SAINT-Vivo enables in vivo transfection and vaccination
SAINT-Vivo is an optimised version of the SAINT-18 cationic lipid, which has been used by several groups of researchers for in vivo application as a delivery agent for DNA.
The group of C.N.Kuo et al. has shown non-inflammatory corneal transfection in rats. In one of their publications they demonstrate inhibition of corneal neovascularization with a plasmid encoding pigment epithelium-derived factor (p-PEDF), delivered by SAINT-18, in an experimental model of rat corneal angiogenesis. Yet another publication examines the combination of a recombinant humanized monoclonal antibody to VEGF with p-PEDF/SAINT-18. Together, this work demonstrates that a combination of antibody and gene therapy using SAINT-18 may have potent and prolonged anti-angiogenic effects, thus providing a potential new therapy for severe complications of ischaemic ocular diseases caused by neovascularisation.
In the field of DNA vaccination, Endmann et al. have shown SAINT-mediated delivery of a gene expression vector coding for hepatitis B virus surface antigen (HBsAg). Upon intradermal injection of this DNA vaccine, a dose-dependent antibody response was elicited in mice. Another publication by the same group demonstrated that when administered in combination with SAINT-18, the expression vector is found in significantly larger amounts in draining lymph nodes compared to the same vector without SAINT-18. Furthermore, the use of SAINT-18 resulted in greater antigen expression, and the combination of SAINT-18 with the gene expression vector was well tolerated in mice and rats. In a study in pigs, Endmann et al. show that a SAINT-18 formulated DNA vaccine at a relatively low dose elicits an immune response similar to a normal dose of a commercial, licensed aluminum hydroxide-adjuvanted protein vaccine. After three vaccinations, the SAINT-18 formulated DNA vaccine induces a specific antibody response at a level considered protective. In conclusion, a SAINT-formulated DNA vaccine may provide a safe and effective alternative to current hepatitis B vaccines.
A research group at the university of Hannover has shown the application of SAINT-18 as a delivery agent in therapeutic DNA vaccination therapy against equine melanoma. Grey horses vaccinated thrice with DNA vectors encoding equine IL-12 and IL-18 display a significant decrease in tumour burden.
In conclusion, these animal studies demonstrate that SAINT-18 is an excellent delivery vehicle for gene expression vectors for in vivo applications, including DNA vaccines that elicit effective immune responses against viruses and cancer.