Gr. Peplinski et al., CONSTRUCTION AND EXPRESSION IN TUMOR-CELLS OF A RECOMBINANT VACCINIA VIRUS ENCODING HUMAN INTERLEUKIN-1-BETA, Annals of surgical oncology, 2(2), 1995, pp. 151-159
Background: Human interleukin-1 beta (hIL-1 beta) injected intratumora
lly has demonstrated growth inhibition of transplanted subcutaneous tu
mors in mice, regression of metastatic lesions, resistance to tumor re
challenge, and increased survival. Vaccinia virus (VV) can be genetica
lly engineered to produce cytokines and may be an effective vector for
gene therapy of cancer. This study was designed to (a) construct a VV
expressing hIL-1 beta, (b) assess tumor cell infection in vitro with
this construct, (c) measure hIL-1 beta production, and (d) assess the
bioactivity of the secreted cytokine. Methods: The hIL-1 beta gene was
amplified from a plasmid clone using polymerase chain reaction (PCR)
and then cloned into a homologous recombination (HR) and expression ve
ctor, which was used to insert the hIL-1 beta gene into the VV genome.
Selection of the recombinant VV (VMJ601hIL-1 beta) was based on inact
ivation of viral TK and expression of beta-galactosidase. VMJ601hIL-1
beta infectivity and cytokine production was assessed by infecting tum
or cell lines and analyzing culture supernatants for hIL-1 beta. Bioac
tivity of the hIL-1 beta produced was demonstrated using an IL-1 depen
dent T helper cell line. Results: The hIL-1 beta gene was successfully
cloned into the VV genome by HR, which was confirmed by PCR. VMJ601hI
L-1 beta efficiently infected tumor cells, as shown by increased hIL-1
beta secretion (0 to > 500 ng/ml) and morphologic evidence of viral c
ytopathic effect, VMJ601hIL-1 beta-infected cells secreted large amoun
ts of hIL-1 beta (mean 772 ng/10(6) cells/24 h). The secreted hIL-1 be
ta was bioactive (mean bioactivity 6.8 x 10(8) U/mg of hIL-1 beta). Co
nclusions: (a) hIL-1 beta can be cloned into VV, (b) VMJ601hIL-1 beta
retains its infectivity, (c) a large amount of hIL-1 beta is secreted,
and (d) the secreted hIL-1 beta is bioactive, Recombinant VV may allo
w in situ cytokine gene delivery and expression in established tumors.