Engineering Antibodies 2 Immunotherapeutic Examples MSc Programme University of Nottingham 14th Febr

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Engineering Antibodies (2)Immunotherapeutic
ExamplesMSc Programme University of
Nottingham14th February 2005

• by
• Mike Clark, PhD
• Department of Pathology
• Division of Immunology
• Cambridge University
• UK
• www.path.cam.ac.uk/mrc7/

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University Research Programmes

• Immunosuppression
• CD4, CD3, monovalent CD3, CD52 (Campath)
• Tumour Therapy
• CD52 (Campath), bispecific CD3
• Organ Transplantation
• CD52, CD3, CD4, synergistic CD45 pair
• Allo and auto-immunity
• RhD, HPA-1a
• Chronic Inflammation
• CD18, VAP-1

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Declaration of interests (rights as an inventor)

• CD52 IlexOncology/Genzyme (Campath
  humanisation)
• CD4 TolerRx/Genentech (for induction of
  tolerance)
• CD4 BTG (improved method of humanisation)
• CD3 BTG /TolerRx (immunosuppression and
  tolerance)
• CD18 Millennium Pharmaceuticals
• VAP-1 BioTie / University collaboration
• RhD NBS / University collaboration
• HPA-1a NBS / University collaboration

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The antibody isotype is important
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Chimeric and humanised
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Rat IgG2b is effective in therapy
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Human IgG1 also effective in therapy
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Antibodies (eg CD52 Campath) can be effective in
killing cancer cells (BCLL)
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Fetomaternal alloimmune thrombocytopenia

• Maternal IgG raised against fetal platelet
  alloantigens can cross the placenta and cause
  fetal platelet destruction
• If the fetal platelet count falls dangerously
  low, cerebral hemorrage or death may result
• Current therapies are intrauterine platelet
  transfusion and maternal therapy with high dose
  IVIG

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Can a protective antibody be developed?

• 90 severe cases FMAIT are due to antibodies
  against the alloantigen HPA-1a on GPIIIa
• Single B cell epitope (Leu-33) could be blocked
  to prevent the binding of harmful antibodies
• Outcome depends on antibody titre
• Williamson et al. Blood 1998 92 2280
• Jaegtvik et al. Br J Obs Gynae 2000 107 691

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Ideal properties of an antibody for FMAIT therapy

• HPA-1a specificity (B2 variable regions)
• able to cross the placenta
• inactive in FcgR-mediated cell destruction
• unable to activate complement

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RhD HPA-1a
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Chemiluminescent response of human monocytes to
sensitised RBC
Fog-1
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antibodies
120
G1
G1D a
100
G1D b
80
G1D c
chemiluminescence
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G1D ab
40
G1D ac
G2
20
G2D a
0
G4
-20
G4D b
0
5000
10000
15000
20000
25000
30000
G4D c
antibody molecules/cell
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Inhibition of chemiluminescent response due to 2
mg/ml Fog-1 G1 by other Fog-1 antibodies
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Inhibition by Fog-1 antibodies of ADCC due to
clinically relevant polyclonal anti-RhD (at
3ng/ml)
120
100
80
G1D ab
G2
G2D a
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RBC lysis
G4
G4D b
40
20
0
0.1
1
10
100
1000
10000
inhibitor antibody concentration, ng/ml
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HuVAP antibody
VAP-1
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Multistep paradigm of neutrophil adhesion
Endothelium
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Role of VAP-1
sVAP-1
Modified Fc region
Anti VAP-1
Selectin
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Capillary flow system
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Neutrophil adhesion assay
VAP-1
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Human IgG1 wildtype anti-VAP-1 antibody
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HuVAP mutated anti-VAP-1 antibody
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Brief Acknowledgements
Mike Clark Dept of Pathology Kathryn Armour
Chris Kirton Cheryl Smith Lorna
Williamson National Blood Service
Transfusion Medicine