B-Lymphocyte

Aka: B-Lymphocyte, B Cell, B-Cell Activation, B-Lymphocyte Surface Receptor, B-Cell Surface Receptor

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II. Definitions

  1. B-Lymphocyte (B Cell)
    1. B-Cells are responsible for Humoral Immunity
    2. B-Cells are named for where they were first found (Bursa of Fabricus in birds)
    3. Responsible for Antigen-specific Antibody (plasma cells) and secondary future responses (memory cells)

III. Physiology: General

  1. Derivation
    1. Fetal Liver
    2. Bone Marrow Pluripotent Stem Cells
  2. Peripheral Migration to Secondary Lymphoid Tissue
    1. Spleen
    2. Lymph Nodes
    3. Peyer's Patches (Small Bowel)

IV. Physiology: B-Cell Activation

  1. Images
    1. BCellActivation.jpg
  2. Recognition
    1. Antigen binds B-Lymphocyte Surface Receptor (BCR)
    2. BCR binding activates B-Lymphocyte
      1. T-Cell Independent Antigen (e.g. inert Antigens) alone activate B-Cells
        1. Signal 1
          1. B-Cell Surface Receptor (BCR) binding to Antigenic Epitopes (repeat Amino Acid sequences)
          2. Signal transduced from cell surface to into cell via Ig alpha and beta
        2. Signal 2
          1. B-Cell co-receptor complex associated CR2 binds Antigen-bound Complement C3d
      2. T-Cell Dependent Antigen (e.g. Microbes) require added stmulus (i.e. T Helper Cells)
        1. B-Cell Surface Receptor (BCR) binds Antigen AND
        2. B-Cells processes and presents Antigen to CD4+ T-Cells (T helper cells)
        3. CD4+ T-Cells (T helper cells) are activated by B-Cell surface Antigens and their co-stimulators
          1. Signal 1 for T-Cell Activation
            1. MHC Class 2 - Antigen Complex bind T-Cell Receptor (TCR)
          2. Signal 2 for T-Cell Activation
            1. Co-stimulators B7-1 and B7-2 bind the T-CellSurface CD28
        4. B Cell proliferation and differentiation is stimulated by T Helper Cell binding
          1. B-Cell CD40 surface Protein is bound by the Cytokine T Helper Cell CD40 Ligand
          2. Cytokines (IL2, IL4, IL5) are released by activated T-Helper Cells
  3. B-Cell Proliferation
    1. Activated Lymphocytes proliferate
  4. B-Cell Differentiation
    1. Plasma Cells (Antibody producing cells)
      1. Survive for days to weeks producing antibodies, and without replicating
      2. Primarily found in Lymph Nodes and Spleen
    2. Memory Cells
      1. Remain in B-Lymphocyte pool ready to respond to the same Antigen in future
      2. Future Antigen response is known as secondary immune response

V. Physiology: Plasticity

  1. Isotype Switching
    1. Antibody isotope type (e.g. IgE, IgG, IgM) are defined by the Antibody constant regions (C-Regions)
    2. The C-Regions may be abruptly modified to switch to production of a different Antibody isotope
      1. Example: A B-Cell may switch to IgE production in the case of Parasitic Infection
  2. Immunoglobulin Gene modifications in response to Antigen detection
    1. Antibodies contain hypervariable regions within the variable section (Fab Component)
    2. Hypervariable regions (complementarity-determining region or CDR)
      1. Three heavy chain hypervariable regions
      2. Three light chain hypervariable regions
    3. In response to infection, hypervariable region genes may be rearranged to respond specifically to the organisms
      1. Variations in variable and hypervariable genes result in increased production of organism specific Antibody

VI. References

  1. Guyton and Hall (2006) Medical Physiology, p. 419-50
  2. Mahmoudi (2014) Immunology Made Ridiculously Simple, MedMaster, Miami, FL

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Related Studies

Ontology: B-Lymphocytes (C0004561)

Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (CHV) White blood cells that make antibodies and are an important part of the immune system
Definition (NCI) Immunologically important lymphocyte that is not thymus-dependent, is either short-lived and naive or long-lived and of memory phenotype, and resembles the bursa-derived lymphocyte of birds in that it is responsible for the production of immunoglobulins.
Definition (NCI_NCI-GLOSS) A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B lymphocyte is a type of white blood cell.
Definition (MSH) Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
Definition (CSP) lymphoid cells concerned with humoral immunity; they are short lived cells resembling bursa derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
Concepts Cell (T025)
MSH D001402
SnomedCT 112130006
LNC LP15088-5, LP36861-0, MTHU002435, LA4275-9
English B-Cell, B-Cells, Bursa Dependent Lymphocytes, Bursa-Dependent Lymphocyte, Bursa-Dependent Lymphocytes, Lymphocyte, Bursa-Dependent, Lymphocytes, Bursa-Dependent, LYMPHOCYTES B, lymphocyte B cells, bursa-equivalent lymphocyte, lymphocyte B cells (lab test), B-lymphocyte, b-lymphocyte, b-lymphocytes, b cell, b lymphocyte, b cells, b-cell, b lymphocytes, b-cells, Lymphocytes B, B cells, B Cell Lymphocyte, B lymphocyte, B cell, B-cell, B lymphocyte (cell), B-Lymphocytes, B Cells, B Lymphocytes, B-Lymphocyte, B Cell
French Lymphocyte B, Cellules B, Lymphocytes B, Lymphocytes bursodépendants, Lymphocytes burso-dépendants, Ly B
Swedish B-lymfocyter
Czech B-lymfocyty
Finnish B-imusolut
Italian Cellule B, Linfociti bursa-dipendenti, Linfociti B
Russian B-KLETKI, LIMFOTSIT KOSTNOMOZGOVOI, B-LIMFOTSITY, B-КЛЕТКИ, B-ЛИМФОЦИТЫ, ЛИМФОЦИТ КОСТНОМОЗГОВОЙ
Japanese B細胞, Bリンパ球, Bリンパ細胞, ファブリキウス嚢依存性リンパ球, リンパ球-B, リンパ球-ファブリキウス嚢依存性, 嚢依存リンパ球
German LYMPHOZYTEN B, B-Lymphozyten, B-Zellen, Bursa-abhängige Lymphozyten
Croatian B-LIMFOCITI
Latvian B-šūnas, B-limfocīti
Polish Limfocyty B
Norwegian B-celler, Bursa-avhengige lymfocytter, B-lymfocytter
Spanish célula B, linfocito B (célula), linfocito B, Linfocitos B, Linfocitos Bursa-Dependientes, Células B
Dutch B-cellen, B-lymfocyt, B-lymfocyten, Bursa-afhankelijke lymfocyten, Lymfocyt, B-
Portuguese Células B, Linfócitos B, Linfócitos Bursa-Dependentes
Derived from the NIH UMLS (Unified Medical Language System)

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