pharm. biotech

1. HYBRIDOMA TECHNOLOGY
Unit- 3rd

2. CONTENTS:
HISTORY.
INTRODUCTION.
METHODOLOGY :
 CELL FUSION
 SELECTION
 SCREENING
 CULTURING
APPLICATIONS

3. HISTORY:
The production of monoclonal antibodies was invented by César
Milstein and Georges J. F. Köhler in 1975.
They were awarded noble prize for their work on monoclonal antibodies in
1984.
 The term hybridoma was coined by Leonard Herzenberg.
Leonard Herzenberg.

4. WHAT IS HYBRIDOMA TECHNOLOGY???
Hybridoma technology is a method for producing large numbers of
identical antibodies also called as monoclonal antibodies.
In this technique monoclonal antibodies are generated by fusing B-cells with
myeloma tumor cells which grow indefinitely in culture.
Such hybrid cell obtained by fusion of B-lymphocyte and myeloma cell is
called a Hybridoma.
HYBRIDOMA

5. The hybrid cell has the capacity of antibody production derived
from B cells.
It can divide continuously by the quality derived from Myeloma
cells.
By combining the desired qualities of both the cells, the
technology ensures large scale antibody production of single
specificity.
Monoclonal antibodies

6. METHODOLOGY:
 Laboratory animals (mammals, e.g. mice) are first exposed to the
antigen that an antibody is to be generated against.
 Usually this is done by a series of injections of the antigen, over
the course of several weeks.
 These injections are typically followed by the use of in
vivo electroporation, which significantly enhances the immune
response.
 The spleenocytes from spleen and myeloma cells from bone
marrow of the immunized mouse are isolated.

8. The fusion of the B cells with myeloma cells can be done using:
Physical method: Electrofusion.
Chemical method : Polyethylene glycol.
PEG mediated Cell fusion Electrofusion

9. Cell fusion leading to formation of Hybridoma cell.

10. Nucleotide synthesis:
Nucleotide synthesis is essential for cell survival.
The two pathways for nucleotide synthesis are :
Denovo pathway. (synthesis of nucleotides from simple sugars, amino acids etc.)
Salvage pathway. (synthesis of nucleotides from intermediate of nucleotide
degradation pathways)
An important enzyme of salvage pathway is HGPRT.

11. SELECTION:
Process through which only hybridoma cells are selected by eliminating
unfused myeloma cells and unfused B cells
HAT medium is used for the selection of hybrid cells.
Fused cells are incubated in HAT medium (hypoxanthine- aminopterin -
thymidine medium) for roughly 10 to 14 days.
Elimination of unfused myeloma cells:
Removal of the unfused myeloma cells is necessary because they have the
potential to outgrow other cells, especially weakly established hybridomas
The myeloma cells first selected for fusion are hypoxanthine-guanine
phosphoribosyl transferase (HGPRT) mutant cells(raised by using 8-azaguanine
which causes mutations).
Thus the unfused myeloma cells in the medium cannot carryout nucleotide
synthesis through salvage pathway due to the deficiency of HGPRT.

12. Where as, Aminopterin blocks the denovo pathway.
Hence, unfused myeloma cells die, as they cannot synthesize
nucleotides.
Elimination of unfused B cells:
Unlike the unfused myeloma cells, the B cells can carryout nucleotide
synthesis through Denovo pathway as they are not HGPRT mutants.
But due to the lack of infinite cell division capability the B cells which
survive in the HAT medium die within 7-10 days.
Thus, only the Hybrid cells survive on HAT as they have HGPRT enzyme
from B cells and the repeated cell division property of myeloma cells.

13. SELECTION OF HYBRIDOMA

14. SCREENING PROCESS:
The next stage is a rapid screening process, which identifies and selects only those
hybridomas that produce antibodies of appropriate specificity.
The screening technique used is called ELISA. The hybridoma culture supernatant,
secondary enzyme labeled antibodies, are then incubated, and the formation of a
colored product indicates a positive hybridoma.
ELISA SCREENING

15. CULTURING :
Culturing of hybridomas:
In vitro
In vivo
IN VITRO CULTURING:
The hybridoma cell that produces the desired antibodies can be
cloned to produce many identical daughter clones.
Once a hybridoma colony is established, it will continually grow in
culture medium produce antibodies.
Multiwell plates are used initially to grow the hybridomas, and after
selection, are changed to larger tissue culture flasks. This maintains
the well-being of the hybridomas and provides enough cells for
cryopreservation and supernatant for subsequent investigations.
The culture supernatant can yield 1 to 60 µg/ml of monoclonal
antibody, which is maintained at -20 °C or lower until required.

16. IN VIVO CULTURING:
This procedure involves introduction of hybridoma cells into the peritoneal cavity
if the animal.
The ascetic fluid is isolated from the animal which is used for the isolation and
purification of the antibodies.
IN-VITRO AND IN-VIVO CULTURING

19. APPLICATIONS:
BIOCHEMICALANALYSIS:
Monoclonal antibodies are used in immunoassays like:
RIA( radioimmuno assay )
ELISA (Enzyme linked immuno sorbent assay)
These assay measure the concentrations of hormones like
Insulin
Thyroxine
TSH etc.
Blood grouping test
Pregnancy test ( Human chorionic gonadotropin)
CANCER:
Estimation of plasma carcinoembryonic antigen in colorectal cancer,
Prostate specific antigen for prostate cancer.

20. DIAGNOSIS OF INFECTIOUS DISEASES:
These antibodies could be used for detection of infections such as
typhoid , syphilis etc.
DIAGNOSTIC IMAGING:
Radiolabelled monoclonal antibodies are used in the diagnostic
imaging of diseases, this technique is called immunoscintigraphy.
 Applications in detection of Myocardial infraction, Deep vein
thrombosis etc.
Detection of Tumor markers for various cancers
ex: carcinoembryonic antigen (CEA) - cancer of stomach, colon,
pancreas.
Alpha fetoprotein – cancer of Liver .
CANCER TREATMENT:
Monoclonal antibodies against the surface antigens of cancer cells
mediate cancer cell death through ADCC( antibody mediated cell
dependent cytotoxicity )
Phagocytosis etc.

21. IMMUNOSUPRESSION:
The monoclonal antibodies could be used as
immunosupressive agent after organ transplantation.
Ex: OKT3 against CD3 of T cells has been successfully used
in renal and bone marrow transplantation.

22. Home – work
&
Thank you….