BLD 434 - TOPIC 2 EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS
Complement (C)
a large family of small soluble proteins produced primarily by liver hepatocytes
Opsonin
a protein that acts as a tag by binding to a pathogen, inducing phagocytosis.
Anaphylatoxin
complement fragments C3a and C5a, which are produced during complement
activation, induce inflammation by recruiting fluid/inflammatory cells to sites of antigen
deposition.
Chemoattractant
soluble fragments C3a and C5a recruit phagocytosis and other effector cells from the
blood to the site of infection.
Complement fixation
being able to bind or fix complement C3b to the surface of a pathogen.
CR#
complement receptor that facilitates phagocytosis
What's the difference between opsonization and complement fixation?
Complement fixation is a form of opsonization by the innate immune system, which is
the coating of a pathogen with immune protein, facilitating phagocytosis.
, What is meant by the statement, "Complement works in a cascade fashion that
amplifies as it proceeds"
Complement proteins activate each other, and once activated, can cleave thousands of
times.
What's the major advantage that complement has compared to antibody in
tagging pathogens for disposal?
- complement is fast and antibody is slow
- complement attaches to the pathogen by covalent bond, whereas antibody binding is
irreversible
4 main functions of complement proteins
1. opsonization - complement fixation tagging pathogen for phagocytosis
2. anaphylatoxins - promote inflammation
3. MAC - form pore in cell causing it to lyse
4. Chemoattractant - C3a recruits phagocytes to site of infection
Classical pathway activation
activated by C1 complex binding to antibody/c-reactive protein on the pathogen surface,
cleaving C2 and C4 in the generation of C3/C5 convertases
Alternative pathway activation
- spontaneous hydrolysis of C3 or by C3b formed from other pathways
- iC3/C3b binds to factor B, making is susceptible to cleavage by factor D, forming
iC3Bb or C3bBb
Lectin pathway activation
WITH COMPLETE SOLUTIONS
Complement (C)
a large family of small soluble proteins produced primarily by liver hepatocytes
Opsonin
a protein that acts as a tag by binding to a pathogen, inducing phagocytosis.
Anaphylatoxin
complement fragments C3a and C5a, which are produced during complement
activation, induce inflammation by recruiting fluid/inflammatory cells to sites of antigen
deposition.
Chemoattractant
soluble fragments C3a and C5a recruit phagocytosis and other effector cells from the
blood to the site of infection.
Complement fixation
being able to bind or fix complement C3b to the surface of a pathogen.
CR#
complement receptor that facilitates phagocytosis
What's the difference between opsonization and complement fixation?
Complement fixation is a form of opsonization by the innate immune system, which is
the coating of a pathogen with immune protein, facilitating phagocytosis.
, What is meant by the statement, "Complement works in a cascade fashion that
amplifies as it proceeds"
Complement proteins activate each other, and once activated, can cleave thousands of
times.
What's the major advantage that complement has compared to antibody in
tagging pathogens for disposal?
- complement is fast and antibody is slow
- complement attaches to the pathogen by covalent bond, whereas antibody binding is
irreversible
4 main functions of complement proteins
1. opsonization - complement fixation tagging pathogen for phagocytosis
2. anaphylatoxins - promote inflammation
3. MAC - form pore in cell causing it to lyse
4. Chemoattractant - C3a recruits phagocytes to site of infection
Classical pathway activation
activated by C1 complex binding to antibody/c-reactive protein on the pathogen surface,
cleaving C2 and C4 in the generation of C3/C5 convertases
Alternative pathway activation
- spontaneous hydrolysis of C3 or by C3b formed from other pathways
- iC3/C3b binds to factor B, making is susceptible to cleavage by factor D, forming
iC3Bb or C3bBb
Lectin pathway activation
