AEMCA Practice Exam

Which type of white blood cell is primarily responsible for adaptive immunity found in lymph nodes?

1. Phagocytes

2. B-cells

3. Neutrophils

4. Eosinophils

The correct answer is: B-cells

B-cells are a crucial component of adaptive immunity, which is the body’s targeted defense mechanism against specific pathogens. They reside primarily in lymph nodes, where they play a pivotal role in recognizing antigens, the unique markers found on pathogens. Upon encountering an antigen, B-cells can differentiate into plasma cells, which produce antibodies that neutralize or mark these pathogens for destruction. This adaptive response is characterized by its ability to remember past infections, leading to a faster and more efficient response upon re-exposure to the same pathogen. This memory aspect is fundamental to the effectiveness of vaccinations. In contrast to phagocytes, neutrophils, and eosinophils, which are primarily involved in the innate immune response that acts quickly to pathogens, B-cells are designed for long-term immune memory and specific targeting of pathogens, showcasing their vital role in adaptive immunity.