The innate immune system, also known as non-specific immune system and first line of defense, comprises the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner. This means that the cells of the innate system recognize and respond to pathogens in a generic way, but unlike the adaptive immune system, it does not confer long-lasting or protective immunity to the host. Innate immune systems provide immediate defense against infection, and are found in all classes of plant and animal life.
The innate immune system is thought to constitute an evolutionarily older defense strategy, and is the dominant immune system found in plants, fungi, insects, and in primitive multicellular organisms.
The major functions of the vertebrate innate immune system include:
- Recruiting immune cells to sites of infection, through the production of chemical factors, including specialized chemical mediators, called cytokines.
- Activation of the complement cascade to identify bacteria, activate cells and to promote clearance of dead cells or antibody complexes.
- The identification and removal of foreign substances present in organs, tissues, the blood and lymph, by specialised white blood cells.
- Activation of the adaptive immune system through a process known as antigen presentation.
- Acting as a physical and chemical barrier to infectious agents.
Read more about Innate Immune System: Anatomical Barriers, Inflammation, Complement System, Cells of The Innate Immune Response, Other Vertebrate Mechanisms, Neural Regulation of Innate Immunity, Pathogen-specificity, Innate Immune Evasion
Famous quotes containing the words immune system, innate, immune and/or system:
“The moral immune system of this country has been weakened and attacked, and the AIDS virus is the perfect metaphor for it. The malignant neglect of the last twelve years has led to breakdown of our country’s immune system, environmentally, culturally, politically, spiritually and physically.”
—Barbra Streisand (b. 1942)
“In every one of us there are two ruling and directing principles, whose guidance we follow wherever they may lead; the one being an innate desire of pleasure; the other, an acquired judgment which aspires after excellence.”
—Socrates (469–399 B.C.)
“The moral immune system of this country has been weakened and attacked, and the AIDS virus is the perfect metaphor for it. The malignant neglect of the last twelve years has led to breakdown of our country’s immune system, environmentally, culturally, politically, spiritually and physically.”
—Barbra Streisand (b. 1942)
“Human beings are compelled to live within a lie, but they can be compelled to do so only because they are in fact capable of living in this way. Therefore not only does the system alienate humanity, but at the same time alienated humanity supports this system as its own involuntary masterplan, as a degenerate image of its own degeneration, as a record of people’s own failure as individuals.”
—Václav Havel (b. 1936)