What is the function of plasma cells?
a.To present foreign antigens to immune cells.
b.To directly attack foreign cells when foreign antigens are recognized.
c.To phagocytize cells with foreign antigens.
d.To produce immunoglobulins specific to foreign antigens presented by T helper cells.
The correct answer and explanation is:
The correct answer is d. To produce immunoglobulins specific to foreign antigens presented by T helper cells.
Plasma cells are a type of white blood cell derived from B lymphocytes (B cells), and they play a crucial role in the immune system’s response to infections. When a pathogen or foreign antigen enters the body, it is typically recognized by B cells, which then differentiate into plasma cells. These plasma cells are responsible for producing and secreting large amounts of antibodies, also known as immunoglobulins (Ig).
Antibodies are specialized proteins that can recognize and bind to specific antigens on the surface of pathogens like bacteria, viruses, or toxins. By binding to these antigens, antibodies help neutralize the pathogens or mark them for destruction by other immune cells. The specificity of these antibodies is determined by the unique structure of the antigen-binding site, which is tailored to recognize a specific pathogen.
The activation of B cells to become plasma cells often requires help from T helper cells. T helper cells are a subset of T lymphocytes that play a supportive role in the immune response by releasing cytokines, which help activate B cells. Once activated, B cells can undergo clonal expansion and differentiate into plasma cells, which then produce antibodies. These antibodies are released into the bloodstream, where they circulate and bind to the foreign antigens.
The role of plasma cells is critical in the adaptive immune response, particularly in the humoral immunity pathway, which is responsible for antibody-mediated defense. This function is distinct from other immune cell types, such as macrophages or T cells, which have different roles like phagocytosis and direct cell-mediated attack. The production of specific antibodies by plasma cells is essential for long-term immunity and is the basis for how vaccines work, as they train the immune system to produce antibodies against specific pathogens without causing illness.