WK13: Compliment Fixation Test Flashcards
(32 cards)
Person responsible for developing CFTs
Jules Bordet
discovered that when cholera bacteria were injected into the peritoneum of a guinea pig immunized against the infection, the pig would rapidly die
Richard Pfeiffer
True or False:
Bacteriolysis occurs when bacteria is injected into non-immunized guinea pig
False (did not occur - bacteriolysis occurs when the same animal received the antiserum from an immunized animal)
Antiserum loses its power to kill bacteria at ____ C
55C
bacteria-killing phenomenon was due to the combined action of two distinct substances: _____ and _____
antibody in the antiserum
Alexine (complement)
True or False:
When red cells were added to a normal serum mixed with a specific form of bacteria in a test tube, the bacteria remained active while the red cells were destroyed through the fixation of alexine
True
when serum containing the antibody specific to the bacteria was
destroyed, the alexine and the solution separated into a ________
layer of clear serum
Determines the presence of syphilis bacteria
Wasserman test
CFT is replaced with more direct, sensitive and rapid techniques such as
RIAs
EIAs
most common source of fresh complement
Guinea pig
complement can be preserved either by ______, _____ or _____
lipophilizing
freezing or
by adding
preservatives.
diluent for titration and CFT
Physiological saline with added magnesium and calcium ions
Complement fixation test consists of a ______ and ______ both of which can activate complement.
test system
indicator system
antibody to sheep red cells which is raised in rabbits
Haemolysin (amboceptors)
True or False:
If the serum contains specific, complement activating antibody the complement will be not be activated or fixed by the antigen-antibody complex
False (Activated and fixed by antigen-antibody complex)
True or False:
If there is no formation of ag-ab complex, complement will not be fixed
True
CFT: no hemolysis means that the test is _______
POSITIVE for the presence of Abs
CFT: when the complement remains, and the red blood cells are lysed in the indicator stage the CFT test is ______
NEGATIVE
step that detects whether complement has been utilized in the first step or not
STEP 2
In the 2nd step of CFT, an ________ is added
indicator system
True or False:
complement is fixed in the first step owing to the presence of antibody there will be no complement left to fix
to the indicator system.
True
If there is an antibody in the patient’s serum, there will be:
A. No antigen-antibody complex - complement will be present free or unfixed in the mixture
B. no complement left to fix to the indicator system.
A. No
antigen-antibody complex - complement will be present free or unfixed in the mixture
Advantages of CFT
Ability to screen against a large number of viral and bacterial infections at the same time, Economical
Disadvantages of CFT
• Not sensitive - cannot be used for immunity screening
• Time consuming and labor intensive
• Often non-specific (e.g. cross-reactivity between HSV and
VZV)
