Innate and adaptive immunity
Joint Event on Global Experts Meeting on STD-AIDS and Infectious Diseases & 12th International Conference on Allergy, Immunology and Rheumatology
November 21-22, 2019 | Singapore
Posters & Accepted Abstracts : J Infectious Disease Med Microbiol
Immunity is the capability of multicellular organisms to resist
harmful microorganisms from entering it. Immunity involves
both specific and nonspecific components. The nonspecific
components act as barriers or eliminators of a wide range
of pathogens irrespective of their antigenic make-up. Other
components of the immune system adapt themselves to
each new disease encountered and can generate pathogenspecific
immunity. An immune system may contain innate and
adaptive components. The innate system in mammalians,
for example, is composed of primitive marrow cells that are
programmed to recognise foreign substances and react. The
adaptive system is composed of more advanced lymphatic
cells that are programmed to recognise self-substances
and don't react. The reaction to foreign substances is
etymologically described as inflammation, meaning to set
on fire. The non-reaction to self-substances is described
as immunity, meaning to exempt or as immunotolerance.
These two components of the immune system create a dynamic biological environment where “health” can be seen as a physical state where the self is immunologically spared, and what is foreign is inflammatorily and immunologically eliminated. “Disease”can arise when what is foreign cannot be eliminated or what is self is not spared.
• Innate immunity, also called native immunity, exists by virtue of an organism’s constitution, that is its genetic make-up, without an external stimulation or a previous infection. It is divided into two types: (a) Non-Specific innate immunity, a degree of resistance to all infections in general. (b) Specific innate immunity, a resistance to a particular kind of microorganism only. As a result, some races, particular individuals or breeds in agriculture do not suffer from certain infectious diseases.
• Adaptive immunity can be sub-divided depending on how the immunity was introduced in 'naturally acquired' through chance contact with a disease-causing agent, whereas ‘artificially acquired immunity’ develops through deliberate actions such as vaccination. Both naturally and artificially acquired immunity can be further subdivided depending on whether the host built up immunity itself by antigen as‘active immunity’and lasts long-term, sometimes lifelong. ‘Passive immunity’is acquired through transfer (injection or infusion) of antibodies or activated T-cells from an immune host; it is short lived— usually lasting only a few months.
• Adaptive immunity can also be divided by the type of immune mediators involved; humoral immunity is the aspect of immunity that is mediated by secreted antibodies, whereas cell mediated immunity involves T-lymphocytes alone. Humoral immunity is called active when the organism generates its antibodies, and passive when antibodies are transferred between individuals or species. Similarly, cell-mediated immunity is active when the organisms’ T-cells are stimulated, and passive when T cells come from another organism.