B cells

Definition

B cells are a type of white blood cell that plays a critical role in the adaptive immune system by producing antibodies. These cells are responsible for recognizing specific antigens, such as pathogens, and generating an immune response that leads to the neutralization or destruction of these foreign invaders. By differentiating into plasma cells, B cells can produce large quantities of antibodies that help to protect the body from infections and provide long-term immunity.

5 Must Know Facts For Your Next Test

1. B cells originate from stem cells in the bone marrow and mature there before migrating to lymphoid tissues like the spleen and lymph nodes.
2. When a B cell encounters its specific antigen, it undergoes activation and proliferation, leading to the formation of a clone of identical B cells.
3. Memory B cells are generated during the primary immune response and provide long-term immunity by quickly responding to future infections by the same pathogen.
4. The process of antibody production by B cells is enhanced through interactions with helper T cells, which provide necessary signals for full activation.
5. B cells can also function as antigen-presenting cells, displaying processed antigens on their surface to activate T cells and further coordinate the immune response.

Review Questions

• How do B cells contribute to the immune response after encountering an antigen?
  • Upon encountering an antigen that matches its specific receptor, a B cell becomes activated and proliferates into a clone of identical cells. Some of these clones differentiate into plasma cells, which secrete large amounts of antibodies targeting the antigen. This antibody production is essential for neutralizing pathogens and marking them for destruction by other components of the immune system.
• Discuss the role of memory B cells in providing long-term immunity following an infection.
  • Memory B cells are formed during the initial immune response when B cells are activated by an antigen. These specialized cells remain in the body long after the infection has been cleared. If the same pathogen invades again, memory B cells can quickly recognize it and mount a rapid and robust antibody response, thereby providing long-term immunity against reinfection.
• Evaluate the significance of interactions between B cells and T helper cells in regulating antibody production.
  • The interaction between B cells and T helper cells is crucial for effective antibody production. When a B cell presents an antigen on its surface, it interacts with a specific T helper cell that recognizes this antigen. This interaction provides essential signals, such as cytokines, which stimulate B cell activation, proliferation, and differentiation into plasma cells. Without this collaboration, the humoral immune response would be significantly impaired, illustrating the interconnectedness of adaptive immunity.

Related terms

Antibodies: Proteins produced by B cells that specifically target and bind to antigens, marking them for destruction by other immune cells.

T cells: A type of lymphocyte that plays a central role in cell-mediated immunity and helps regulate the functions of other immune cells, including B cells.

Plasma cells: Differentiated B cells that secrete large amounts of antibodies into the bloodstream to combat specific pathogens.