Download Recombinant Vaccine

Recombinant Vaccines
A recombinant vaccine is a vaccine produced
through recombinant DNA technology. This
involves inserting the DNA encoding an
antigen (such as a bacterial surface protein)
that stimulates an immune response into
bacterial or mammalian cells.
Types of Recombinant Vaccine
• 1) Subunit recombinant vaccines: These are
components of the pathogenic organisms. Subunit
vaccines include proteins, peptides and DNA.
• 2) Attenuated recombinant vaccines: These are
genetically modified pathogenic organisms
(bacteria, viruses) that are made non-pathogenic
and used as vaccines.
• 3) Vector recombinant vaccines: These are the
genetically modified viral vectors that can be used
as vaccines against pathogens.
Recombinant Vaccines
Few diseases against which recombinant
vaccines have been produced are:
Viral diseases: Chicken pox, Genital ulcers,
hemorrhagic
fever,
acute
infantile
gastroenteritis etc.,
Bacterial diseases: Cholera, pneumonia,
tetanus, tuberculosis, typhoid, meningitis etc.,
Parasitic diseases: Malaria, Filariasis, sleeping
sickness etc.,
Monoclonal Antibodies
• Monoclonal antibodies (MAb) is a single type of
antibody that are made by identical immune cells
which are directed against a specific epitope (the
part of the antigen that is recognized by the
antibody)
• Hybridoma Technology: The production of
monoclonal antibodies by the hybrid cells
(antibody-producing B-lymphocytes and myeloma
cells in vitro) is referred to as Hydridoma
Technology.
Hybridoma Technology
• The establishment of hybridoma and production
of monoclonal antibodies involves the following
steps:
Immunization
Cell fusion
Selection of hybridomas
Screening the products
Cloning and propagation
Characterization and storage
Hybridoma Technology
• It is technique of producing hybrid cell lines
called “hybridomas” by the fusion of a specific
antibody-producing lymphocyte B cell with a
myeloma cell that has an ability to grow in
tissue culture
• Hydridoma produce antibodies that have single
specificity and are called monoclonal
antibodies.
• This technique was discovered Georges Kohler
of West Germany, Cesal Milstein of Argentina
and Niels Jerne of Denmark in 1975.
• They were awarded Nobel Prize for Physiology
Georges Kohler
Cesal Milstein
Niels Jerne
Antibody producing lymphocyte B cell are isolated
from the spleen cell of mouse immunized with red
blood cells from sheep
Single myeloma cell is a bone marrow tumour cell
capable of multiplying indefinitely.
Fused hybrid cells or hybridoma have the antibody
producing capability inherited from lymphocytes
and have the ability to grow continuously or
immortal like malignant cancer cells.
Steps in monoclonal antibody production by hybridoma technology
1. Immunize a rabbit through repeated injection
of a specific antigen for the production of
specific antibody, facilitated due to
proliferation of the desired B cells.
2. Produce tumors in a mouse or a rabbit.
3. Culture separately the spleen cells that
produce specific antibodies and the
myeloma cells that produce tumors
4. Myeloma cells cannot synthesize antibodies
as they lack HGPRT gene required for the
synthesize the enzyme, hypoxanthine
guanine phosphoribosyl transferase
Fusion
• Fusion of spleen cells to myeloma cells is
induced using polyethylene glycol (PEG), to
produce hybridoma
• Hybridomas are grown in selective
hypoxanthine aminopterin thymidine (HAT)
medium.
• HAT medium contains a drug, aminopterin
that blocks one pathway for nucleotide
synthesis, making the cells dependent on
another pathway that needs HGPRT enzyme,
which is absent in myeloma cells.
• Myeloma cells that do not fuse with B cells
will die.
• B cells that do not fuse will also die because
they lack tumorigenic property of immortal
growth.
Selection and Storage
• Select desired hybridoma for cloning and
antibody production
• Prepare single cell colonies that can grow
and use them to screen of antibody
producing hybridomas
• Only one in several hundred cell hybrids
will produce antibodies of the desired
specificity
• Culture selected hybridoma cells for the
production of monoclonal antibodies in
large quantities
• Hybridoma cells can be frozen for future
use or can be injected in the body of an
animal, so that antibodies will be
produced in the body and recovered later
Applications
Serological:
• Identification of ABO blood groups.
Diagnosis:
• Detection of pregnancy
• Detection of pathogens
• Diagnosis of Cancers, hormonal disorders, infectious
diseases.
Therapeutic Applications:
To destroy pathogens
In the treatment of Cancer
In the treatment of AIDS
In the treatment of Autoimmune diseases