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Human peripheral Blood B Cells (HPBB) are the antibody forming cells of the immune system. They originate from pluripotent hematopoetic stem cells and differentiate in the fetal liver. In adults, B cells principally originate in the bone marrow. During differentiation, the diversity of antigen specificity among B cells is generated in an antigen-independent manner through the rearrangement of gene segments encoding parts of the variable region of the B cell receptor (BCR) for antigen, that is, immunoglobulin (Ig). The newly generated, surface Ig-expressing mature B cells leave the bone marrow and circulate into peripheral lymphoid organs. B cells are found in blood, lymph nodes, spleen and tonsil as well as other mucosal tissues. B cells comprise a majority of the bone marrow lymphocytes, but less than 1% of those in thymus. Non-activated B cells circulate through lymph nodes and spleen, in which they are clustered in follicles and marginal zones around the follicles.1
B cells can be activated to proliferate and to differentiate into antibody-secreting cells by encounter with antigens that bear epitopes complementary to their surface Ig. B cell responses to antigens can be classified into T cell dependent and T cell independent. Some antigens such as bacterial polysaccharides can induce vigorous B cell stimulation independently of T cells by strong cross-linking of the BCR. In contrast, efficient B cell responses to many protein antigens need an intimate interaction of B cells with helper T cells. Circulating B cells may interact with and be activated by T cells at extrafollicular sites, where T cells occur around small blood vessels in association with antigen-presenting dentritic cells. The activated T cell provides help to B cells in two forms: soluble mediators (cytokines) such as IL-4, IL-5, and IL-6, and membrane-bound stimulating molecules including CD40 ligand. Appropriately activated B cells enter the follicles, where they proliferate and displace resting cells, forming germinal centers. There they differentiate into plasma cells specialized for antibody production and long-lived memory B cells.2 Signal transduction by the BCR is critical for progression through B cell developmental checkpoints as well as for immune responses. Cross-linking of BCR leads to the activation of three types of intracellular protein tyrosine kinases (Lyn/Fyn/Blk, BTK and Syk). These tyrosine kinases then phosphorylate signaling components to activate a variety of signaling reactions, including phosphatidylinositol 4,5-bisphosphate hydrolysis, Ras activation, and phosphatidylinositol 3-kinase activation. Each of these signaling reactions, and also the signaling molecules Vav and HS1, appears to be important for at least some of the many types of B cell responses to antigen. The complexity of BCR signaling reactions may be required to allow the B cell to respond in a number of distinct ways to antigen (proliferation, survival, apoptosis, maturational arrest, etc.) depending on the maturation state of the B cell, the location in the body, the physical nature of the antigen, and the possible presence of the antigen in complex with antibody or complement components.3
Human Peripheral Blood B Cells (HPBB) should provide a useful tool for studying various aspects of pathology and biology of the human B lymphocytes in vitro. To meet various needs for research and development, Cell Applications, Inc. isolated and purified Human Peripheral Blood B Cells (HPBB) to create a more realistic in vitro model. Cell Applications' Human Peripheral Blood B Cells (HPBB) are isolated from the blood of healthy donors. They are cryopreserved immediately after isolation.
1. DeFranco, A.L.: Annu. Rev. Cell Biol. 3:143-178, 1987
2. Kishimoto, T. & Hirano, T.: Annu. Rev. Immunol. 6: 485-512, 1988
3. Kurosaki, T. et al: Annu. Rev. Immunol. 28:21–55, 2010
Characterization:
Each lot tested negative for HIV, Hepatitis B and Hepatitis C and negative for mycoplasma, bacteria, yeast, fungi.
Products are for research use only. They are not intended for human, animal, or diagnostic applications.
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Tissue:
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Normal human peripheral blood
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Cryopreserved ampoule:
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Immediately after isolation, 2,000,000 cells in DMEM containing 45% FBS & 10% DMSO.
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Kit contains:
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Ampoule of cryopreserved HPBB (6904-20a), 250 ml Blood Cell Maintenance Medium (615-250)
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Cells in flasks or multiwell plates:
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Shipped in Blood Cell Transfer Medium in either flasks or multiwell plates.
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Population doublings:
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Blood cells do no proliferate in culture
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