Cell Mediated Components of Adaptive Immunity & Allergy Flashcards
explain the The morphogenesis and roles of B- and
T-cells
Morphogenesis of B- and T-cells:
B- and T-cells are both derived from stem cells in the bone marrow. B-cells mature in the bone marrow and migrate to the spleen and lymph nodes. T-cells, on the other hand, mature in the thymus gland, which is located in the upper chest.
Roles of B-cells:
B-cells are responsible for producing antibodies, which are proteins that recognize and neutralize foreign substances in the body. When a B-cell encounters a foreign substance, it produces a specific antibody that binds to the foreign substance and marks it for destruction by other cells in the immune system. B-cells also have the ability to remember foreign substances they have encountered in the past, allowing for a faster and more efficient immune response upon future exposure.
Roles of T-cells:
T-cells have a variety of roles in the immune system. Some types of T-cells, called helper T-cells, help activate and coordinate other cells in the immune system, including B-cells. Other types of T-cells, called cytotoxic T-cells, directly attack and destroy cells that have been infected with a virus or other pathogen. T-cells also have the ability to recognize and destroy cancer cells and other abnormal cells in the body.
Concepts of clonal expansion and clonal
selection
Clonal expansion and clonal selection are two concepts related to the development and proliferation of immune cells.
Clonal expansion refers to the proliferation of a single clone of immune cells, which occurs when an antigen (a foreign substance such as a virus or bacterium) is recognized by a specific immune cell receptor. The activated immune cell undergoes repeated rounds of cell division, resulting in a large population of identical cells that are capable of recognizing and responding to the antigen.
Clonal selection, on the other hand, refers to the process by which specific immune cells are chosen for clonal expansion based on their ability to recognize and bind to an antigen. In this process, immune cells with receptors that are capable of binding to the antigen are selected for clonal expansion and proliferation, while those that cannot bind to the antigen are not selected.
The roles of T-cell receptors, MHC
proteins and cytokines in adaptive
immunity
T-cell receptors (TCRs), major histocompatibility complex (MHC) proteins, and cytokines play crucial roles in adaptive immunity.
T-cell receptors are proteins found on the surface of T cells, which are a type of white blood cell involved in the adaptive immune response. TCRs recognize specific antigens, such as those found on the surface of infected cells or cancer cells. When a TCR binds to an antigen, it triggers a series of events that activate the T cell and initiate an immune response.
MHC proteins are found on the surface of nearly all cells in the body, and they play a critical role in the presentation of antigens to T cells. MHC proteins bind to antigenic peptides, which are derived from intracellular proteins or foreign substances such as viruses or bacteria. The resulting complex of MHC protein and antigenic peptide is then displayed on the cell surface, where it can be recognized by T cells. There are two major classes of MHC proteins: MHC class I, which is expressed on all nucleated cells and presents intracellular antigens to CD8+ T cells, and MHC class II, which is expressed on antigen-presenting cells such as macrophages, dendritic cells, and B cells, and presents extracellular antigens to CD4+ T cells.
Cytokines are small proteins produced by immune cells that regulate the immune response. They can act as signaling molecules to attract immune cells to a site of infection or inflammation, stimulate the proliferation and differentiation of immune cells, or activate immune cells to release other cytokines or cytotoxic molecules. Cytokines also play a role in the regulation of the immune response by promoting or inhibiting the activation and differentiation of T cells and B cells.
In summary, T-cell receptors recognize specific antigens, MHC proteins present antigens to T cells, and cytokines regulate the immune response. These molecules are all critical components of the adaptive immune response, which allows the immune system to recognize and respond to a wide range of pathogens and foreign substances.
