Preclinical safety and biodistribution of Sindbis virus measles DNA vaccines administered as a single dose or followed by live attenuated measles vaccine in a heterologous prime-boost regimen

Delivery strategies for novel vaccine formulations

A major challenge in vaccine design is to identify antigen presentation and delivery systems capable of rapidly stimulating both the humoral and cellular components of the immune system to elicit a strong and sustained immunity against different viral isolates. Approaches to achieve this end involve live attenuated and inactivated virions, viral vectors, DNA, and protein subunits. This review reports the state of current antigen delivery, and focuses on two innovative systems recently established at our labs. These systems are the filamentous bacteriophage fd and an icosahedral scaffold formed by the acyltransferase component (E2 protein) of the pyruvate dehydrogenase complex of Bacillus stearothermophilus.

Tumor-specific imaging through progression elevated gene-3 promoter-driven gene expression

Molecular-genetic imaging is advancing from a valuable preclinical tool to guiding patient management. The strategy involves pairing an imaging reporter gene with a complementary imaging agent in a system that can be used to measure gene expression, protein interaction or track gene-tagged cells in vivo. Tissue-specific promoters can be used to delineate gene expression in certain tissues, particularly when coupled with an appropriate amplification mechanism. Here we show that the progression elevated gene-3 promoter (PEG-Prom), derived from a rodent gene mediating the malignant phenotype, can be used to drive imaging reporters selectively to enable detection of micrometastatic disease in murine models of human melanoma and breast cancer using bioluminescence and radionuclide-based molecular imaging techniques. Because of its strong promoter, tumor specificity and capacity for clinical translation, PEG-Prom-driven gene expression may represent a practical, new system for facilitating cancer imaging and therapy.

Biodistribution, persistence and lack of integration of a multigene HIV vaccine delivered by needle-free intradermal injection and electroporation

It is likely that gene-based vaccines will enter the human vaccine area soon. A few veterinary vaccines employing this concept have already been licensed, and a multitude of clinical trials against infectious diseases or different forms of cancer are ongoing. Highly important when developing novel vaccines are the safety aspects and also new adjuvants and delivery techniques needs to be carefully investigated so that they meet all short- and long-term safety requirements. One novel in vivo delivery method for plasmid vaccines is electroporation, which is the application of short pulses of electric current immediately after, and at the site of, an injection of a genetic vaccine. This method has been shown to significantly augment the transfection efficacy and the subsequent vaccine-specific immune responses. However, the dramatic increase in delivery efficacy offered by electroporation has raised concerns of potential increase in the risk of integration of plasmid DNA into the host genome. Here, we demonstrate the safety and lack of integration after immunization with a high dose of a multigene HIV-1 vaccine delivered intradermally using the needle free device Biojector 2000 together with electroporation using Derma Vax™ DNA Vaccine Skin Delivery System. We demonstrate that plasmids persist in the skin at the site of injection for at least four months after immunization. However, no association between plasmid DNA and genomic DNA could be detected as analyzed by qPCR following field inversion gel electrophoresis separating heavy and light DNA fractions. We will shortly initiate a phase I clinical trial in which healthy volunteers will be immunized with this multiplasmid HIV-1 vaccine using a combination of the delivery methods jet-injection and intradermal electroporation.

Measles vaccination: new strategies and formulations

Measles is a highly contagious viral disease. With 1 million deaths reported in 1996, measles was the leading cause of vaccine-preventable deaths. However, in recent years, significant progress has been made in measles control, reducing deaths attributed to measles to 454,000 in 2004 and 242,000 in 2006. The main strategy behind this reduction has been the improvement of vaccination coverage and implementation of a second opportunity for immunization with the live-attenuated measles vaccine. The Measles Initiative, a partnership between the American Red Cross, CDC, UNICEF, WHO and UN Foundation, has had a significant role in this achievement. Here, we provide an overview of old and new vaccination strategies, and discuss changes in the route of administration of the existing live-attenuated vaccine, the development of new-generation nonreplicating measles virus vaccine candidates and attempts to use recombinant measles virus as a vector for vaccination against other pathogens.