Biological Systems MCAT Practice Exam

Which cells are primarily involved in adaptive immunity?

1. Natural Killer cells and Neutrophils

2. B cells and T cells

3. Monocytes and Macrophages

4. Bone marrow and Lymph nodes

The correct answer is: B cells and T cells

B cells and T cells are the main players in adaptive immunity, which is a specific and targeted immune response developed over time after exposure to pathogens. B cells are responsible for producing antibodies that neutralize pathogens and mark them for destruction. They can differentiate into plasma cells that secrete large volumes of antibodies, while also forming memory cells that provide long-lasting immunity. T cells, on the other hand, are crucial for cell-mediated immunity. They can directly kill infected cells (cytotoxic T cells) or help coordinate the immune response (helper T cells). The interaction between these two types of cells ensures a well-orchestrated response to specific antigens that the immune system encounters, leading to a highly efficient and robust defense against infections. In contrast, Natural Killer cells and Neutrophils are part of the innate immune response, which reacts quickly to pathogens but does not provide the specific targeting and memory characteristic of adaptive immunity. Monocytes and macrophages also function primarily in the innate immune response and play a role in phagocytosis and antigen presentation, but they are not the central components of adaptive immunity. Bone marrow and lymph nodes are organs involved in the development and activation of immune cells, but they are not themselves cells.