American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What are plasma cells derived from?

1. T cells

2. B cells

3. Neutrophils

4. Macrophages

The correct answer is: B cells

Plasma cells are specialized effector B cells that produce and secrete large quantities of antibodies. They originate from B cells that have undergone activation and differentiation in response to an antigen. When B cells encounter their specific antigen, they can proliferate and differentiate into plasma cells, which are essential for the humoral immune response. In this process, the B cells undergo class switching and affinity maturation, a series of steps that enhance their ability to produce effective antibodies. Plasma cells are characterized by their large size, abundant cytoplasm, and extensive rough endoplasmic reticulum, which are indicative of their role in synthesizing high levels of antibodies. The other cell types listed have different roles in the immune system: T cells are primarily involved in cell-mediated immunity, neutrophils play key roles in the innate immune response, and macrophages are important for phagocytosis and antigen presentation. Thus, the origin of plasma cells solely from B cells emphasizes their specific function in adaptive immunity.