Immunoassaya

Question 1

What forms when immune complexes precipitate in agarose?

Answer 1

precipitate line

Question 2

Immunodiffusion

Answer 2

poor sensitivity
non-quantitavtive
can’t be used with mixtures
place antibodies in one well and antigens in another and they diffuse towards each other, when they form a complex a precipitate line is seen on the gel

Question 3

immunoelectrophoresis

Answer 3

poor sensitivity
non-quantitative
pt serum and serum of “normal” pt pipetted in wells above and below a trough. Electrophoresis step to separate serum samples. Add rabbit anti-human antiserum to the trough and allow diffusion. Precipitate lines form.

Question 4

nephelometry

Answer 4

used to determine levels of IgM, IgG, and IgA from a serum sample

Question 5

antibody titer

Answer 5

the measurement of how much antigen-specific antibody is contained within an antibody sample. Titer is typically expressed as an endpoint titer which reflects the inverse of the last tested dilution that yields a positive result for antibody presence

Question 6

agglutination titer

Answer 6

highest dilution of a serum sample that causes clumping of microorganisms or other particulate antigens

Question 7

hemagluttination assay

Answer 7

can be used to identify RBC-specific antibodies in a patient’s serum, or they can be used in a more general way by complexing an antigen of interest to the surface of the RBC to use the RBCs as an indicator

• coombs
• indirect coombs

Question 8

Direct Coombs test (direct antiglobulin test/DAT)

Answer 8

performed to look for antibodies or complement proteins bound to the surface of RBCs collected directly from a patient
some autoimmune responses result in this
positive result is agglutination reaction
highly sensitive
quantitative

Question 9

Indirect Coombs (indirect antiglobulin test/IAT)

Answer 9

is routinely performed to cross-match blood (prior to blood transfusions) and for prenatal testing of pregnant women
positive result is hemagglutination reaction
highly sensitive
quantitative

Question 10

Monospot test

Answer 10

for Epstein Barr virus
detects antibodies that are known as heterophile antibodies. Heterophile antibodies are produced by people infected with EBV. These antibodies will agglutinate horse RBCs

Question 11

primary antibody

Answer 11

a test sample that may or may not contain antibodies that are specific for some antigen of interest

Question 12

secondary antibody

Answer 12

antibody that will be used to detect the primary antibody

Question 13

convalescent serum

Answer 13

serum from a patient that has recovered from an infection. Low levels of IgM and high IgG

Question 14

acute phase serum

Answer 14

serum collected from a patient that is actively infected with a pathogen. Higher concentration of IgM than IgG and also MBP and Creactive protein and fibrinogen present (low albumin)

Question 15

ELISA

Answer 15

The most common assay that is used to measure antibody responses
quantitative measure of antibody specificity
Need to know specificity to perform this

Question 16

Immunocap

Answer 16

essentially an ELISA that uses fluorescent enzyme-conjugated anti-human IgE to detect allergen-specific IgE in the serum of a patient
very sensitive bc low levels of IgE in blood

Question 17

RAST

Answer 17

old method of immunocap
determine which allergen(s) the patient has made an IgE response to
detection antibody (anti-human IgE) has been radiolabeled

Question 18

51Cr-release assays

Answer 18

the most commonly used assay to measure antigen-specific CTLs
measures the ability of T cells or NK cells to kill target cells

Question 19

western blot

Answer 19

purified Ag and/or Ab not required
sensitive
non-quantitative

Question 20

immunohistochemistry

Answer 20

can be used to visualize the location of specific antigens within a tissue or even a single cell
Antibodies that have been modified by covalently binding them to either fluorochromes or colloidal gold particles (among other reporter substances) can be used for these studies