memory B cell

(noun)

A B cell subtype formed following primary infection in which the cell recognizes a specific epitope.

Related Terms

Examples of memory B cell in the following topics:

  • Making Memory B Cells

    • Memory B cells are a B cell sub-type that are formed following primary infection.
    • Memory B cells are a B cell sub-type that are formed following a primary infection .
    • The rest persist as the memory cells that can survive for years, or even a lifetime.
    • The fact that all the cells of a single clone elaborate one (and only one) paratope, and that the memory cells survive for long periods, is what imparts a memory to the immune response.
    • B lymphocytes are the cells of the immune system that make antibodies to invading pathogens like viruses.

  • Immunological Memory

    • As B cells and T cells mature into effector cells, a subset of the naïve populations differentiates into B and T memory cells with the same antigen specificities .
    • Memory B cells that differentiate into plasma cells output ten to hundred-fold greater antibody amounts than were secreted during the primary response .
    • After initially binding an antigen to the B cell receptor (BCR), a B cell internalizes the antigen and presents it on MHC II.
    • As a result, memory B cells and plasma cells are made.
    • Describe the role of memory B and T cells in immulogical memory

  • Clonal Selection and B-Cell Differentiation

    • B cells primarily function to make antibodies against antigens, act as antigen-presenting cells (APCs), and eventually develop into memory B cells to provide long-term immunity.
    • For example, memory B cells that differentiate after an adaptive immune response are thought to undergo clonal selection so that antibodies produced by newer memory B cells have considerably higher binding affinities to their antigens.
    • This theory may explain why secondary immune responses from memory cells are so effective that repeated infections by the same pathogen are stopped before symptoms even develop.
    • Following the initial infection, random mutations during clonal selection could produce memory B cells that can more easily bind to antigens than can the original B cells.
    • T cell-dependent B cell activation, showing a TH2-cell (left), B cell (right), and several interaction molecules.

  • Maturation of B Cells

    • The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells (APCs), and eventually develop into memory B cells after activation by antigen interaction.
    • After activation, the cell proliferates and B memory cells would form to recognize the same antigen.
    • Once a B cell encounters its cognate antigen and receives an additional signal from a T helper cell, it can further differentiate into either plasma B cells or memory B cells.
    • A small minority survives as memory cells that can recognize only the same epitope.
    • With each cycle, the number of surviving memory cells increases.

  • Immunological Memory

    • Immunological memory refers to the ability of B and T cells to produce long-lived memory cells that defend against specific pathogens.
    • When B and T cells begin to replicate during an adaptive immune response, some offspring become long-lived memory cells.
    • Following an infection, long-term active memory is acquired by activation of B and T cells.
    • Memory cells derive from their parent B and T cells, and undergo clonal selection following infection, which increases antigen-binding affinity.
    • When B and T cells begin to replicate, some of the offspring that they produce will end up becoming long-lived memory cells.

  • Specific T-Cell Roles

    • T helper cells assist the maturation of B cells and memory B cells while activating cytotoxic T cells and macrophages.
    • Their primary functions include antigen presentation and activation of B cells, and activation of cytotoxic T cells and macrophages.
    • Memory T cells are a subset of antigen-specific T cells that persist long after an infection has resolved.
    • Memory T cells comprise two subtypes: central memory T cells (TCM cells) and effector memory T cells (TEM cells), which have different properties and release different cytokines.
    • Effector memory cells may be either CD4+ or CD8+, and produce either helper or cytotoxic T cells in a secondary immune response.

  • Types of Adaptive Immunity

    • The adaptive immune response is mediated by B and T cells and creates immunity memory.
    • Humoral immunity refers to the component of the adaptive immune response that is caused by B cells, antibodies, and type 2 helper T cells (Th2), as well as circulating mast cells and eosinophils to a lesser extent.
    • The B cells then rapidly produce a large number of antibodies that circulate through the body's plasma.
    • This process is the reason why memory B cells can cause hypersensitivity (allergy) formation, as circulating IgE from those memory cells will activate a rapid inflammatory and immune response.
    • This diagram of adaptive immunity indicates the flow from antigen to APC, MHC2, CD4+, T helper cells, B cells, antibodies, macrophages, and killer T cells.

  • Overview of Adaptive Immunity

    • The APC travels to a part of the body that contains immature T and B cells, such as a lymph node.
    • Memory B and T cells are formed after the infection ends.
    • When B cells and T cells are activated, some become memory cells.
    • Throughout the lifetime of an animal, these memory cells form a database of effective B and T lymphocytes.
    • Pathogens that undergo mutation often have different antigens than those known by memory B and T cells, meaning that different strains of the same pathogen can avoid the memory-enhanced immune response.

  • Lymphocytes

    • Subtype 2 helper T cells present antigens to B cells.
    • Memory T cells are created after an adaptive immune response subsides, retaining the presented antigen.
    • Plasma cell and long-lived B cells that are the main source of antibodies.
    • Regulatory B cells (B reg cells) are immunosuppresive B cells that secrete anti-inflammatory cytokines (such as IL-10) to inhibit autoimmune lymphocytes.
    • Memory B cells are dormant B cells with the same BCR as the B cell from which they differentiated.

  • Classes of T Cells

    • This activation results in the expansion of the antigen-specific lymphocyte pool and the differentiation of these cells into effector and memory cells.
    • Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
    • In response to antigenic stimulation, helper T cells (characterized by the expression of CD4 marker on their surface) secrete proteins called cytokines, whose function is to stimulate the proliferation and differentiation of the T cells themselves, as well as other cells, including B cells, macrophages, and other leukocytes.
    • Memory T cells are an expanded population of T cells specific for antigens that can respond rapidly to subsequent encounter with that antigen and differentiate into effector cell to eliminate the antigen.
    • Distinguish between: naive, effector (helper and cytotoxic), memory and regulatory T cells