Antibodies in diagnostics

Question 1

What is a reporter

Answer 1

A way of determining if the antibody has bound to an antigen

Question 2

4 examples of a reporter

Answer 2

Enzymes
Fluorescent probes
Radioisotopes
Magnetic beads

Question 3

How do enzymes work as reporters

Answer 3

Antigens are washed over on an assay with antibodies that are attached to an enzyme. This is then washed over with a colourless substrate which can be converted to a coloured product porvided the antibody is antigen bound

Question 4

What is an anti-antibody

Answer 4

Antibodies produced against immunoglobulins of another species

Question 5

Uses of anti-anitbodies in diagnostics

Answer 5

Can be used for indirect labelling

Question 6

What is antisera

Answer 6

Serum that has had an antigen injected into and antibodies have been produced in response

Question 7

Original method of manufactured antibodies

Answer 7

Antisera

Question 8

How to make a monoclonal antidody

Answer 8

Take a normal B lymphocyte that is producing the antibody of interest and fuse it with a myeloma cell (tumour cell) giving you a hybridoma

Question 9

2 significant charactersitics of hybridomas

Answer 9

Can produce the specific antibody you want

Divide indefinetely as fused with tumour cell

Question 10

Producing antibodies via recombinant DNA

Answer 10

You isolate the genes encoding for the variable region of antibodies and introduce a varying set of specificities of antibodies to a bacteriophage population producing a library of phages with different specificity. Then screen a plate with a fixed antigen and any that dont stick will be washed off

Question 11

Uses of manufactured therapeutic antibodies

Answer 11

IV antibodies if cant make own
Anti-cancer therapy
Removal of t-cells from bone marrow grafts
Blocking cytokines

Question 12

-omab antibody nomenclature

Answer 12

Mouse

Question 13

-imab antibody nomenclature

Answer 13

Partly human

Question 14

-umab antibody nomenclature

Answer 14

Human

Question 15

Uses of manufactured diagnostic antibodies

Answer 15

Tissue typing
Blood group
Immunoassays
Immunodiagnosis

Question 16

What is ELISA

Answer 16

Enzyme linked ImmunoSorbent Assay

- used to measure levels of a particular molecules

Question 17

2 ways can have HIV antibodies without having HIV

Answer 17

• maternal antibodies

- clinical trials

Question 18

Will you have antibodies if very recently infected

Answer 18

No- process takes time

Question 19

Immunological concern of loss of appetite

Answer 19

Effect of poor nutrition on bone marrow cells

Question 20

What is an immune complex

Answer 20

Antibody bound to antigen

Question 21

What determines size of immune complex

Answer 21

Ratio of antigen bound to antibody

Question 22

What ratio gives rise to small immune complexes

Answer 22

Antigen>antibody

Question 23

What ratio gives rise to large immune complexes

Answer 23

Antibody>antigen

Question 24

Are small or larger immune complexes more easily cleared by immune system

Answer 24

Large as easily recognised

Question 25

Reason smaller immune complexes are less easily cleared

Answer 25

They dont effectively activate complement

Question 26

Particular problem with immune complexes in kidney

Answer 26

Glomerulonephritis

Question 27

Pathophysiology of glomerulonephritis

Answer 27

Small immune complexes pass through endothelium and get stuck in subendothelial layer where they can effectively activate complement- neutrophils release mediators which damage the basement membrane and cell membranes in glomerulus

Question 28

3 different things checked to determine immunodeficiency

Answer 28

• Serum immunoglobulin levels
• specfic antibodies
• lymphocyte subsets

Question 29

How to check serum Ig levels

Answer 29

Serum electrophoresis

ELISA

Question 30

How to check for specific antibodies

Answer 30

ELISA

Question 31

How to check for lymphocyte subsets

Answer 31

Flow cytometry

Question 32

What does serum elctrophoresis show in healthy person

Answer 32

A diffuse smear near top- is diffuse as many different antibodies with different charges

Question 33

What does smear at top of serum electrophoresis show

Answer 33

Gamma globulin region

Question 34

What does serum electrophoresis show in someone producing active immune response

Answer 34

A large, dark gamma globulin smear
Large as repsonse polyclonal
Dark as many antibodies

Question 35

What does serum electrophoresis show of someone with myeloma

Answer 35

Sharp single band

Small as monoclonal

Question 36

How does flow cytometry work to determine lymphocyte subpopulations

Answer 36

Specific lymphocytes express specific markers on cell surface which antibodies can be made against. These monoclonal antibodies have a fluorescent dye label- the cells are passed in stream through a laser beam which detects the fluorescense

Question 37

Natural history of HIV infection of someone without treatment

Answer 37

• Primary infection - CD4 will initially go down and then it will go up again after a few weeks
• The viral remains controlled by the immune system for some time (clinical latency)
• The viral load wont change that much during this time but CD4 will keep going down
• When the CD4 count gets very low, the patient will start showing signs of opportunistic infection
• As the CD4 count continues to go down, the viral load will go up
• If a patient has been diagnosed with HIV, you would monitor their CD4 count and measure their viral load
• Once their CD4 reaches a certain level you would start antiretroviral therapy

Question 38

What infections do you get when have extremely low CD4 count

Answer 38

Mycobacterium avium complex infections which are normal bacteria everywhere which normal people can deal with