DNA Vaccine for Malaria Demonstrates Ability to Kill Infected Cells

Anopheles gambiaeA new potential vaccine for malaria is gaining media attention after successful pre-clinical trials in small animals and non-human primates.  Until now, the most effective malaria vaccine in human clinical trials has been GSK’s RTS,S vaccine.  Their vaccine demonstrated a 50% efficacy in children between the ages of 5 and 17 months and only a 30% efficacy in infants aged 6 to 12 weeks.

However, a recent article published in the American Society for Microbiology’s peer-reviewed journal, Infection & Immunity, titled “Inducing humoral and cellular responses to multiple sporozoite and liver-stage malaria antigens using pDNA” introduces a vaccine that could give the RTS,S vaccine a run for its money.

The vaccine in from this study was developed by Inovio Pharmaceuticals (Blue Bell, PA) and is one of their advanced SynCon® DNA Vaccines.  Along with their collaborators, the researchers at Inovio designed the DNA vaccine to incorporate four sporozoite and liver-stage malaria antigens that play a critical role in the control or elimination of malaria infection.  The doses were administered using their CELLECTRA® electroporation device which injects the vaccine into the tissue and then sends out small electrical pulses.  The pulses create small pores in the cell membranes of nearby cells that allow the plasmid DNA to enter.

Dr. J. Joseph Kim, President and CEO of Inovio, said, “Published data from two clinical studies has demonstrated that Inovio’s products generated best-in-class T-cell immune responses.  Using the same synthetic vaccine technology that produced clinical candidates against HPV, HIV, and influenza and achieved potent antibody and T-cell immune responses against these targets, we have now generated strong immunology data with our malaria vaccine in non-human primates.  We are excited to advance toward the very important healthcare goal of conquering malaria.”

Malaria Life Cycle - NIAID

The vaccine demonstrated strong and durable antibody and T-cell immune responses.  Not only that, the vaccine-produced T-cells also displayed the ability to kill and eliminate malaria-infected cells.  Additionally, the researchers found evidence of vaccine-induced CD8+, or “killer T-cells”, in the liver which have proven essential for rapid elimination of liver-stage malaria parasites.  Confident in their data thus far, Inovio has announced they will be initiating a Phase I/IIa clinical trial of the investigational vaccine in 2014.  Approximately 30 individuals will be enrolled to participate in this “challenge trial” involving controlled human malaria infection.

In addition to their malaria vaccine, Inovio has achieved strong results from a Phase I trial of their therapeutic vaccine against HPV-caused pre-cancers and cancers, as well as their universal flu vaccine.

(For more information on malaria and other malaria vaccines undergoing development – click here)

 

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What advancement in the field of DNA Vaccines do you think has made the biggest impact?  Do you think there is anything else that could provide more effective delivery of DNA Vaccines than electroporation?  Tell us what you think in the comments below!