Abstract
A
century
after
the
initial
proposition
that
the
immune
system
has
the
capacity
to
fight
against
tumors,
evading
destruction
by
immune
cells
is
now
well
recognized
as
a
hallmark
of
cancer.
Recent
decades
have
witnessed
extraordinary
improvements
in
the
use
of
immunotherapy
against
malignancies
and
adoptive
transfer
of
Natural
Killer
(NK)
cells
stands
among
promising
tools
in
the
fight
against
cancer.
Clinical
studies
have
demonstrated
the
anti‐tumor
responses
generated
by
NK
cells
both
in
the
autologous
and
allogeneic
settings
in
various
cancers.
Direct
adoptive
transfer,
ex
vivo
activation
and/o r
expansion,
as
well
as
genetic
modification
of
NK
cells
aspire
novel
improvements
to
current
immunotherapy
strategies.
As
such
interventions
develop,
the
quest
for
better
preparation
of
NK
cell
based
therapies
continues.
This
thesis,
primarily
investigates
the
feasibility
and
potential
of
ex
vivo
expanded
NK
cells
for
cancer
immunotherapy.
Our
results
p roduced
a
system
that
has
the
capacity
to
expand
polyclonal
and
highly
cytotoxic
NK
cells showing
selective
anti‐
tumor
activity.
Protocols
for
expansion
of
these
cells
from
healthy
donors
and
patients
with
Multiple
Myeloma
(MM)
using
current
Good
Manufacturing
Practice
(cGMP)‐compliant
methods
have
been
optimized
in
conventional
cell
culture
systems
as
well
as
automated
bioreactors.
The
elevated
cytotoxic
activity
of
expanded
NK
cells
against
autologous
tumor
cells,
along
with
detailed
analysis
of
phenotypic
changes
during
the
expansion
process
has
subsequently
shifted
attention
to
the
interaction
between
NK
and
tumor
cells.
Both
as
a
basic
method
to
identify
these
interactions,
and
as
part
of
further
plans
to
use
genetically
retargeted
NK
cells
in
cancer
immunotherapy,
we
have
investigated
methods
for
efficient
lentiviral
genetic
modification
of
NK
cells.
This
study
has
resulted
in
an
optimized
stimulation
and
genetic
modification
process
for
NK
cells
that
greatly
enhances
viral
gene
delivery.
Along
with
NK
cell
stimulating
cytokines,
an
inhibitor
of
innate
immune
receptor
signaling
that
blocks
the
intracellular
detection
of
viral
RNA
introduced
by
the
vector
was
successfully
utilized
to
enhance
gene
transfer
efficiency,
also
constituting
a
proof‐
of‐concept
for
various
other
gene
therapy
approaches.
Taken
together,
the
work
presented
in
this
thesis
aims
to
bring
us
closer
to
optimal
ex
vivo
manipulation
of
NK
cells
for
immunotherapy.
Clinical
trials
with
the
long‐term
expanded
NK
cells
as
well
as
further
preclinical
development
of
NK
cell
genetic
modification
processes
are
warranted.
