1. Phagocytosis:
* Neutrophils are the most abundant type of white blood cell. They engulf and destroy bacteria through phagocytosis. They use enzymes and other chemicals to break down the bacteria within their cells.
* Macrophages are larger and live longer than neutrophils. They also engulf and destroy bacteria, but they also play a role in presenting bacterial antigens to other immune cells, helping to initiate a more targeted immune response.
2. Antibody Production:
* B lymphocytes (B cells) produce antibodies that specifically bind to bacteria, marking them for destruction by other immune cells.
3. Direct Killing:
* Natural killer (NK) cells kill bacteria and other infected cells directly, without the need for prior sensitization.
4. Inflammation:
* White blood cells release chemicals that cause inflammation at the site of infection. This inflammation brings more white blood cells to the area, helps isolate the infection, and promotes healing.
5. Cytokine Production:
* White blood cells release cytokines, which are signaling molecules that help coordinate the immune response. They can activate other immune cells, attract more white blood cells to the area, and stimulate the production of more immune cells.
6. Antigen Presentation:
* White blood cells like macrophages and dendritic cells present bacterial antigens to other immune cells, such as T lymphocytes, helping to initiate a more specific and targeted immune response.
In summary: White blood cells play a crucial role in defending the body against bacterial infections through a combination of phagocytosis, antibody production, direct killing, inflammation, cytokine production, and antigen presentation.
