Dec 5, 2012 (5 years and 7 months ago)




S. Adebayo, PhD

"The World is a book and those who do no travel read
only a page"

Saint Augustine


Biotechnology encompasses any technique that
uses living organisms in the production or
modification of products.

Thus, biotechnology products broadly refer to
biopharmaceutical drugs generated through
researches in cell biology, genetics and
recombinant DNA technology.

Recombinant DNA (rDNA) and monoclonal
antibody (MAb) are providing exciting
opportunities for new pharmaceuticals
development as well as new approaches to drug


During the last decade, over 359 biotechnology products
were developed by more than 40 pharmaceutical
companies for indications ranging from hemophilia, sepsis,
skin ulcers, and rheumatoid arthritis to cancer.

More than one
third of all biotechnology products are
geared toward cancer therapy

More than 29 were under development for HIV, AIDS and
related diseases.

About 19 other products were being developed for
autoimmune diseases.

Research and development network


Biotechnology derived drugs are being applied in
cancer therapy, HIV, AIDS and AIDS
related and
autoimmune diseases

In diagnostic investigations

As blood substitutes, clotting factors, etc.

**Human insulin (approved in 1982) and human
growth factor were the first set of biotechnology
products to be applied for human therapy.

Biotechnology techniques and processes
(Evans, P. R.
Biotechnology and Biological Preparations in Encyclopaedia of PT vol. 1, 3


Recombinant DNA (rDNA)

DNA constitutes the genes through which
cells reproduce and are able to maintain

DNA consists of two strands connected by
bases adenine (A), guanine (G), cytosine
(C) and thymine (T).

The order of base arrangement (in pairs)
along the two strands of DNA constitutes a
specific gene for a specific trait.

Recombinant DNA (rDNA)

A typical gene consists of 100’s of bases arranged
in pairs according to the A
T and C
G rule.

The pattern constitutes the DNA message for
maintaining cells and organisms and for building
next generation.

Creation of new cell or organism involves
unwinding and separation of the DNA strands and
subsequent attachment to new bases within the
cell according to the A
G rule.

Recombinant DNA (rDNA)

DNA also codes for information required
for the production of the 23 amino acids.

The arrangement of these a.a. in a vast
array of ways give rise to thousands of
different proteins

When DNA molecules are selectively hydrolyzed
, molecules of two
different DNA’s can be joined (recombinant DNA).

Recombinant DNA (rDNA)

Other techniques involved are
replication, separation, identification
which permit the production of large
quantities of purified DNA fragments.

Recombinant DNA technology allows
the removal of a specific piece of
DNA out of a large complex

Recombinant DNA (rDNA)

The ability to join two different pieces of
DNA together at specific sites within the
molecule is achieved with two enzymes

a restriction endonuclease


DNA ligase

This technology permits utilization of non
human cells (e.g. special strain of
E. coli
to manufacture proteins identical to those
produced in human cells.

Recombinant DNA (rDNA)

DNA technology is been utilized to
diagnose diseases.

This method utilizes small pieces of DNA
to search a cell for viral infection or
genetic defect.

DNA probe has been applied in
testing for infectious diseases,
cancer, genetic defects and disease

Quality control tests in r

Evans, P. R. Biotechnology and Biological Preparations
in Encyclopaedia of PT vol. 1 3


Approved rDNA biologicals (hormones)

Approved rDNA biologicals (growth factors)

Approved biologicals (blood factors and
interleukins) (rDNA products)

Monoclonal Antibodies

When an antigen molecule enters the body, an
immune response is initiated.

An antigenic molecule may contain several
different antigenic determinants to which each
line of

will proliferate,

secreting an immunoglobulin molecule that fits a
single antigenic determinant or part of it.

Monoclonal antibodies are produced by
perpetuating the expression of a single

Monoclonal Antibodies (Cont.)


technology permits
large quantity production of identical,
monospecific antibodies

Monospecific antibodies are produced
by the fusion of
stimulated with a specific antigen,
immortal myeloma


Monoclonal Antibodies (Cont.)

The resultant hybridomas are then
maintained in cultures and are
capable of producing large amounts
of antibodies.

From hybrid cells, a specific line or
clone producing monospecific
immunoglobulins can be selected.

Immunoglobulin F

Large proportions of the currently
used antibodies belong to the
immunoglobulin F (i.e. IgG) subclass.

The IgG molecule has a MW 150
180 kD and consists of two
polypeptide chains connected by di
sulphide bonds.

Immunoglobulin F…

The heavy and light chains consist of two zones:
the constant and variable domains.

The constant domain amino acids are relatively
conserved among Ig’s of specific class (e.g. IgGi,

The variable domains of antibodies are highly
heterogeneous and it is this domain that gives
antibodies its binding specificity and affinity (Fig.

Monoclonal antibodies

PSWC 2007 Post
Satellite EAPB and EUFEPS

Workshop on Monoclonal AntiBodies

A schematic representation of the structural
and functional domains of IgG.

