secondary immune response

Examples of secondary immune response in the following topics:

• Immunological Memory

  • The adaptive immune system has a memory component that allows for a rapid and large response upon re-invasion of the same pathogen.
  • During the adaptive immune response to a pathogen that has not been encountered before, known as the primary immune response, plasma cells secreting antibodies and differentiated T cells increase, then plateau over time.
  • This is known as the secondary immune response.
  • The immune response to vaccination may not be perceived by the host as illness, but still confers immune memory.
  • Vaccines, often delivered by injection into the arm, result in a secondary immune response if the vaccinated individual is later exposed to that pathogen.

• Immunological Memory

  • When B and T cells begin to replicate during an adaptive immune response, some offspring become long-lived memory cells.
  • These memory cells remember all specific pathogens encountered during the animal's lifetime and can thus call forth a stronger response, called the secondary immune response, if the pathogen ever invades the body again.
  • Following reinfection, the secondary immune response typically eliminates the pathogen before symptoms of an infection can occur.
  • During the secondary immune response, memory T cells rapidly proliferate into active helper and cytotoxic T cells specific to that antigen, while memory B cells rapidly produce antibodies to neutralize the pathogen.
  • Many parasitic pathogens, such as the plasmodium protist that causes malaria, haven't successfully been vaccinated against because it is challenging to develop a vaccine that is strong enough to stimulate an immune response (sufficient immunogenicity) without causing a live infection.

• 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.
  • Secondary or peripheral lymphoid organs maintain mature naive lymphocytes until an adaptive immune response is initiated.
  • Mature lymphocytes ill then recirculate between the blood and peripheral lymphoid organs until they encounter the specific antigens where they perform their immune response functions.
  • Secondary lymphoid tissue provides the environment for the antigens to interact with the lymphocytes.

• Primary and Secondary Antibody Responses

  • Adaptive (or acquired) immunity creates immunological memory after an initial response to a specific pathogen, leading to an enhanced response to subsequent encounters with that same pathogen.
  • If a pathogen breaches these barriers, the innate immune system provides an immediate, but non-specific response.
  • If pathogens successfully evade the innate response, vertebrates possess a second layer of protection, the adaptive immune system, which is activated by the innate response.
  • Here, the immune system adapts its response during an infection to improve its recognition of the pathogen.
  • Generalize the role of the innate and adaptive immune system in regards to antibody response

• Active and Passive Humoral Immunity

  • The humoral immune response is the aspect of immunity mediated by secreted antibodies.
  • The humoral immune response (HIR) is the aspect of immunity mediated by secreted antibodies produced by B cells.
  • Active humoral immunity refers to any form of immunity that occurs as a result of the formation of an adaptive immune response from the body's own immune system.
  • Passive immunization is used when there is a high risk of infection and insufficient time for the body to develop its own immune response, or to reduce the symptoms of ongoing or immunosuppressive diseases.
  • This effect is usually overcome by secondary responses to booster immunization.

• Hypersensitivities

  • Maladaptive immune responses toward harmless foreign substances or self antigens that occur after tissue sensitization are termed hypersensitivities.
  • The immune reaction that results from immediate hypersensitivities, in which an antibody-mediated immune response occurs within minutes of exposure to a harmless antigen, is called an allergy.
  • Delayed hypersensitivity is a cell-mediated immune response that takes approximately one to two days after secondary exposure for a maximal reaction to be observed.
  • Most types of autoimmunity involve the humoral immune response.
  • On secondary exposure, the mast cells release histamines and other modulators that affect the symptoms of allergy.

• Immunodeficiencies

  • Most cases of immunodeficiency are acquired (secondary) but some people are born with a defective immune system, or primary immunodeficiency.
  • T-cell deficiency is often caused secondary disorders such as acquired immune deficiency syndrome.
  • Immunodeficiency often affects multiple components, with notable examples including severe combined immunodeficiency (which is primary) and acquired immune deficiency syndrome (which is secondary).
  • Distinctions between primary versus secondary immunodeficiencies are based, respectively, on whether the cause originates within the immune system itself or, in turn, is due to insufficiency of a supporting component of it, or an external decreasing factor of it.
  • HIV directly infects a small number of T helper cells, and also impairs other immune system responses indirectly.

• Secondary Immunodeficiency Diseases

  • Immunodeficiency (or immune deficiency) is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent.
  • Most cases of immunodeficiency are acquired ("secondary") but some people are born with defects in their immune system, or primary immunodeficiency.
  • Transplant patients take medications to suppress their immune system as an anti-rejection measure, as do some patients suffering from an over-active immune system.
  • Distinction between primary versus secondary immunodeficiencies are based on, respectively, whether the cause originates in the immune system itself or is, in turn, due to insufficiency of a supporting component of it or an external decreasing factor of it.
  • HIV directly infects a small number of T helper cells and also impairs other immune system responses indirectly.

• Tonsils

  • The tonsils are small masses of secondary lymphoid tissue located in the pharynx.
  • The tonsils primarily facilitate adaptive immune responses in the upper respiratory tract, one of the most common pathways for pathogen entry in the body.
  • The secondary lymphoid tissue within the tonsils functions like the same type of the tissue in lymph nodes.
  • Captured antigens are presented to B and T cells within the tonsil, then the B cells migrate to germinal centers within the tonsil as an adaptive immune response is initiated.
  • It does not appear to cause weakened immune function.

• Cells and Organs of the Immune System

  • The immune system includes primary lymphoid organs, secondary lymphatic tissues and various cells in the innate and adaptive immune systems.
  • The key primary lymphoid organs of the immune system include the thymus and bone marrow, as well as secondary lymphatic tissues including spleen, tonsils, lymph vessels, lymph nodes, adenoids, skin, and liver.
  • The lymphatic system has multiple interrelated functions including the transportation of white blood cells to and from the lymph nodes into the bones, and the transportation of antigen-presenting cells (such as dendritic cells) to the lymph nodes where an immune response is stimulated.
  • Mast cells reside in connective tissues and mucous membranes, and regulate the inflammatory response.
  • There are two major subtypes of T cells: the killer T cell, which kills cells that are infected with viruses (and other pathogens) or are otherwise damaged or dysfunctional, and the helper T cell, which regulates both innate and adaptive immune responses and helps determine which immune responses the body makes to a particular pathogen.