Antibodies as Clinical Tools

Question 1

What is serum?

Answer 1

The fluid component of clotted blood

Question 2

What is antiserum?

Answer 2

Serum from an immunized individual

Question 3

What is serology?

Answer 3

The use of antibodies to detect and measure antigens using serological assays, named because they were originally performed using serum

Question 4

What is a titer?

Answer 4

A measure of the concentration of specific antibody in a sample, expressed in a ratio that represents how many times the sample can be diluted until no specific antibodies can be detected

Question 5

What are polyclonal antibodies?

Answer 5

Various antibodies specific for the same antigen but different epitopes within that antigen; made by various B cells

Question 6

What are monoclonal antibodies?

Answer 6

Antibodies specific for the same epitope on the same antigen

Question 7

How are monoclonal antibodies formed?

Answer 7

By a single normal B cell fusing with an immortal malignant B cell line forms B cell hybridoma

Question 8

Splenic B cells

Answer 8

normal B cells
mortal
express the enzyme 
        required to survive 
        in a special medium
        (selection medium)
express Igs

Question 9

Myeloma

Answer 9

malignant B cell line
immortal
deficient for an enzyme 
         required to survive in a 
         special medium
        (selection medium)
do not express Igs

Question 10

Clones (hybridomas)

Answer 10

each clone (hybridoma)
        expresses and secretes 
        antibody of single specificity
hybridomas are screened to 
        identify the ones producing
        antibody of desired specificity

Question 11

Fused cells (hybrids)

Answer 11

B cells provide the enzyme 
        the myeloma lacks
unfused B cells cannot 
        survive indefinitely
only immortalized hybrids
        survive in selection medium
hybrids are grown as 
        single-cell clones

Question 12

What is a primary antibody?

Answer 12

An antibody specific for a target antigen of interest such as a human protein

Question 13

Where are primary antibodies typically raised?

Answer 13

Animals

Question 14

What is a secondary antibody?

Answer 14

An antibody specific for a primary antibody

Question 15

Where are secondary antibodies raised?

Answer 15

In a species distinct from that of the primary antibody

Question 16

What is agglutination?

Answer 16

Clumping together of particles, usually by antibody molecules binding to antigens on the surface of adjacent particles

Question 17

What is hemagglutination?

Answer 17

Clumping together or red blood cells when antibodies bind cell surface antigens

Question 18

What is a precipitin reaction?

Answer 18

When sufficient quantities of antibody are mixed with soluble macromolecular antigens, a visible precipitate can form

Question 19

How can erythroblastosis fetalis occur?

Answer 19

If a Rh- mother is exposed to her fetuses Rh+ blood then her blood will for antibodies against the Rh factor and in subsequent pregnancies in which the fetus is Rh+ the mother’s IgG will cross the placenta and cause hemagglutination

Question 20

What test checks for maternal Rh antibodies?

Answer 20

Coombs test or antiglobulin test

Question 21

Explain the steps in the Direct Antibody Complex

Answer 21

Blood drawn and wash away the plasma to leave just the bound RBC anti human antibody complex. Antihuman globulin is added and binds to the complex causing agglutination

Question 22

Explain the steps in the Indirect Antibody Complex

Answer 22

Blood drawn and was out the RBC leaving just plasma with unbound anti human antibodies. Next RBC reagent specific for the antibodies in question are added. They form a complex and anti human Ig is added to bind to the complex and form agglutination.

Question 23

Immunohistochemistry (IHC) steps:

Answer 23

tissue sample removed from patient
sample is frozen or chemically preserved and then embedded in paraffin
thin sections are made and stained with an antibody specific for the protein of interest

Question 24

Immunocytochemistry (ICC) steps:

Answer 24

cells are stained with an antibody specific for the protein of interest
typical cell samples include blood smears, swabs, aspirates, or cells from a tissue sample after extracellular matrix and stromal components have been removed

Question 25

Fluorescence method of detection:

Answer 25

primary or secondary antibody is conjugated to a fluorophore that is observed by fluorescence microscopy

Question 26

Chromogenic method of detection:

Answer 26

primary or secondary antibody is conjugated to an enzyme that acts on a provided colorless substrate to produce a colored precipitate that is observed by light microscopy

Question 27

What are anti-nuclear antibodies?

Answer 27

Auto reactive antibodies against self DNA, RNA and proteins associated with nucleic acids

Question 28

Steps in an ANA (anti-nuclear antibody) test:

Answer 28

Draw blood keep just the serum. Add the serum to a glass plate covered in human cells with large nuclei (want large amounts of Nucleic Acid) then add labelled secondary anti human antibody and observe under a fluorescent microscope