B cells

Definition

B cells, also known as B lymphocytes, are a type of white blood cell that play a crucial role in the adaptive immune response. They are responsible for the production of antibodies, which help neutralize and eliminate pathogens, and also assist in the activation of other immune cells.

5 Must Know Facts For Your Next Test

1. B cells develop and mature in the bone marrow, where they acquire unique antigen-specific receptors on their surface.
2. Upon encountering an antigen, B cells can differentiate into plasma cells, which secrete large amounts of antibodies, or memory B cells, which can rapidly respond to future exposures.
3. Antibodies produced by B cells can neutralize pathogens, opsonize them for phagocytosis, or activate the complement system to aid in their destruction.
4. B cells play a key role in the humoral immune response, which is distinct from the cell-mediated immune response carried out by T cells.
5. Biologic response modifiers, such as monoclonal antibodies, can target and manipulate B cell function to treat various diseases, including autoimmune disorders and cancer.

Review Questions

• Explain the role of B cells in the adaptive immune response.
  • B cells are a crucial component of the adaptive immune system. Upon encountering an antigen, B cells can differentiate into plasma cells that secrete large quantities of antibodies. These antibodies can neutralize pathogens, mark them for destruction by other immune cells, or activate the complement system to aid in their elimination. B cells also play a role in the activation and regulation of other immune cells, making them central to the overall adaptive immune response.
• Describe how biologic response modifiers can target B cells to treat disease.
  • Biologic response modifiers, such as monoclonal antibodies, can be designed to target and manipulate B cell function for therapeutic purposes. For example, in autoimmune disorders, monoclonal antibodies can be used to deplete or inhibit pathogenic B cells that produce autoantibodies, thereby reducing inflammation and tissue damage. In cancer, monoclonal antibodies can target B cell-specific antigens to selectively eliminate malignant B cells while sparing healthy cells. By modulating B cell activity, biologic response modifiers can be a powerful tool in the treatment of various diseases.
• Analyze the differences between the humoral and cell-mediated immune responses, and explain the unique role of B cells in the humoral response.
  • The adaptive immune response can be divided into two main branches: the humoral immune response and the cell-mediated immune response. The humoral immune response, which is mediated by B cells, is focused on the production of antibodies that can neutralize and eliminate extracellular pathogens and toxins. In contrast, the cell-mediated immune response, carried out by T cells, targets and destroys infected or cancerous cells directly. B cells play a central role in the humoral response by differentiating into plasma cells that secrete large quantities of pathogen-specific antibodies, as well as memory B cells that can rapidly respond to future exposures. This antibody-mediated defense is a crucial aspect of the adaptive immune system, complementing the cell-mediated response to provide comprehensive protection against a wide range of threats.

Related terms

Antibodies: Proteins produced by B cells that bind to specific antigens, neutralizing them or marking them for destruction by other immune cells.

Antigen: A molecule, typically from a pathogen, that triggers an immune response and is recognized by specific antibodies or receptors on immune cells.

Plasma Cells: Specialized B cells that have differentiated to produce large quantities of antibodies in response to an antigen.