Colon cancer cell vaccine prepared with replication-deficient vaccinia viruses encoding B7.1 and interleukin-2 induce antitumor response in syngeneic mice

Abstract

A replication-deficient recombinant vaccinia virus, NYVAC, was developed by deleting 18 open reading frames in the vaccinia virus genome. Recombinant NYVAC, encoding the murine T cell co-stimulatory gene B7.1 (CD 80) (NYVAC-B7.1) and the murine interleukin-2 gene (NYVAC-IL-2), were prepared and the expression of B7.1 and the secretion of IL-2 were respectively confirmed in vitro. The use of these viruses to prepare a potent tumor cell vaccine was studied in a syngeneic murine CC-36 colon adenocarcinoma model. Mice were immunized on days 1 and 8 with 10(6) irradiated CC-36 cells that were infected with 10(7) plaque-forming units of either NYVAC-B7.1, NYVAC-IL-2 or a control virus, NYVAC-HR, which encodes a vaccinia virus host-range gene. These mice were then challenged with 10(8) viable CC-36 tumor cells on day 15. All mice (10/10) in a group that had received no vaccination and all mice (20/20) in a group that had received a control vaccine of CC-36/NYVAC-HR developed tumor 4-weeks after tumor cell challenge. Interestingly, only 16/20 mice in a group that had received CC-36/ NYVAC-B7.1 showed the development of tumor after the same interval. The protection against tumor development and the reduction in tumor burden (as mean tumor diameter, 4 weeks after tumor challenge) were significant in this group when compared to groups that were either unvaccinated or vaccinated with CC-36/NYVAC-HR (mean tumor diameter = 6.51+/-3.2 mm compared to 26.5+/-0.9 mm or 26.2+/-1.8 mm respectively) (P = < 0.05). The protection against tumor in a group of mice that received CC-36/ NYVAC-IL-2 vaccination was similar to that in the unvaccinated group or the group receiving a CC-36/NYVAC-HR control vaccination. However, in a survival experiment, mice that received either CC36/NYVAC-B7.1 or CC-36/ NYVAC-IL-2 vaccination on the day of tumor transplantation survived significantly longer than mice that had not been vaccinated (median survival 60+ days, 60+ days or 23.5 days respectively) (P = < 0.05). Interestingly, when a therapeutic tumor vaccination was performed on day 4 after tumor transplantation, mice that had been vaccinated with either CC36/NYVAC-B7.1 or CC-36/NYVAC-IL-2 did not show an improved survival when compared to mice in the control that had not been vaccinated (median survival 28 days compared to 26 days or 25 days respectively). However, mice that had received a therapeutic vaccination with CC-36 cells infected with both NYVAC-B7.1 and NYVAC-IL-2, 4 days after tumor transplantation, survived significantly longer than control mice that had not received any vaccination (median survival 29.5 days compared to 25 days respectively) (P<0.05). These results suggest that a replication-deficient recombinant NYVAC encoding the B7.1 gene and NYVAC encoding the IL-2 gene can be used to produce an effective vaccinia-virus-augmented tumor cell vaccine.

Differential Induction of Apoptosis, Interferon Signaling, and Phagocytosis in Macrophages Infected with a Panel of Attenuated and Nonattenuated Poxviruses

“…NYVAC is an attenuated derivative of the VACV Copenhagen strain (CopV), from which 18 open reading frames (ORFs) were specifically deleted from the parental viral genome, including those involved in host range, virulence, and pathogen-esis (13). NYVAC-derived vectors are able to express antigens from a broad range of species (13) and have been used as recombinant vaccines against numerous pathogens and tumors (1,(14)(15)(16), and phase I/II clinical trials using NYVAC against HIV-1 have shown strong and specific immunogenicity and a good safety profile (17). The most frequently studied nonattenuated VACV strain is Western Reserve (WR), a mouse brain-passaged derivative of the New York Board of Health (NYBH) vaccinia virus (18), one of the most widely used vaccinia viruses in the smallpox eradication program and the basis of the only commercially approved smallpox vaccine (Dryvax) available for limited use in the United States (19).…”

Host Response to the Attenuated Poxvirus Vector NYVAC: Upregulation of Apoptotic Genes and NF-κB-Responsive Genes in Infected HeLa Cells

“…This vector has been applied as a recombinant vaccine delivery system in animal models and target species, including humans (34,37). NYVAC-based vectors have been analyzed as vaccines for several tumors (23,46) and are protective against pathogens such as retroviruses (5, 10, 31), Japanese encephalitis virus (24), and Plasmodium falciparum (34). The potential use of variola virus as a biological weapon requires the development of safer smallpox vaccines, using attenuated VV strains such as MVA and NYVAC (4, 9).…”

“…Total proteins (100 g) were separated by SDS-PAGE, transferred to nitrocellulose, and immunoblotted at various times (6 and 16 hpi) with an anti-caspase-9 antibody (Oncogene) that recognizes the procaspase and the cleaved active form of caspase-9. Caspase-9 presented a proform (46 (Fig. 5A, lower panels).…”

“…NYVAC-derived vectors are able to express antigens from a wide range of species (50). A number of examples have been reported, using NYVAC as a recombinant vaccine delivery system against pathogens and tumors (5,10,31,46). Clinical trials using NYVAC-based vectors show a good safety profile, with induction of high levels of immunity against heterologous antigens (24, 34).…”

Hybrid cell vaccination for cancer immune therapy: First clinical trial with metastatic melanoma

“…Cell surface co-stimulatory molecules such as B-7 have been introduced into tumour cells to enhance their co-stimulatory capacity (Chen et al, 1992;Raes et al, 1998) but were found to be of similarly restricted effectiveness. In consequence, combinations of cytokines and cell surface co-stimulatory molecules are now being evaluated in pre-clinical and clinical studies (Sivanandham et al, 1998).…”