lymphocyte

Examples of lymphocyte in the following topics:

• Lymphoid Cells

  • A lymphocyte is a type of white blood cell in the vertebrate immune system.
  • A lymphocyte is a type of white blood cell in the immune system.
  • Lymphocytes are vital for normal immune system function.
  • All lymphocytes originate from a common lymphoid progenitor cell known as a lymphoblast, before differentiating into their distinct lymphocyte types.
  • The formation of lymphocytes is known as lymphopoiesis.

• Lymphoid Tissue

  • Lymphoid tissue consists of many organs that play a role in the production and maturation of lymphocytes in the immune response.
  • The lymphoid tissue may be primary or secondary depending upon its stage of lymphocyte development and maturation.
  • Specialized lymphoid tissue supports proliferation and differentiation of lymphocytes.
  • Central or primary lymphoid organs generate lymphocytes from immature progenitor cells such as lymphoblasts.
  • Secondary lymphoid tissue provides the environment for the antigens to interact with the lymphocytes.

• Clonal Selection and T-Cell Differentiation

  • Clonal selection is an theory that attempts to explain why lymphocytes are able to respond to so many different types of antigens.
  • The theoretical basis of clonal selection is the assumption that lymphocytes bearing an antigen receptor for an antigen exist long before antigen presentation occurs, explained by the idea of random mutations (VDJ recombination) that occur during lymphocyte maturation.
  • It is also assumed that most lymphocytes never encounter the antigen for which they bear a receptor.
  • This assumes that random mutations resulted in lymphocytes that were autoreactive instead of reactive to non-self antigens.
  • Clonal selection of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce 2) immature lymphocytes with many different antigen receptors.

• Lymphocytes

  • A lymphocyte is a type of white blood cell in the vertebrate immune system.
  • A lymphocyte is a type of white blood cell in the immune system, including both the B and T cells of the adaptive immune system and natural killer (NK) cells of the innate immune system .
  • While these are the main categories of T lymphocytes, there are other subtypes within these categories as well as additional categories that are not fully understood.
  • Regulatory B cells (B reg cells) are immunosuppresive B cells that secrete anti-inflammatory cytokines (such as IL-10) to inhibit autoimmune lymphocytes.
  • A scanning electron microscope (SEM) image of a single human lymphocyte.

• Types of WBCs

  • Lymphocytes, which come in three types.
  • B-lymphocytes produce antibodies in the humoral immune response.
  • T-lymphocytes participate in the cell-mediated immune response.
  • B and T lymphocytes contain MHC antigen receptors and their activity is antigen-specific.
  • They phagocytize pathogens and present antigens to naive lymphocytes.

• Infectious Mononucleosis

  • The most commonly-used diagnostic criterion is the presence of 50% lymphocytes with at least 10% atypical lymphocytes (large, irregular nuclei), while the person also has fever, pharyngitis, and adenopathy.
  • The virus typically lives dormantly in B lymphocytes.

• Lymphomas

  • Lymphoma is cancer of the lymphocytes and and is treated with chemotherapy or radiotherapy.
  • Lymphoma is cancer of the lymphocytes, a type of cell that forms part of the immune system.
  • Lymphomas are closely related to lymphoid leukemias, which also originate in lymphocytes, but typically involve only circulating blood and bone marrow, and do not usually form static tumors (blood cells are generated in the bone marrow by a process termed haematopoesis).

• Thymus

  • The thymus is a specialized organ that "educates" T cells or T lymphocytes, which are part of the adaptive immune system.
  • It consists of primary lymphoid tissue, which provides a site for the generation and maturation of T lymphocytes, critical cells of the adaptive immune system.
  • Histologically, the thymus contains mature lymphocytes, immature lymphocytes, and stroma, while lobule tissues consist of an inner medulla and an outer cortex.
  • Autoimmune diseases occur when central tolerance is lost, which causes lymphocytes to recognize host molecules as antigens and attack them, even if those tissues otherwise function normally.

• Lymph Nodes

  • Lymph nodes are the primary site for antigen presentation and activation in adaptive immune response in B and T lymphocytes.
  • These lymphocytes are continuously recirculated through the lymph nodes and the bloodstream.
  • There, antigen-presenting cells called dendritic cells present the antigen molecule to naive B and T lymphocytes.
  • The lymph node is also arranged in such a way that the chance of B and T lymphocytes encountering dendritic cells is quite high, to facilitate antigen presentation.
  • Additionally, cancers like lymphomas that have tumors made out of aberrant lymphocytes nearly always show lymphadenopathy, often an early warning sign for this type of cancer.

• Natural Killer Cells

  • Natural killer (NK) cells are cytotoxic lymphocytes critical for the innate immune system.
  • Natural killer (NK) cells are cytotoxic lymphocytes critical to the innate immune system.
  • NK cells are large granular lymphocytes derived from the common lymphoid progenitor cells (lymphoblasts), which also generate B and T lymphocytes.