Understanding Complement Pathways

What initiates the classical complement pathway?

• Release of cytokines from immune cells

• Binding of antibodies to antigens

• Activation by pathogen recognition

• Binding of complement proteins to cell membranes

Which proteins are involved in the alternative complement pathway?

• C1, C2, C4

• C5, C6, C7

• C3, factor B, factor D, properdin

• factor H, factor I

How does the lectin complement pathway differ from the classical pathway?

• The lectin pathway is antibody-independent and activated by lectins, while the classical pathway is antibody-dependent and activated by antibodies.

• The lectin pathway is activated by antibodies, while the classical pathway is not.

• The lectin pathway is slower than the classical pathway in response time.

• Both pathways require the presence of antibodies to be activated.

What is the role of C3 convertase in the complement system?

• C3 convertase directly destroys pathogens without cleaving C3.

• C3 convertase is responsible for producing antibodies.

• C3 convertase cleaves C3, playing a key role in opsonization and activation of the complement system.

• C3 convertase inhibits the activation of the complement system.

How do complement proteins enhance phagocytosis?

• Complement proteins enhance phagocytosis by opsonization, marking pathogens for easier recognition and engulfment by phagocytes.

• Complement proteins provide energy to phagocytes for their function.

• They inhibit the activity of phagocytes to prevent overreaction.

• Complement proteins directly destroy pathogens by lysis.

Describe the importance of the alternative complement pathway in innate immunity.

• The pathway is responsible for producing red blood cells.

• The alternative complement pathway is primarily involved in adaptive immunity.

• It only functions in the presence of antibodies.

• The alternative complement pathway enhances innate immunity by rapidly opsonizing pathogens, promoting inflammation, and directly lysing pathogens.

What is the function of the lectin pathway in the immune response?

• The lectin pathway helps in the production of antibodies.

• The lectin pathway functions to activate the complement system in response to carbohydrate patterns on pathogens.

• The lectin pathway is involved in the activation of T cells.

• The lectin pathway directly destroys pathogens by phagocytosis.

How do complement proteins contribute to inflammation?

• Complement proteins have no effect on blood vessel permeability during inflammation.

• Complement proteins reduce inflammation by inhibiting immune cell activity.

• Complement proteins solely function to destroy pathogens without influencing inflammation.

• Complement proteins enhance inflammation by promoting immune cell recruitment and increasing blood vessel permeability.

What are the potential consequences of complement system dysregulation?

• Decreased risk of allergies

• Potential consequences include autoimmune diseases, increased infection risk, and chronic inflammation.

• Enhanced tissue repair

• Improved immune response

What triggers the activation of the lectin pathway in the complement system?

• Binding of lectins to specific carbohydrate patterns on pathogens.

• Release of histamines from mast cells.

• Interaction of antibodies with complement proteins.

• Direct recognition of pathogens by T cells.