Human anti
mouse antibodies

Most of the monoclonal antibodies in clinical trials
have been derived from mice

A patient exposed to the antibodies typically
develops detectable levels of antibody responses
to the foreign monoclonal antibody within two to
four weeks.

On giving additional doses, a typical allergic
reaction is elicited

i.e. chills, urticaria, wheezing

and the antibody is rapidly cleared from the

made antibodies

made antibodies overcome the lack
of intrinsic antitumour activity and
immunogenicity of many murine
monoclonal antibodies.

They retain the binding specificity of the
original rodent antibody determined by
the variable regions but can potentially
activate human immune system through
their human constant regions.

made antibodies…

Smaller fragments that contain
immunoglobulin binding sites e.g. F(ab)2
and Fab′ do not contain the lower binding
domain of the molecule.

A smaller sized molecule tends to be less
immunogenic but may have greater
tumour penetration ability than the larger
structure (Fig 2).

Approved biologicals (Mabs)

A historical timeline of therapeutic monoclonal
antibody approvals in the United States relative to the
development of antibody generation technologies.

Polymerase Chain Reaction

Biotechnology process involving substantial amplification (>
100,000 fold) of a target nucleic acid sequence (a gene). It
is an enzymatic reaction which occurs in 3 steps:

DNA is denatured to separate the 2 strands

A nucleic acid primer is hybridized to each DNA strand at
a specific location within the nucleic acid sequence

DNA polymerase enzyme is added for extension of the
primer along the DNA strand to copy the target nucleic
acid sequence.

Gene Therapy

Exogenous genetic material is transferred
into somatic cells to correct an inherited
or acquired defect.

It may also be used to introduce a new
function or property into cells.

Gene therapy has been applied to diseases
such as cystic fibrosis, hemophilia, sickle
cell anemia and diabetes.

Gene Therapy…

Ethical consideration does not permit intervention
with germ cells.

Self renewing stem cells are used for therapeutic
transfer of genetic materials into end
differentiated somatic cells

Since stem cells can renew themselves, the
inserted gene will remain in place throughout
subsequent generation of differentiated cells or
tissue population.

Gene Therapy

For example, a patient’s cells (T
are harvested and grown in the laboratory.

A gene from a viral carrier (e.g. moloney murine
leukemia virus) is supplied which starts to
produce the missing protein necessary to correct
the deficiency.

The genes with extra functional cells are then
returned to the patient and the normal protein is
produced and released thereby alleviating the

Gene Therapy…

Gene therapy has been used to treat
adenosine deaminase deficiency (ADA).
The gene coding for ADA is found on
chromosome 20.

Gene deletion and point mutation lead to loss of
or severe reduction in ADA enzymatic activity
resulting in clinical presentation of severe
combined immunodeficiency syndrome
(SCID) causing death in childhood or

Nucleotide Blockade/Antisense

This technology focuses on the study of
function of specific proteins and intra
cellular expression.

The sequence of a nucleotide chain that
contains information for protein synthesis
is called the sense sequence;

nucleotide chain complementary to the
sense sequence is called the antisense

Nucleotide Blockade/Antisense

Antisense drugs recognize and bind to the
nucleotide sense sequence of specific
messenger RNA (mRNA) molecule and
prevent the synthesis of unwanted proteins
and actually destroying the sense molecules
in the process.

When antisense RNA is introduced into a cell
by cloning technique, the specific gene of
interest is cloned in an expression vector in
the wrong orientation.

Nucleotide Blockade/Antisense

A complementary mRNA is thus
created to match an abnormal

When the 2 mRNA strands
complex together, translation to
form the disease
protein is prevented.

Products of Biotechnology

Anticoagulant drug


Antisense drugs

Fomivirsen sodium
injection is approved
for local treatment of
cytomegalovirus (CVM) retinitis in patients
with AIDS

Efavirenz (Sustiva

A non
nucleoside reverse transcriptase inhibitor
the first anti
HIV drug to be approved by FDA
for once daily dosing in combination with other
HIV drugs.

Products of Biotechnology (Cont.)

Clotting factors



Recombinant anti
hemophiliac factor
indicated for the treatment
of classical hemophilia A in which there is a
demonstrated deficiency of clotting factor (Factor

Growth factor

Becaplemin (regranex

Systemic growth hormone

recombinant (Humatrope®)

Products of Biotechnology (Cont.)…

Colony stimulating factors





Genetically engineered vaccines
use a synthetic copy of the protein coat of a
virus to “fool” the body immune system into
mounting a protective response.

Approved biologicals (interferons)

Approved biologicals (enzymes)

Approved biologicals (vaccines and

Approved biologicals (tissue and cell

Approved biologicals (blood derivatives
and natural extracts)

Exercise (5 % of CW)

products on T&T Drug market, Hospital or

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