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Immunology 3 Exam – Questions With Correct Answers
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Immunology 3 Exam – Questions With Correct Answers
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Immunology 3 Exam – Questions With Correct AnswersWhich complement activation pathway uses antibodies? Right Ans -
classical
Which complement activation pathway begins with a naive/immature C3?
Right Ans - alternative
Which complement activation pathway involves innate immunity? Right
Ans - alternative
What are the 2 substrates of the lectin complement pathway? Right Ans -
MBL (mannose-binding lectin) & CHO (usually mannose)
Which complement pathway components play an important role in
anaphylaxes & allergies? Right Ans - C3a & C5a
(a ~ anaphylaxes/ allergies)
What is the end product of the complement pathway & what does it do?
Right Ans - MAC; it coats the pathogen for opsonization & introduces
transmembrane channels --> lysis
What are the substrates of the classical complement pathway? Right Ans -
Ab + Ag --> C1 complex (w/ serine protease)
What are the substrates of the alternative complement pathway? Right Ans
- pathogen + immature C3 (w/ thioester hydrolysis)
What is the MAC made up of? Right Ans - C5 through C9
What can inhibit C3 convertase? Right Ans - DAF
What is the complement system? Right Ans - a part of the immune system
that enhances (complements) the ability of antibodies & phagocytic cells to
clear pathogens from an organism; part of the innate immune system, but can
also be recruited by the adaptive immune system
,when stimulated, _______ in the complement system cleave specific proteins to
release _______ & initiate an amplifying cascade of further cleavages. The end
result of this complement activation/ complement fixation cascade is massive
_______ of the response and activation of the cell-killing _______ Right Ans -
proteases; cytokines; amplification; membrane attack complex
which antibodies start the classical complement pathway? Right Ans - IgM
& IgG
at what step do the 3 different complement activation pathways converge?
Right Ans - C3 convertase - where C3 & C5 proteins are being cleaved
(activated)
the complement system is a series of ~20 heat labile ______ synthesized in the
______ Right Ans - plasma proteins; liver
complement functions in a cascade to attack extracellular pathogens; they do
this via: Right Ans - - lysing bacteria
- opsonizing bacteria
- promoting inflammation
TRUE/ FALSE: the complement cascade is highly regulated Right Ans -
TRUE
TRUE/ FALSE: the complement cascade is highly specific Right Ans - FALSE
- (highly regulated; not specific)
TRUE/ FALSE: complement proteins are present in inactive forms in the
serum Right Ans - TRUE - (they're then triggered by 1 of the 3
mechanisms)
how are complement proteins triggered to enter the classical pathway?
Right Ans - activated by IgM or IgG binding to their surface
how are complement proteins triggered to enter the alternative pathway?
Right Ans - spontaneous activation in the blood or bacterial surfaces
how are complement proteins triggered to enter the lectin pathway? Right
Ans - activated by opsonins binding to bacterial cell surface
,TRUE/ FALSE: when complement proteins are cleaved during activation, the
larger fragment is designated "a" & the smaller fragment is "b" Right Ans -
FALSE - "a" is smaller, "b" is larger
in the classical pathway, which complement proteins are involved in the initial
cascade? Right Ans - C1 --> C4 --> C2 --> C3
in the classical pathway, which complement proteins are involved in the
opsonin? Right Ans - C3 --> C5 --> C6
in the classical pathway, which complement proteins are involved in the
membrane attack complex? Right Ans - C6 --> C7 --> C8 --> lots of C9
all pathways form a _______, which cleaves & activates ______ & ______; after this,
the pathways overlap & use the same proteins Right Ans - C3/C5
convertase; C3; C5
what is the end result of the classical pathway? Right Ans - peptide
mediators of inflammation, phagocyte recruitment
what is the end result of the alternative pathway? Right Ans - MAC, lysis of
certain pathogens & cells
what is the end result of the MB-lectin pathway? Right Ans - C3b binds to
complement receptors on phagocytes --> opsonization of pathogens -->
removal of immune complexes
the classical complement pathway initiates after an IgM or IgG molecule
attaches to the surface of _______ Right Ans - a bacterium or virus (antigen)
in the classical pathway, activated C1 can cleave ______, yielding ______, which
has no proteolytic activity, & ______, which binds covalently to the microbial
surface near C1 Right Ans - C4; C4a; C4b
in the classical pathway, C4b binds to ______, making it susceptible to cleavage
by C1; this yields _______ on the surface of the bacterium Right Ans - C2;
C4bC2a (C3/C5 convertase)
, what is C4bC2a? Right Ans - the C3/C5 convertase (in classical pthwy)
in the classical pathway, C4bC2a can cleave many molecules of _____, yielding
______ Right Ans - C3; C3a & C3b
in the classical pathway, does the C3b (lots of it) bind covalently or non-
covalently to the bacterial surface? Right Ans - covalently
what part of the complement cascade is going on when there is a lot of C3b
stuck to the surface of a microbe? Right Ans - opsonization
in the lectin pathway of complement activation, there are 2 major host-
derived serum proteins that bind to bacterial surfaces to start the cascade;
what are they? Right Ans - - mannose binding lectin (MBL)
- ficolins
what is MBL (mannose binding lectin)? Right Ans - binds to mannose
residues & several other sugars present on many pathogens, but not on
mammalian cells; it is also produced by the liver in low quantities that are
increased during an acute phase response
what are ficolins? Right Ans - a family of proteins that binds to
carbohydrate structures on bacterial & fungal cells to activate the cascade;
they are present at higher levels in serum; animals lacking an adaptive
immune response have larger families of ficolins to provide broader
recognition of pathogens
TRUE/ FALSE: MBL & ficolins both bind serine proteases that cleave C4 & C2
Right Ans - TRUE
TRUE/ FALSE: the end result of the classical pathway & alternative pathway is
the same Right Ans - TRUE - they are initiated differently, but end result is
the same
in the alternative pathway of complement activation, C3 can be _______
activated by bacterial cell surfaces or in plasma, forming C3b attached _______
to the surface Right Ans - spontaneously; covalently
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