cellular immunity

Examples of cellular immunity in the following topics:

• 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.

• Classes of T Cells

  • T cells play a central role in cell-mediated immune response through the use of the surface T cell receptor to recognize peptide antigens.
  • Cellular immunity is mediated by T lymphocytes, also called T cells.
  • This type of immunity promotes the destruction of microbes residing in phagocytes, or the killing of infected cells to eliminate reservoirs of infection.
  • Another class of T cells called regulatory T cells function to inhibit immune response and resolve inflammation.
  • Their major role is to shut down T cell-mediated immunity toward the end of an immune reaction.

• Immunoassays for Disease

  • Immunology is the study of molecules, cells, and organs that make up the immune system.
  • When a foreign agent penetrates the first line of resistance, an immune reaction is elicited and immune cells are recruited into the site of infection to clear microorganisms and damaged cells by phagocytosis.
  • If the inflammation remains aggravated, antibody-mediated immune reaction is activated and different types of immune cells are engaged to resolve the disease.
  • The immune system is composed of cellular and humoral elements.
  • The cellular component includes mast cells, neutrophils, macrophages, T and B lymphocytes, and plasma cells.

• Tests That Differentiate Between T Cells and B cells

  • Lymphocytes are the only immunologically specific cellular components of the immune system.
  • They play a central role in cell-mediated immunity along with initiating rejection of foreign tissues following organ transplantation.
  • B-cells are also white blood cells and are a vital part of the humoral immunity branch of the adaptive immune system.

• Overview of the Immune System

  • Innate immune systems are found in all plants and animals.
  • It provides resistance through several physical, chemical, and cellular approaches.
  • Adaptive immunity is often sub-divided into two major types depending on how the immunity was introduced.
  • Both naturally and artificially acquired immunity can be further subdivided depending on whether immunity is induced in the host or passively transferred from an immune host.
  • 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.

• 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.
  • 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.
  • Radioimmunotherapy in turn involves the use of radioactively conjugated murine antibodies against cellular antigens, mostly for treatment of lymphomas.

• Treatment of Animal Viral Infections

  • Interferons play pivotal roles in shaping the immune responses in mammals.
  • This process occurs concomitantly with the inhibition of cellular protein synthesis, caused by the expression of viral proteases.
  • Both viral and cellular proteins are required for replication and transcription.
  • Interferons (IFNs) play pivotal roles in shaping the immune responses in mammals and are particularly important for the control of viral infections, cell growth, and immune regulation.
  • Elucidating the molecular and cellular biology of the virus-interferon interaction is key to understanding issues such as viral pathogenesis, latency, and the development of novel antivirals.

• Direct Damage

  • The phagocytes engulf invaders and present them to additional factors within the immune system that result in their destruction.
  • Pathogens that exhibit the ability to avoid contact utilize various processes to accomplish this, including: the ability to grow in regions of the body where phagocytes are incapable of reaching; the ability to inhibit the activation of an immune response; inhibiting and interfering with chemotaxis which drives the phagocytes to site of infection; and 'tricking' the immune system to identify the bacteria as 'self. ' Additional mechanism(s) by which bacteria can avoid destruction is by avoiding engulfment.
  • Once the pathogen has successfully evaded engulfment and destruction by the immune system, it is detrimental because the bacteria then multiply.
  • Often times, bacteria will directly attach themselves to host cells and utilize nutrients from the host cell for their own cellular processes.
  • Upon the use of host nutrients for its own cellular processes, the bacteria may also produce toxins or enzymes that will infiltrate and destroy the host cell.

• Cytokines and Chemokines

  • Cytokines and chemokines are both small proteins secreted by cells of the immune system.
  • The widespread distribution of cellular sources for cytokines may be a feature that differentiates them from hormones.
  • Some chemokines are considered pro-inflammatory and can be induced during an immune response to recruit cells of the immune system to a site of infection, while others are considered homeostatic and are involved in controlling the migration of cells during normal processes of tissue maintenance or development.

• Overview of Human-Microbial Reactions

  • Organisms expected to be found in the human microbiome may generally be categorized as bacteria (the majority), archaea, yeasts, and single-celled eukaryotes as well as various helminth parasites and viruses, such as those that infect cellular microbiome organisms.
  • The success of any pathogen depends on its ability to elude host immune responses.
  • Therefore, pathogens evolved several methods that allow them to successfully infect a host, while evading the immune system.
  • An evasion strategy used by several pathogens to avoid the innate immune system is to hide within the cells of their host.
  • The mechanisms used to evade the adaptive immune system are more complicated.