Dr. Hall developed vaccine technology at The Scripps Research Institute. Prototype vaccines have been made against Respiratory Syncytial Virus, Hepatitis B and C, H1N1 (SARS) and other Coronaviruses, Anthrax, Plague, West Nile Virus and Ebola. The figure below shows the steps involved in devloping an Ebola vaccine (NoBola) using this technology.

INTRODUCTION

Stem cells can express therapeutic genes for cancer therapy.
The ability of MaxGelTM to increase cell proliferation and tumor
formation and improve subsequent delivery of therapeutic stem cells for the treatment of prostate cancer was studied.
In order to influence tumor formation, xenografts were induced
in nude mice by subcutaneous inoculation of PC3 human bone
metastatic prostate cancer cells with and without MaxGelTM.
Mesenchymal stem cells were engineered with the yeast
cytosine deaminase gene that converts non-toxic 5-
fluorocytosine into the highly toxic anti-tumor 5-fluorouracil,
which selectively targets tumor cells. This engineered stem cell
line (CD-MSC) was delivered into nude mice after tumor
formation with and without MaxGelTM to determine the degree
of tumor regression.

RESULTS

After 14 days, MaxGelTM (1 mg/ml) caused significantly larger
tumors in mice than did PC3 tumor cells alone.
Following delivery of 2 x 106 CD-MSC delivered intravenously
into nude mice (n=9 each group) either alone or in conjunction
with MaxGelTM, it was determined that MaxGelTM was able to
cause a significant reduction of tumor size due to its ability to
augment delivery of CD-MSC to the tumor site and facilitate
tumor killing by the therapeutic stem cells.


CONCLUSION

MaxGelTM promoted significantly greater proliferation of tumor
cells in a xenograft tumor model in nude mice. Even in the
presence of this increased tumor mass, MaxGelTM provided a
superior support matrix for therapeutic stem cell growth and
differentiation, resulting in greater tumor necrosis than using
therapeutic stem cells alone.

Stephen Hall, PhD

Vaccines

Stem Cells & Biomaterials in Cancer Research