tolerance

Examples of tolerance in the following topics:

• Clonal Selection and Tolerance

  • The concept of central tolerance was proposed in 1959 as part of a general theory of immunity and tolerance.
  • It was hypothesized that it is the age of the lymphocyte that defines whether an antigen that is encountered will induce tolerance, with immature lymphocytes being tolerance sensitive.
  • Central tolerance is distinct from periphery tolerance in that it occurs while cells are still present in the primary lymphoid organs (thymus and bone-marrow), prior to export into the periphery.
  • Peripheral tolerance is generated after the cells reach the periphery.
  • Regulatory T cells can be considered both central tolerance and peripheral tolerance mechanisms, as they can be generated from self (or foreign)-reactive T cells in the thymus during T cell differentiation.

• Biofilms, Persisters, and Antibiotic Tolerance

  • Biofilms and persisters are bacterial communities responsible for chronic diseases and antibiotic tolerance.
  • Persisters are multidrug tolerant cells present in all bacterial populations.
  • Persisters are not mutants, but rather phenotypic variants of the wild-type that upon inoculation produce a culture with similar levels of tolerance.
  • Biofilms and persisters are the cause of multidrug tolerance.
  • Explain the role of biofilms and persisters in multidrug tolerance, distinguishing this from multidrug resistance

• Regulating Immune Tolerance

  • Immune tolerance of self and harmless antigens occurs by deleting B and T cells that recognize those antigens, often near mucosal surfaces.
  • The acquired ability to prevent an unnecessary or harmful immune response to a detected foreign substance known not to cause disease or to self-antigens is described as immune tolerance.
  • The primary mechanism for developing immune tolerance to self-antigens occurs during the selection for weakly, self-binding cells during T and B lymphocyte maturation.
  • Immune tolerance is especially well developed in the mucosa of the upper digestive system because of the tremendous number of foreign substances (such as food proteins) that APCs of the oral cavity, pharynx, and gastrointestinal mucosa encounter.
  • Immune tolerance is brought about by specialized APCs in the liver, lymph nodes, small intestine, and lung that present harmless antigens to a diverse population of regulatory T (Treg) cells: specialized lymphocytes that suppress local inflammation and inhibit the secretion of stimulatory immune factors.

• Osmoregulators and Osmoconformers

  • Aquatic organisms with various salt tolerances adapt to their environments through osmoregulation and osmoconformation.
  • Stenohaline organisms, such as goldfish, can tolerate only a relatively-narrow range of salinity.
  • These organisms, such as the salmon, are tolerant of a relatively-wide range of salinity.

• Louis XIV and the Huguenots

  • The Edict treated some, although not all, Protestants with tolerance and opened a path for secularism.
  • By his edict, Louis no longer tolerated Protestant groups, pastors, or churches to exist in France.
  • The three are similar both as outbursts of religious intolerance ending periods of relative tolerance and in their social and economic effects.
  • The experiment of religious toleration in Europe was effectively ended for the time being.
  • However, French society would sufficiently change by the time of Louis' descendant, Louis XVI, to welcome toleration in the form of the 1787 Edict of Versailles, also known as the Edict of Tolerance.

• Regulatory T Cells

  • The contribution of these populations to self-tolerance and immune homeostasis is less well defined.
  • An additional regulatory T cell subset, induced regulatory T cells, are also needed for tolerance and suppression.
  • Induced Regulatory T (iTreg) cells (CD4+CD25+Foxp3+) are suppressive cells involved in tolerance. iTreg cells have been shown to suppress T cell proliferation and experimental autoimmune diseases. iTreg cells develop from mature CD4+ conventional T cells outside of the thymus: a defining distinction between natural regulatory T (nTreg) cells and iTreg cells.
  • The contribution of nTreg cells versus iTreg cells in maintaining tolerance is unknown, but both are important.

• The Political Revolution

  • The American Enlightenment promoted ideas of individual liberty, republican government, and religious toleration.
  • Politically, the age is distinguished by an emphasis upon liberty, democracy, republicanism, and religious tolerance – culminating in the drafting of the United States Declaration of Independence and the U.S.
  • As Outram notes, the Enlightenment comprised "many different paths, varying in time and geography, to the common goals of progress, of tolerance, and the removal of abuses in Church and state. "

• Elimination Reactions

  • Once again, the tolerance of radical reactions for a variety of functional groups is demonstrated.

• Maryland

  • The Calvert family recruited Catholic aristocrats and Protestant settlers for Maryland, luring them with generous land grants and a policy of religious toleration.
  • In 1649, Maryland passed the Maryland Toleration Act, also known as the Act Concerning Religion, a law mandating religious tolerance for Christians.
  • Passed by the assembly of the Maryland colony, it was the first law requiring religious tolerance in the British North American colonies.
  • Although Maryland was an early pioneer of religious toleration in the English colonies, religious strife among Anglicans, Puritans, Catholics, and Quakers was common in the early years.
  • Full religious toleration would not be restored in Maryland until the American Revolution.

• Cell-Mediated Autoimmune Reactions

  • This reaction thereby overcomes the negative signals responsible for B cell self-tolerance without necessarily requiring loss of T cell self-tolerance.
  • Dendritic cells that are defective in apoptosis can lead to inappropriate systemic lymphocyte activation and consequent decline in self-tolerance.
  • DQ therefore is involved in recognizing common self-antigens and presenting those antigens to the immune system in order to develop tolerance from a very young age.
  • When tolerance to self proteins is lost, DQ may become involved in autoimmune disease.