Antibodies as a Diagnostic Tool

Question 1

How can manufactured antibodies be used as a therapeutic method?

Answer 1

They can be used for

1. Prophylaxis againstmicrobial infections
2. Anti-cancer therapy
3. Removal of T-cells from bone marrow grafts (to prevent autoimmunity)
4. To Block cytokine activity
5. Anti-calcitonin gene-related peptide (CGRP)for migraine

Question 2

How may antibodies be produced?

Answer 2

Produced by the patient

1. in autoimmune disease
2. for defence against infection and in Billy’s case, used to diagnose his infection

Manufactured antibodies

1. antisera from immunised animals (polyclonal)
2. monoclonal antibodies
3. “genetically engineered” antibodies

Question 3

How can you use Antibodies in diagnosis of diseae?

Answer 3

• Blood group serology
• Quantitative immunoassays
  
  • hormones
  • antibodies
  • antigens
• Immunodiagnosis
  
  • Infectious diseases
  • Autoimmunity
  • Allergy (IgE)
  • Malignancy (myeloma)

Question 4

How can antibodies be modified to serve diagnoistc or therapeutic effects?

Answer 4

They can be added a

• flourescent dye
• enzymes
• drugs
• Magnetic beads (purification of cell types)

–> used for targeted treatment at site/ diagnosis

–> added to site of antibodies not needed in binding

Question 5

What is a anti-anitbody?

Answer 5

It is an antibody binding to a different antibody

–> antibody can be labelled indirectly by attachments to 2nd antibody

Question 6

Explain the process of manufacturing monochlonal antibodies

Answer 6

1. Animal challanged with antigen and prodcued splenic b cells
2. Myeloma cells (disprogrammed myeloma)

1+2 Fused–> give rise to hybridomas

Hybridomas are grown in medium (immortal) and produce antibodies that are regularly harvested and purified –> very very expensive and complicated

Question 7

Explain the process of producing antibodies via recombinant DNA technology

Answer 7

Via the use of phages

• Isulate genes that codoe for variable region of antibodies (region for binding to antigen)
• construct a region that encoorperates all variable genes into a bacteriophage coat
• gives rise to polychlonal bacteriophage populations
• selct for disired v region bacteriophage

Question 8

What is ELISA?

When is it used?

Answer 8

Ein antikörperbasiertes Nachweisverfahren zum Nachweis von Antikörpern

–> Enzyme Linked Immunosorbent Assay

• There is an antibody on a surface
• Probe (whihc might contains antigen) is suspended on surfact
• If anitigen in probe–> it binds to antibodies
• 2nd. flush of antibodies (labelled) distributed among surfact
• If antigen bound to antibody–> 2nd antibodies bind again and show the antigen

Question 9

Explain the method of rapid testing using antibodies

Answer 9

1. Test has a conjugate plate which containes antibodies conjugated to gold nanopartilcles
2. When probe (with antigen) is suspended on sample pad, it moves towards other sidw via capillary forces
3. Antigen binds to antibodies
4. Antigen-antibody complex binds to test line which also has antibodies on it
5. Some of the labelled antibodies also bind to the controll line to make it a valid test

Question 10

What is flow cytometry?

When is it used

Answer 10

Used to detect the presence of specific cells–>

• Every cell type has different CD markers
• Labelled antibodies designed to bind to CD marker surface proteins
• Flourescent colour detected by laser –> detects number of cells in a particular probe

–> very complex and expensive