How does your immune system protect you from bubonic plague?
Bubonic plague is a bacterial infection typically transmitted by fleas that have fed on infected rodents. Here's how your immune system protects you from this disease:
- Initial Encounter: When the plague bacteria (Yersinia pestis) enters your body through a flea bite, local skin cells at the site of infection release chemical signals that attract various immune cells.
- Phagocytes and Inflammation: Phagocytes, including macrophages and neutrophils, engulf and kill the bacteria. This process causes inflammation, leading to symptoms such as swelling, redness, and pain.
- Adaptive Immune Response: The initial inflammatory response triggers the adaptive immune response. Special antigen-presenting cells process and transport antigens (pieces of the plague bacteria) to lymph nodes.
- Activation of T Cells: In the lymph nodes, T cells recognize the antigens presented by the antigen-presenting cells. This activates both cytotoxic T cells (which kill infected cells directly) and helper T cells. Helper T cells secrete cytokines that activate other immune cells and stimulate B cells to produce antibodies.
- Antibody Production: B cells recognize the plague bacteria or bacterial fragments and differentiate into plasma cells, which produce specific antibodies that target the plague bacteria.
- Neutralization and Opsonization: Antibodies can neutralize the plague bacteria directly by binding to them, preventing their attachment and entry into host cells. Additionally, antibodies can tag bacteria for destruction by phagocytes through a process called opsonization.
- Complement Activation: Some antibodies can activate the complement system, which is a cascade of immune proteins. Activation of the complement system can lead to the formation of pores on the bacterial surface, causing bacterial lysis (destruction) and increased phagocytosis.
- Memory Cell Formation: During the immune response, memory B cells and memory T cells are generated. These cells "remember" the specific pathogen, providing long-term immunity. If you encounter the plague bacteria in the future, your immune system can mount a faster and stronger response, potentially preventing severe illness.
Vaccination plays a crucial role in protecting against bubonic plague by stimulating the immune system without directly exposing individuals to the live bacteria. Vaccines work by introducing weakened or killed plague bacteria or specific antigens, which allows the body to develop protective immunity without the risk of developing the full-blown disease.