(i)
mammalian
cells
and
(ii)
bacterial
cells,
particularly
E.
coli.
Initially,
antibody
genes
were
taken
from
hybridomas,
cloned
into
plasmid
vectors
and
expressed
as
complete
antibodies
in
mammalian
cells.
However,
later
genes
for
different
small
fragments
of
antibodies
(e.g.
Fv,
FAb,
Fc
or
even
single
chain
Fv
=scFv)
could
be
cloned
and
expressed
in
bacteria.
(Fig.
12.
2).
Expression
in
mammalian
cells
becomes
important,
when
glycosylation
of
antibodies
is
desired.
However,
lack
of
glycosylation
does
not
influence
antigen
binding
capacity
of
Fv
or
Fab
fragments
or
of
complete
antibody,
although
it
does
affect
some
of
the
effector
functions
attributed
to
Fc
fragment.
Therefore,
for
industrial
production
of
antibodies,
glycosylation
is
immaterial
and
E.
coli
can
be
used
as
a
useful
expression
system.
|
