BLD 434 QUIZ 1 EXAM QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS GRADED A++
Define the following terms [including what cell(s) the term applies to, as
appropriate]: C
complement, main first line defense against infection. a large family of small soluble
proteins produced primarily by liver hepatocytes. many of them are zymogens (inactive
enzymes) which are also serine proteases, and they activate each other in a cascade
fashion with amplification capability
Define the following terms [including what cell(s) the term applies to, as
appropriate]: opsonin
general name for antibodies and complement proteins that coat pathogens, thereby
facilitating their phagocytosis by neutrophils or macrophages carrying receptors for the
opsonin.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: anaphylatoxin
general name for complement fragments C3a and C5a, which are produced during
complement activation. they induce local inflammation, recruiting fluid and inflammatory
cells to sites of antigen deposition. in some circumstances. C3a and C5a can induce
anaphylactic reactions.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: chemoattractant
,a chemical agent that induces movement of chemotactic cells in the direction of its
highest concentration.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: complement fixation
Opsonization by C3b. C3b binding to a pathogen surface tagging the pathogen for
disposal by a phagocyte.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: CR#
complement receptors found on macrophages and other cells that bind to iC3b on
pathogen
What is the difference between opsonization and complement fixation?
C3b binding to pathogen surface is called "complement fixation". Complement fixation is
one form of opsonization (coating of pathogen with immune protein, facilitating
phagocytosis)
Explain what is meant by the following statement: "Complement works in a
cascade fashion that amplifies as it proceeds".
many complement proteins are zymogens which are in active serine proteases and they
activate each other in a cascade fashion with tremendous amplification capability
each enzyme can leave thousands of substrate in those thousands Cleve, thousands
etc.
, The alternative pathway gets activated by C3b formed by the cleavage of C3 from the
classical or lectin pathway
List the major advantage that complement has compared to antibody in tagging
pathogens for disposal
very early in an infection (fast) and does NOT require an antibody
Works with serum antibody to kill pathogens
Attaches to antigen with covalent bond
speed & amplification
List and define the 4 main functions that the complement proteins can perform
for the immune system
- anaphylatoxins
- opsonization
- chemotaxis
- direct lysis (MAC Complex)
Name the 3 separate pathways that can trigger complement activation and
identify the first complement component(s) that bind(s) to initiate each of these
pathways.
classical: IgG or IgM bound antibodies (C4 and C2) or C1qrs binding to a fixed antigen,
C reactive protein (CRP), or Pentraxin (PTX3)
lectin: mannose binding lectin, and MASP 1/-2 enzymes bound to a pathogen surface
alternative: spontaneous hydrolysis of C3 and Factor P (Properdin) C3b formed from
the classical or lectin pathway
COMPLETE SOLUTIONS GRADED A++
Define the following terms [including what cell(s) the term applies to, as
appropriate]: C
complement, main first line defense against infection. a large family of small soluble
proteins produced primarily by liver hepatocytes. many of them are zymogens (inactive
enzymes) which are also serine proteases, and they activate each other in a cascade
fashion with amplification capability
Define the following terms [including what cell(s) the term applies to, as
appropriate]: opsonin
general name for antibodies and complement proteins that coat pathogens, thereby
facilitating their phagocytosis by neutrophils or macrophages carrying receptors for the
opsonin.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: anaphylatoxin
general name for complement fragments C3a and C5a, which are produced during
complement activation. they induce local inflammation, recruiting fluid and inflammatory
cells to sites of antigen deposition. in some circumstances. C3a and C5a can induce
anaphylactic reactions.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: chemoattractant
,a chemical agent that induces movement of chemotactic cells in the direction of its
highest concentration.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: complement fixation
Opsonization by C3b. C3b binding to a pathogen surface tagging the pathogen for
disposal by a phagocyte.
Define the following terms [including what cell(s) the term applies to, as
appropriate]: CR#
complement receptors found on macrophages and other cells that bind to iC3b on
pathogen
What is the difference between opsonization and complement fixation?
C3b binding to pathogen surface is called "complement fixation". Complement fixation is
one form of opsonization (coating of pathogen with immune protein, facilitating
phagocytosis)
Explain what is meant by the following statement: "Complement works in a
cascade fashion that amplifies as it proceeds".
many complement proteins are zymogens which are in active serine proteases and they
activate each other in a cascade fashion with tremendous amplification capability
each enzyme can leave thousands of substrate in those thousands Cleve, thousands
etc.
, The alternative pathway gets activated by C3b formed by the cleavage of C3 from the
classical or lectin pathway
List the major advantage that complement has compared to antibody in tagging
pathogens for disposal
very early in an infection (fast) and does NOT require an antibody
Works with serum antibody to kill pathogens
Attaches to antigen with covalent bond
speed & amplification
List and define the 4 main functions that the complement proteins can perform
for the immune system
- anaphylatoxins
- opsonization
- chemotaxis
- direct lysis (MAC Complex)
Name the 3 separate pathways that can trigger complement activation and
identify the first complement component(s) that bind(s) to initiate each of these
pathways.
classical: IgG or IgM bound antibodies (C4 and C2) or C1qrs binding to a fixed antigen,
C reactive protein (CRP), or Pentraxin (PTX3)
lectin: mannose binding lectin, and MASP 1/-2 enzymes bound to a pathogen surface
alternative: spontaneous hydrolysis of C3 and Factor P (Properdin) C3b formed from
the classical or lectin pathway
