adaptive immunity

Examples of adaptive immunity in the following topics:

• Adaptive Immunity and the Immunoglobulin Superfamily

  • The defining characteristics of adaptive immunity are specificity for distinct molecules and an ability to "remember" and respond more vigorously to repeated exposures to the same microbe.
  • The components of adaptive immunity are lymphocytes and their products.
  • There are two types of adaptive immune responses: humoral immunity and cell-mediated immunity.
  • They are commonly associated with roles in the immune system.
  • Describe the role of immunoglobulins in the adaptive immune response, specifically in humoral immunity

• Primary and Secondary Antibody Responses

  • The immune system protects organisms from infection first with the innate immune system, then with adaptive immunity.
  • Pathogens can rapidly evolve and adapt to avoid detection and neutralization by the immune system.
  • Both innate and adaptive immunity depend on the ability of the immune system to distinguish between self and non-self molecules.
  • This type of immunity is both active and adaptive because the body's immune system prepares itself for future challenges.
  • Generalize the role of the innate and adaptive immune system in regards to antibody response

• 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.
  • Langerhans cells in the skin are part of the adaptive immune system.
  • These cells identify and eliminate pathogens and are important mediators in the activation of the adaptive immune system.
  • These cells serve as a link between the bodily tissues and the innate and adaptive immune systems, as they present antigen to T-cells, one of the key cell types of the adaptive immune system.
  • The cells of the adaptive immune system are special types of leukocytes, called lymphocytes .

• The Complement System

  • The serum complement system, which represents a chief component of innate immunity, not only participates in inflammation but also acts to enhance the adaptive immune response.
  • More recently, however, the role of the complement in the immune response has been expanded due to observations that link complement activation to adaptive immune responses.
  • It is now understood that the complement is a functional bridge between innate and adaptive immune responses that allows an integrated host defense to pathogenic challenges.
  • The finding that B lymphocytes bound C3 raised the question as early as in the 1970s as to whether the complement system was involved in adaptive immune responses.
  • Subsequent work demonstrated that depletion of C3 impaired humoral immune responses and provided direct evidence that efficient adaptive responses were contingent on an intact complement system in some cases.

• Antimicrobial Peptides

  • A first line of defense against pathogenic insult is called the innate immune system, which is followed by acquired immune responses associated with the activation of T and B cells aimed against specific antigens.
  • In contrast to the clonal, acquired adaptive immunity, endogenous peptide antibiotics or antimicrobial peptides provide a fast and energy-effective mechanism as front-line defense.
  • In addition to important antimicrobial properties, growing evidence indicates that AMPs alter the host immune response through receptor-dependent interactions.
  • AMPs have been shown to be important in such diverse functions as angiogenesis, wound healing, cytokine release, chemotaxis, and regulation of the adaptive immune system.

• Overview of the Immune System

  • Pathogens can rapidly evolve and adapt to avoid detection and neutralization by the immune system.
  • 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.
  • The immune system adapts its response during an infection in order to improve its recognition of the pathogen.
  • Both innate and adaptive immunity depend on the ability of the immune system to distinguish between self and non-self molecules, where self molecules are those components of an organism's body that can be distinguished from foreign substances by the immune system.
  • A further subdivision of adaptive immunity is characterized by the cells involved; humoral immunity is the aspect of immunity that is mediated by secreted antibodies, whereas the protection provided by cell-mediated immunity involves T lymphocytes alone.

• Natural Active Immunity

  • Naturally acquired active immunity occurs when a person is exposed to a live pathogen, develops the disease, and then develops immunity.
  • Immunity is the state of protection against infectious disease conferred either through an immune response generated by immunization or previous infection, or by other non-immunological factors.
  • Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response.
  • The adaptive immune response generated against the pathogen takes days or weeks to develop but may be long-lasting, or even lifelong.
  • The principle behind immunization is to introduce an antigen, derived from a disease-causing organism, that stimulates the immune system to develop protective immunity against that organism, but which does not itself cause the pathogenic effects of that organism.

• Superantigens

  • Superantigens (SAgs) are proteins that cause the T-cells of the immune system to over-react to infection.
  • The superantigens of each species are, like antigens, molecules the immune system recognizes as being foreign.
  • Superantigens cause symptoms of illness by tricking the T-cells of the immune system into over-reacting to these molecules.
  • Parts of a bacterium or a virus are usually recognized by the macrophage cells of the immune system.
  • This undermines one of the fundamental strengths of the adaptive immune system, that is, its ability to target antigens with high specificity.

• Type IV (Delayed Cell-Mediated) Reactions

  • Cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
  • Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or serum) and cellular immunity, for which the protective function of immunization was associated with cells.
  • Therefore in cell mediated immunity cytokines are not always present.
  • 3. stimulating cells to secrete a variety of cytokines that influence the function of other cells involved in adaptive immune responses and innate immune responses
  • Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells.

• Immunotherapy for Cancer

  • Cancer immunotherapy is the use of the body's own immune system to reject cancer.
  • Cancer immunotherapy is the use of the body's own immune system to reject cancer.
  • This can be either through immunization of the patient (e.g., by administering a cancer vaccine such as Dendreon's Provenge), in which case the patient's own immune system is trained to recognize tumor cells as targets to be destroyed, or through the administration of therapeutic antibodies as drugs, in which case the patient's immune system is recruited to destroy tumor cells by the therapeutic antibodies.
  • The injected immune cells are highly cytotoxic to the cancer cells and so help to fight them.
  • Antibodies are a key component of the adaptive immune response.