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  2. If and only if - Wikipedia

    en.wikipedia.org/wiki/If_and_only_if

    The corresponding logical symbols are "", "", [6] and , [10] and sometimes "iff".These are usually treated as equivalent. However, some texts of mathematical logic (particularly those on first-order logic, rather than propositional logic) make a distinction between these, in which the first, ↔, is used as a symbol in logic formulas, while ⇔ is used in reasoning about those logic formulas ...

  3. Allelic exclusion - Wikipedia

    en.wikipedia.org/wiki/Allelic_exclusion

    The variable domain of the B-cell antigen receptor is encoded by the V, (D), and J gene segments, the recombination of which gives rise to Ig gene allelic exclusion. V(D)J recombination occurs imprecisely, so that while transcripts from both alleles are expressed, only one is able to give rise to a functional surface antigen receptor.

  4. B cell - Wikipedia

    en.wikipedia.org/wiki/B_cell

    B cell activation occurs in the secondary lymphoid organs (SLOs), such as the spleen and lymph nodes. [1] After B cells mature in the bone marrow, they migrate through the blood to SLOs, which receive a constant supply of antigen through circulating lymph. [14] At the SLO, B cell activation begins when the B cell binds to an antigen via its BCR ...

  5. Logical biconditional - Wikipedia

    en.wikipedia.org/wiki/Logical_biconditional

    Venn diagram of (true part in red) In logic and mathematics, the logical biconditional, also known as material biconditional or equivalence or biimplication or bientailment, is the logical connective used to conjoin two statements and to form the statement "if and only if" (often abbreviated as "iff " [1]), where is known as the antecedent, and the consequent.

  6. Germinal center - Wikipedia

    en.wikipedia.org/wiki/Germinal_center

    Germinal centers or germinal centres (GCs) are transiently formed structures within B cell zone (follicles) in secondary lymphoid organs – lymph nodes, ileal Peyer's patches, and the spleen [1] – where mature B cells are activated, proliferate, differentiate, and mutate their antibody genes (through somatic hypermutation aimed at achieving higher affinity) during a normal immune response ...

  7. V (D)J recombination - Wikipedia

    en.wikipedia.org/wiki/V(D)J_recombination

    V(D)J recombination (variable–diversity–joining rearrangement) is the mechanism of somatic recombination that occurs only in developing lymphocytes during the early stages of T and B cell maturation. It results in the highly diverse repertoire of antibodies/immunoglobulins and T cell receptors (TCRs) found in B cells and T cells, respectively.

  8. Immunoglobulin class switching - Wikipedia

    en.wikipedia.org/wiki/Immunoglobulin_class_switching

    Mechanism of class-switch recombination that allows isotype switching in activated B cells. Immunoglobulin class switching, also known as isotype switching, isotypic commutation or class-switch recombination (CSR), is a biological mechanism that changes a B cell's production of immunoglobulin from one type to another, such as from the isotype IgM to the isotype IgG. [1]

  9. Memory B cell - Wikipedia

    en.wikipedia.org/wiki/Memory_B_cell

    IgE: Memory B cells that express IgE are very rare in healthy individuals. This may occur because B cells that express IgE more frequently differentiate into plasma cells rather than memory B cells [4] IgD only: Memory B cells that express IgD are very rare. B cells with only IgD are found concentrated in the tonsils. [3]