Complement System Quiz: Test Your Knowledge

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Questions and Answers

What is complement in the immune system?

A type of cytokine

A type of white blood cell

A humoral component (correct)

A type of T cell

Who discovered complement and what was his discovery?

Bordet, ability to kill bacteria (correct)

Koch, the ability to kill bacteria

Ehrlich, immune memory

Pasteur, antibody production

What is the difference between complement and factors in their designation?

Complement proteins have a letter, while factors have a number

Complement proteins have a name, while factors have a number

Complement proteins have a number, while factors have a name (correct)

Complement proteins have a number, while factors have a letter

What are the three pathways of complement activation?

The classical pathway, the alternative pathway, and the lytic pathway Signup and view all the answers

What is the function of C3b in the complement system?

Marking pathogens for destruction by phagocytic cells Signup and view all the answers

What is the role of C5a in the complement system?

Acting as a neutrophil activator and chemotactic factor Signup and view all the answers

How is the MAC complex inactivated in the fluid phase?

By protein S Signup and view all the answers

What can dysregulation of the complement system lead to?

Autoimmune disorders Signup and view all the answers

What is the lectin pathway activated by?

The binding of mannose binding lectin to mannose on a pathogen surface Signup and view all the answers

What is complement in the immune system?

A series of over 30 different proteins Signup and view all the answers

Which scientist discovered complement and what was his discovery?

Bordet discovered complement and its ability to kill bacteria. Signup and view all the answers

What are the functions of complement in the immune system?

Acting against pathogens Signup and view all the answers

What is complement fixation?

Utilization of complement by antigen-antibody complexes Signup and view all the answers

How many pathways of complement activation are there?

Three pathways Signup and view all the answers

What is the function of C3b in the complement system?

Marking pathogens for destruction by phagocytic cells Signup and view all the answers

What is the most potent anaphylatoxin produced in the complement system?

C5a Signup and view all the answers

What happens if the MAC complex binds to an autologous membrane?

It leads to lysis of self-cells Signup and view all the answers

What can dysregulation of the complement system lead to?

Various diseases including autoimmune disorders, infections, and inflammatory diseases Signup and view all the answers

Study Notes

Complement: a major component of the non-specific immune system

Complement is a humoral component of the non-specific immune system.
Complement was discovered by Bordet in 1894, who described its ability to kill bacteria as a lytic activity.
Complement is actually a complex series of over 30 different proteins that all play a role in the system.
Complement has many functions, including acting as opponents against pathogens and enhancing phagocytosis.
Complement contributes to the inflammation process and can result in anaphylaxis if not controlled.
Complement is involved in regulating antibody responses, clearing immune complexes, and clearing apoptotic cells.
Complement proteins are designated with a "C" followed by a number, while factors are designated with a name.
There are also lectins involved, such as Manos Binding Lectin (MBL), and complement receptors.
Complement activation is a cascade of events, similar to the coagulation cascade, where one component interacts with the next.
Complement fixation refers to the utilization of complement by antigen-antibody complexes, and is measured in hemolytic units.
Complement inactivation is the deactivation of a component of complement, resulting in the loss of hemolytic activity.
There are three pathways of complement activation: the classical pathway (antibody-dependent), the alternative pathway (antibody-independent), and the lectin pathway. All three converge at the activation of C3 and the generation of a C5 convertase, leading to the lytic pathway.Complement System: Classical, Lectin, and Alternative Pathways
The complement system is a series of proteins that work together to defend against pathogens.
The classical pathway is activated by antibodies binding to a pathogen.
The pathway forms a complex that cleaves C4 into C4a and C4b, and then cleaves C2 into C2a and C2b.
The C4b2a complex is a C3 convertase that cleaves C3 into C3a and C3b.
The C4b2a3b complex is a C5 convertase that ends the classical pathway.
Components of the pathway have biological activities, such as C2b causing edema and C3a activating basophils and mast cells.
The pathway is regulated by C1 inhibitor, C3 inactivator, and other factors that prevent overactivation.
Deficiencies in C1 inhibitor can lead to hereditary angioedema, causing localized edema but not anaphylaxis.
The lectin pathway is activated by the binding of mannose binding lectin to mannose on a pathogen surface.
The pathway forms a complex that cleaves C4 into C4a and C4b, and then cleaves C2 into C2a and C2b.
The C4b2a complex is a C3 convertase that cleaves C3 into C3a and C3b.
The alternative pathway is activated by the spontaneous hydrolysis of C3 into C3i, which can form a C3 convertase that cleaves C3 into C3a and C3b. The pathway is regulated by DAF and other factors to prevent excessive activation.Overview of the Complement System and its Regulatory Mechanisms
The complement system is a series of proteins that work together to defend the body against foreign invaders such as bacteria.
The system can be activated by three pathways - classical, lectin, and alternative - each of which leads to the formation of C3 convertases that cleave C3 into C3a and C3b.
C3b is an opsonin that binds to the surface of the pathogen and marks it for destruction by phagocytic cells.
The spontaneous breakdown of C3 generates C3b, which is regulated by factor H and I, and protects the body from self-destruction.
C3b that encounters an activator or protector membrane, without a regulator like DAF, becomes susceptible to factor P and generates C5 convertases, which lead to the formation of the membrane attack complex (MAC).
The MAC is a complex of C5b, C6, C7, C8, and multiple copies of C9 that creates a pore in the bacterial membrane, leading to its lysis and death.
C5a is also released in this pathway and plays a significant role in the system as a neutrophil activator, chemotactic factor, monocyte/macrophage activator, and mast cell/basophil degranulator.
C5a is the most potent anaphylatoxin produced in the complement system and is inactivated by carboxypeptidase.
The MAC complex is produced in the fluid phase and needs to bind to a membrane to be effective, but if it binds to an autologous membrane, it can result in lysis of self-cells.
Protein S inactivates the MAC complex in the fluid phase, while DAF and factor I inactivate C3b and C4b, respectively, to prevent self-destruction.
The complement system is tightly regulated by these mechanisms to protect the body from self-destruction and maintain homeostasis.
Dysregulation of the complement system can lead to various diseases, including autoimmune disorders, infections, and inflammatory diseases.

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Description

Test your knowledge of the complement system with this informative quiz. From its discovery to the different pathways of activation, this quiz covers the major components and functions of the complement system. Learn about the classical, lectin, and alternative pathways, and how they work together to defend the body against foreign invaders. Discover how the system is regulated to prevent self-destruction and maintain homeostasis. Take this quiz to see how much you know about this important component of the non-specific immune system.