What is the site of development of the B lymphocyte?
B cell development begins in the fetal liver and continues in the bone marrow throughout our lives. The mature B cell that moves into the periphery can be activated by antigen and become an antibody-secreting plasma cell or a memory B cell which will respond more quickly to a second exposure to antigen.
What are B lymphocytes responsible for?
B cells are at the centre of the adaptive humoral immune system and are responsible for mediating the production of antigen-specific immunoglobulin (Ig) directed against invasive pathogens (typically known as antibodies).
What is the lymphocyte development?
Lymphocyte development is a highly regulated process in which immature lymphoid progenitors are generated from HSCs and then mature through defined stages of differentiation. Common lymphoid progenitors (CLPs) are LMPP progeny that are primarily destined to generate B lymphocytes.
What is the site of the development of the B lymphocyte from a stem cell in humans?
B lineage cells develop from hematopoietic stem cells (HSCs) in adult bone marrow (BM) through several well-characterized stages before migrating to secondary lymphoid tissues such as a spleen and lymph nodes.
Where are B lymphocytes found?
B lymphocytes can be found in primary lymphoid tissues, such as the bone marrow and ileal Peyer’s patches (a primary lymphoid tissue in some species because it is the site of B lymphocyte development, rather than the bone marrow), and in secondary lymphoid tissues, such as the spleen, lymph nodes, tonsils, and Peyer’s …
What are the two main functions of B cells?
The main functions of B cells are:
- to make antibodies against antigens,
- to perform the role of antigen-presenting cells (APCs),
- to develop into memory B cells after activation by antigen interaction.
How are B lymphocytes activated?
B cells are activated when their B cell receptor (BCR) binds to either soluble or membrane bound antigen. This activates the BCR to form microclusters and trigger downstream signalling cascades. Cytokines produced by T cells and other cells are important in determining what isotype the B cells express.
What are the major goals of lymphocyte development?
What are the two major goals of lymphocyte development? Answer: The two goals are (1) to ensure that all T cells have functional TCR and that (2) autoreactive cells are deleted (self-tolerance in ensured).
What is the lifespan of lymphocytes?
Most lymphocytes are short-lived, with an average life span of a week to a few months, but a few live for years, providing a pool of long-lived T and B cells. These cells account for immunologic “memory,” a more rapid, vigorous response to a second encounter with the same antigen.
What are the stages of B cell development?
In the B cell lineage pathway, a common lymphoid progenitor cell gives rise to a B lymphocyte progenitor that then differentiates into a Pre-Pro B Cell, a Pro-B Cell, and a Pre-B cell prior to the generation of an immature B cell. These stages of B cell development are antigen-independent.
Where does B cell maturation occur?
The B Cell: B cells mature in the bone marrow or in the lymph node. Bone Marrow: Mature B cells express antibodies on their surface, which are specific for a particular antigen. The antibodies are expressed on the cell surface and are primarily IgM with some IgD.
What are the ordered steps of B lymphocyte development?
The ordered steps of B-lymphocyte development are marked by a rearrangement of the heavy chain first and then the light chain variable region genes of the Ig molecule. From a lymphoid progenitor, B lymphocytes mature following a sequence from pro-B → pre-B → immature B lymphocyte → mature B lymphocyte → plasma cell (see Figure 10-2 ).
What is the role of B lymphocytes in humoral immunity?
B lymphocytes are the effectors of humoral immunity, providing defense against pathogens through different functions including antibody production. B cells constitute approximately 15% of peripheral blood leukocytes and arise from hemopoietic stem cells in the bone marrow.
How are antigen-activated mature B lymphocytes differentiate?
In the antigen-dependent phase, antigen-activated mature B lymphocytes differentiate into IgM-secreting plasma cells or switch to another antibody isotype. Immunoglobulins can be generated against an almost unlimited number of antigenic determinants through the rearrangement of genes encoding the light chain and heavy chain components.
Where do B lymphocytes come from in the body?
This process begins from stem cells present in the bone marrow (BM) which, depending on the different stimuli received, will generate B lymphocytes. They are derived from the early lymphoid progenitor, which passes to the common lymphoid progenitor.