Antibody therapeutics & diagnostics
Introduction
1. Market overview
Therapeutic antibodies
First antibody in clinic: 1986
Gaining importance
o Canonical antibodies = most popular
o Other formats: coupled to other drugs, multiple targets,
antibody fragments
Indications
o Main indication = cancer
o Infectious diseases
o Neurology (difficult to reach the brain over the BBB ->
less approved antibodies but population of patients is
the same as the cancer patients’ population)
>100 antibodies approved: many hit the same target
o Improvement of earlier versions
Different administration route
Lower immunogenicity
Example: adalimumab vs infliximab
Infliximab: approved before adalimumab IV
Adalimumab: SC = more successful
o Combination therapies with antibodies: better to own
each component
o Lucrative market: “share a piece of the pie”
2. Brief history
Immunity
= state/ quality of being resistant to a particular infectious disease
or pathogen
1) General concept: 18th century
Smallpox – lady Mary Wortley Montagu
Turkey: pus collected from mild cases inoculating children
protected
Cow pox – Edward Jenner
Diary girls in contact with cow pox protected
Tetanus & diphtheria – Emil von Behring
Serum transfer protected
Hypothesis: receptors that bind antigens + could activate the
complement pathway
, 2) Plasma B-cells involved in antibody generation
3) Clonal selection theory: a B-cell makes a single specific antibody
4) Molecular structure of antibodies
5) Köhler & Milstein (1975)
Method to generate monoclonal antibodies
Antibodies – name
Serum electrophoresis
- Albumin
- ⍺-, β, γ-globulins
Plasma from rabbits
immunized with
ovalbumin
γ-globulins peak decreases after incubation with ovalbumin:
disappearing proteins = immunoglobulins
3. Immune system
Adaptive/ specific immune system:
Body challenged by foreign pathogen
Macrophages engulf pathogens non-selectively & break them
down internally
Proportion of macrophages (dendritic cells) present antigenic
fragments of pathogen to specific lymphocytes: helper T
lymphocytes (TH cells)
o Release cytokines
o Cytokines stimulate B-cells that produce antibodies
specific to antigen to divide and form clones (clonal
selection)
Most of B-cell clones: short-lived plasma cells that produce
large quantities of specific antibody (2000/second (!))
Small proportion of clones: differentiate into long-lived
memory B-cells
,Innate/ non-specific immune system:
First line of defense against infection
All components are present before the infection
o Function and efficiency does not change with repeated
exposure
o Not specific
Components
o Physical barriers: e.g.;
- Skin: prevents pathogen penetration
- Bodily fluids (e.g., mucus, tears, saliva, …): collect and
clear pathogens
- Low pH in stomach
o Complement system (collaborates antibodies)
o White blood cells (macrophages, neutrophils, natural killer
cells, dendritic cells, …)
- Dendritic cells: antigen presenting cells: bridge between
innate and adaptive immune system ‘eats’ pathogen +
presents it to T-helper cell
, 1) Dendritic cell ‘eats’ pathogen -> presents it to T-helper cell
2) T-helper cell releases cytokines
3) Cytokines affect the other immune cells
4) B-cells displays antigen+antibody complex
5) The complex is internalized
6) Displayed
7) Recognized by TH cells
Slide 22-23; zie infectieziekten !!!!
