Immunotherapy

Question 1

What is Polyclonal antiserum?

Answer 1

Mix of A that target several epitopes on a specific antigen

Question 2

What is monoclonal antibody?

Answer 2

Monoclonal Ab target single type of epitope on a specific antigen

Question 3

What is 1 key use of polyclonal antiserum

Answer 3

1.To treat Hepatitis B virus newborn with Hepatitis B Immunoglobulins (HBIG).

infection stays with child for life, cause chronic liver failure.

Derived from healthy donated human blood, given to child for first 6 months, tgt with HBV vaccine.

2.To treat px post-liver transplan

Question 4

Limitation of polyclonal antiserum

Answer 4

-expensive
-low supply
-batch variations

Question 5

Use of Intravenous Immunoglobulin (IVIG)?

Answer 5

IVIG is a mixture of antibodies purified from healthy human donors

for inflammatory disease e.g. auto-antibody mediated cytopenia

Question 6

What is the method used to produce monoclonal Ab?

Answer 6

hybridoma method:

primary mouse B lymphocytes fused with immortal myeloma –> form hybridomas –> isolated and expanded indefinitely in vitro –> large quantities of mAb

Question 7

What happened to CAMPATH

Answer 7

CAMPATH, a rodent antibody, showed great promise as cancer therapy at first due to large reduction of leukemia cancer cells –> but ultimately failed as after initial dose, the subsequent dose stopped working, all px succumbed to malignant disease.

Question 8

Why did CAMPATH fail?

Answer 8

Due to human anti-mouse antibody response (HAMA)

– human body saw mouse Ab as foreign protein antigen, px own Ab binds to CAMPATH and neutralise it, hence all subsequent doses after initial dose failed

Question 9

How was the HAMA challenge solved?

Answer 9

1. Chimerization of mouse antibodies into human‐mouse variants
2. Humanization of mouse antibodies
3. Making fully human antibodies, bypass the mouse completely

Question 10

Chimerisation principles?

Answer 10

Chimerisation describes engineering a recombinant protein with a mouse FAB region attached to a human Fc region, to make a mouse-human chimeric protein

Question 11

1 example of chimeric monoclonal Ab therapy to treat cancer?

Answer 11

Anti-CD20: Rituximab/Rituxan

Target CD20 B-cell marker, deplete B cells.

Treat px with non-Hodgkin B-cell lymphoma + chronic inflammatory diseases with B cell as underlying pathology

Question 12

1 example of chimeric monoclonal Ab therapy to treat rheumatoid arthritis?

Answer 12

Anti-TNF-α, Infliximab

Treat Rheumatoid arthritis (RA)

Targets cytokine TNF-α, the main driver associated with RA.

Question 13

Humanisation principles?

Answer 13

Humanisation describes cloning and pasting Complementarity Determining Regions (CDR) regions from a mouse antibody into a human antibody scaffold.

Since we are grafting a small part of the mouse variable region, this gives us a more humanised antibody (90-95%)

Question 14

Developing Full Human Therapeutic Ab process

Answer 14

1. identify px with interesting autoimmune antibody response
2. Blood sampling From patient
3. Isolation of human B‐cells (CD20 selection) From blood of patient
4. Automated Discovery,
   High throughput screening And cloning of antibody genes
5. Recombinant Expression and functional testing of human antibodies