which of the following complement pathways is part of the innate immune system course hero

by Amy Green Published 2 years ago Updated 1 year ago 6 min read

What is innate immunity quizlet?

Innate immunity (natural, native, nonspecific) Basic resistance to disease that one is born with. No prompt needed to work. First line of defense.

What is the innate immune system?

INNATE IMMUNITY. Innate, or nonspecific, immunity is the defense system with which you were born. It protects you against all antigens. Innate immunity involves barriers that keep harmful materials from entering your body. These barriers form the first line of defense in the immune response.

What is the role of complement in the immune response?

Complement is a major component of innate immune system involved in defending against all the foreign pathogens through complement fragments that participate in opsonization, chemotaxis, and activation of leukocytes and through cytolysis by C5b-9 membrane attack complex.

Which complement system pathways are part of the innate immunity?

There are three pathways of complement activation: the classical pathway, which is triggered directly by pathogen or indirectly by antibody binding to the pathogen surface; the MB-lectin pathway; and the alternative pathway, which also provides an amplification loop for the other two pathways.

What are the 3 components of innate immunity?

The innate immune system can be categorized into three defense mechanisms: (1) physical barriers, (2) cellular components, and (3) humoral responses (15). As will be discussed, the functions of these defense mechanisms are highly conserved between fish and mammals.

What are examples of innate immunity quizlet?

List examples of chemical substances associated with innate immunity: lysozymes, phospholipase A (tears and saliva), histatins (saliva), acidic pH, andimicrobial peptides (alpha and beta defensins secreted by cells of skin, respiratory, and GI tract), surfactant proteins of the lungs.

What is the role of complement in the innate immune response quizlet?

As part of the innate immune system, complement acts immediately to start the process of removal and resolution of the problem. Complement works with the inflammatory cells of the innate immune system and those of adaptive or acquired immunity.

Is complement activation part of innate immunity?

Complement is a central part of the innate immunity that serves as a first line of defense against foreign and altered host cells (1). The complement system is composed of plasma proteins produced mainly by the liver or membrane proteins expressed on cell surface.

Which statement is true about innate immunity?

Which statement is true about innate immunity? Innate immunity is the first, and most general, mechanism of protection against pathogens.

Is complement pathway innate?

It is part of the innate immune system, which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system.

Is C4 alternative pathway?

As noted, C4 (mixture of C4A and C4B) participates in all three of the complement pathways (classical, alternative, and lectin); the alternative pathway is "triggered spontaneously," while the classical and lectin pathways are elicited in response to the recognition of particular microbes.

Is the alternative pathway innate or adaptive?

The alternative pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, a natural defense against infections.

What are the 5 components of the innate immune system?

The cellular components of innate immunity consist, amongst others, of NK cells, macrophages, granulocytes, eosinophils, and antigen presenting cells (dendritic cells).

How is the innate immune system activated?

The cells and molecules of innate immunity are rapidly activated by encounter with microbes or other “danger signals.” The rapidity of the response is essential because of the fast doubling time of typical bacteria.

What is difference between innate and acquired immunity?

Innate immunity is the inborn resistance against infections that an individual possesses right from birth due to his genetic or constitutional markup. Acquired immunity is the resistance to infecting foreign substances that an individual acquires or adapts during life. Prior exposure to the antigen is not required.

What cells are in the innate immune system?

The innate leukocytes include: natural killer cells, mast cells, eosinophils, basophils; and the phagocytic cells include macrophages, neutrophils, and dendritic cells, and function within the immune system by identifying and eliminating pathogens that might cause infection.

Summary

The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system, which is not adaptable and does not change during an individ…

History

In 1888, George Nuttall found that sheep blood serum had mild killing activity against the bacterium that causes anthrax. The killing activity disappeared when he heated the blood. In 1891, Hans Ernst August Buchner, noting the same property of blood in his experiments, named the killing property "alexin", which means "to ward off" in Greek. By 1894, several laboratories had demonstrated that serum from guinea pigs that had recovered from cholera killed the cholera bacterium in vitro. He…

Functions

Complement triggers the following immune functions:
1. Membrane attack – by rupturing the cell wall of bacteria. (Classical Complement Pathway)
2. Phagocytosis – by opsonizing antigens. C3b has most important opsonizing activity. (Alternative Complement Pathway)

Overview

Most of the proteins and glycoproteins that constitute the complement system are synthesized by hepatocytes. But significant amounts are also produced by tissue macrophages, blood monocytes, and epithelial cells of the genitourinary system and gastrointestinal tract. The three pathways of activation all generate homologous variants of the protease C3-convertase. The classical complemen…

Activation of complements by antigen-associated antibody

In the classical pathway, C1 binds with its C1q subunits to Fc fragments (made of CH2 region) of IgG or IgM, which has formed a complex with antigens. C4b and C3b are also able to bind to antigen-associated IgG or IgM, to its Fc portion.
Such immunoglobulin-mediated binding of the complement may be interpreted as that the complement uses the ability of the immunoglobulin to detect and bind to non-self antigens as it…

Regulation

The complement system has the potential to be extremely damaging to host tissues, meaning its activation must be tightly regulated. The complement system is regulated by complement control proteins, which are present at blood plasma and host cell membrane. Some complement control proteins are present on the membranes of self-cells preventing them from being targeted by complement. One example is CD59, also known as protectin, which inhibits C9 polymerization du…

Role in disease

It is thought that the complement system might play a role in many diseases with an immune component, such as Barraquer–Simons syndrome, asthma, lupus erythematosus, glomerulonephritis, various forms of arthritis, autoimmune heart disease, multiple sclerosis, inflammatory bowel disease, paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome and ischemia-reperfusion injuries, and rejection of transplanted organs.

Modulation by infections

Research has suggested that the complement system is manipulated during HIV/AIDS, in a way that further damages the body.