Memory cells: long living + produce low levels of circulating antibodies
Second infection: production of antibodies = faster + higher levels
Pathogen cannot reproduce sufficient to cause disease
Individual is said to be immune
Antibodies = most divers class of proteins
Antigen: antibody generators
4. Antibody structure
Y-shaped proteins (but flexible needed to adapt to pathogen)
Dimers: left and right are identical
Fab domains
Antigen binding
S-S linked
Hinge region
Flexible region that
links CH1 and CH2
Fc domain
Effector function
S-S linked
Sandwich of 2 β-sheets each sheet antiparallel
Loops between β-strands
o Folds = stable; rigid
o Loops = flexible
Following N- to C-terminus: you jump from
one sheet to another through the loops
between them
Introduction
1. Market overview
Therapeutic antibodies
First antibody in clinic: 1986
Gaining importance
o Canonical antibodies = most popular
o Other formats: coupled to other drugs, multiple targets,
antibody fragments
Indications
o Main indication = cancer
o Infectious diseases
o Neurology (difficult to reach the brain over the BBB ->
less approved antibodies but population of patients is
the same as the cancer patients’ population)
>100 antibodies approved: many hit the same target
o Improvement of earlier versions
Different administration route
Lower immunogenicity
Example: adalimumab vs infliximab
Infliximab: approved before adalimumab IV
Adalimumab: SC = more successful
o Combination therapies with antibodies: better to own
each component
o Lucrative market: “share a piece of the pie”
2. Brief history
Immunity
= state/ quality of being resistant to a particular infectious disease
or pathogen
1) General concept: 18th century
Smallpox – lady Mary Wortley Montagu
Turkey: pus collected from mild cases inoculating children
protected
Cow pox – Edward Jenner
Diary girls in contact with cow pox protected
Tetanus & diphtheria – Emil von Behring
Serum transfer protected
Hypothesis: receptors that bind antigens + could activate the
complement pathway
, 2) Plasma B-cells involved in antibody generation
3) Clonal selection theory: a B-cell makes a single specific antibody
4) Molecular structure of antibodies
5) Köhler & Milstein (1975)
Method to generate monoclonal antibodies
Antibodies – name
Serum electrophoresis
- Albumin
- ⍺-, β, γ-globulins
Plasma from rabbits
immunized with
ovalbumin
γ-globulins peak decreases after incubation with ovalbumin:
disappearing proteins = immunoglobulins
3. Immune system
Adaptive/ specific immune system:
Body challenged by foreign pathogen
Macrophages engulf pathogens non-selectively & break them
down internally
Proportion of macrophages (dendritic cells) present antigenic
fragments of pathogen to specific lymphocytes: helper T
lymphocytes (TH cells)
o Release cytokines
o Cytokines stimulate B-cells that produce antibodies
specific to antigen to divide and form clones (clonal
selection)
Most of B-cell clones: short-lived plasma cells that produce
large quantities of specific antibody (2000/second (!))
Small proportion of clones: differentiate into long-lived
memory B-cells
,Innate/ non-specific immune system:
First line of defense against infection
All components are present before the infection
o Function and efficiency does not change with repeated
exposure
o Not specific
Components
o Physical barriers: e.g.;
- Skin: prevents pathogen penetration
- Bodily fluids (e.g., mucus, tears, saliva, …): collect and
clear pathogens
- Low pH in stomach
o Complement system (collaborates antibodies)
o White blood cells (macrophages, neutrophils, natural killer
cells, dendritic cells, …)
- Dendritic cells: antigen presenting cells: bridge between
innate and adaptive immune system ‘eats’ pathogen +
presents it to T-helper cell
, 1) Dendritic cell ‘eats’ pathogen -> presents it to T-helper cell
2) T-helper cell releases cytokines
3) Cytokines affect the other immune cells
4) B-cells displays antigen+antibody complex
5) The complex is internalized
6) Displayed
7) Recognized by TH cells
Slide 22-23; zie infectieziekten !!!!
Memory cells: long living + produce low levels of circulating antibodies
Second infection: production of antibodies = faster + higher levels
Pathogen cannot reproduce sufficient to cause disease
Individual is said to be immune
Antibodies = most divers class of proteins
Antigen: antibody generators
4. Antibody structure
Y-shaped proteins (but flexible needed to adapt to pathogen)
Dimers: left and right are identical
Fab domains
Antigen binding
S-S linked
Hinge region
Flexible region that
links CH1 and CH2
Fc domain
Effector function
S-S linked
Sandwich of 2 β-sheets each sheet antiparallel
Loops between β-strands
o Folds = stable; rigid
o Loops = flexible
Following N- to C-terminus: you jump from
one sheet to another through the loops
between them
