Questions and Answers
The classical complement pathway is activated by:
All of the following are characteristics of complement components except:
All of the following are true of the recognition unit except:
Which is referred to as C3 convertase?
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Mannose-binding protein in the lectin pathway is most similar to which classical pathway component?
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Which of the following describes the role of properdin in the alternative pathway?
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Which best characterizes the membrane attack complex?
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All of the following represent functions of the complement system except:
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Which of the following is true of the amplification loop in complement activation?
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Factor H acts by competing with which of the following for the same binding site?
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A lack of CRI receptors on red blood cells would result in which of the following?
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A lack of CR2 on cell membranes would result in which of the following?
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Why is complement not activated with anti-Rh (D) antibodies?
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The CH50 test measures which of the following?
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Which of the following would be most effective in preventing bystander lysis of red blood cells?
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Decreased CH50 levels may be caused by:
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Study Notes
Complement Pathways
- Classical complement pathway activation occurs through antigen-antibody complexes.
- Mannose-binding protein in the lectin pathway functions similarly to Clq in the classical pathway.
Characteristics of Complement Components
- Contrary to some beliefs, complement components are not always present as active enzymes.
- The recognition unit does not activate Clq as an esterase.
C3 Convertase
- C3 convertase can be designated as C4b2a, C3bBb, or iC3Bb, indicating multiple forms exist.
Properdin and Membrane Attack Complex
- Properdin plays a crucial role in the alternative pathway by stabilizing C3/C5 convertase.
- The membrane attack complex (MAC) is characterized by C9 polymerizing to form a transmembrane channel.
Functions of the Complement System
- The complement system enhances the clearance of antigen-antibody complexes rather than decreases it.
- Amplification loops in complement activation involve multiple factors, highlighting the system's efficiency.
Binding Sites and Immune Complex Clearance
- Factor H competes with factor B for the same binding site, impacting complement activation.
- A lack of CRI receptors on red blood cells results in insufficient clearance of immune complexes by the spleen.
- Absence of CR2 on cell membranes can lead to decreased antibody production.
Anti-Rh Antibodies and Complement Activation
- The presence of anti-Rh (D) antibodies does not activate the complement system due to the spatial arrangement of Rh antigens on red blood cells.
CH50 Test
- The CH50 test assesses overall complement activity, providing insight into the complement system's functionality.
Prevention of Bystander Lysis
- Decay Accelerating Factor (DAF) is effective in preventing bystander lysis of red blood cells.
CH50 Levels
- Decreased CH50 levels can stem from various factors, indicating potential issues within the complement system.
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Test your knowledge of key concepts in immunology with these Chapter 6 flashcards. Each flashcard covers important definitions related to the classical complement pathway and its components. Perfect for students looking to reinforce their understanding of immune responses.
