Biomedical Engineering Reference
In-Depth Information
(1946-1995) and César Milstein (1927-2002) published their landmark
paper in Nature describing monoclonal antibody technology (29).
B.
Monoclonal antibodies
Introduction
Monoclonal antibodies are antibodies derived from a clone of antibody
producing cells that grow continuously in tissue culture and secrete anti-
bodies of an identical and single specificity. The discovery of monoclonal
antibody technology by Köhler and Milstein revolutionized biomedicine
and has become a billion dollar industry. Remarkably, the inventors did
not patent the technology, but their ingenious invention earned them the
Nobel Prize in Medicine in 1984. Today, monoclonal antibodies are not
only used as experimental tools by biomedical scientists, but as diag-
nostic tools in infectious disease, in screening for certain cancers, and
as treatments for various diseases. Monoclonal antibody technology will
continue to evolve for use in identifying disease markers and for use in
fighting human diseases.
Production of monoclonal antibodies
The production of monoclonal antibodies relies on somatic cell ge-
netic techniques. Somatic cell genetics involves the fusion of two dif-
ferent types of cells to produce a hybrid cell with one nucleus but with
chromosomes contributed from both parental cells. In the case of an-
tibody producing cells, Köhler and Milstein demonstrated that it was
possible to immortalize cells producing antibodies of a desired speci-
ficity using somatic cell genetics by taking advantage of the indefinite
growth characteristics of a particular type of tumor cell, a myeloma, and
the antibody specificity of a B cell from an immunized animal.
The basic procedure for producing monoclonal antibodies is as fol-
lows. Spleen cells from immunized mice are isolated as a single cell
suspension and fused to a myeloma cell line that grows in tissue cul-
ture. The fusion is now carried out using polyethylene glycol (PEG),
although originally the Sendai virus, which fuses membranes, was used
to facilitate fusion. The spleen cells (including the B cells) will die within
a day or two in culture unless “rescued” by fusion with the myeloma.
In turn, the myeloma cells that are used have been rendered defec-
tive in the enzyme h ypoxanthine g uanine p hospho r ibosyl t ransferase, or
HGPRT, an enzyme involved in nucleic acid biosynthesis. These cells
will die in tissue culture medium that is supplemented with h ypoxanthine,
a minopterin and t hymidine (referred to as HAT medium) unless rescued
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