to neutralize the threat. Immunological memory is another aspect of the adaptive immune response where a subset of B and T cells become memory cells after their initial proliferation. These cells remain in the body, ready to divide and mount a swift response upon re-exposure to the same pathogen, demonstrating the involvement of mitosis in the long-term defense capabilities of the immune system.