Vaccine Breakthrough for Toxoplasmosis

Novel DNA vaccine technology generates an immune response to a birth-defect-causing pathogen in lab mice, according to Researchers at the College of Veterinary Medicine of Nanjing Agricultural University, China.

The pathogen is called Toxoplasma gondii. It causes the chronic infection Toxoplasmosis that afflicts a wide range of hosts, including humans and domestic mammals.The infection can lead to birth defects in pregnant hosts; there are currently limited forms of treatment, for infected individuals, and no vaccines are available.

In the journal, Frontiers in Immunology, researchers described how they created the novel vaccine, which was used in their study. To deliver the vaccine, they utilized nanospheres of non-toxic, biodegradable polymers. These tiny spheres fused with the mouse cells and released the genetic information of the vaccine into the cell. The genetic information was a programmable ring of DNA, a plasmid, which worked with the mouse cell to make the antigen- a small piece of the parasite unique to it- which is responsible for kicking off the immune response.

Researchers reported a strong immune response with their vaccine. Compared to those who didn’t receive the vaccine, the vaccinated mice had a greater increase in cellular communication and specific immune cells to fight the disease, all signs of a healthy immune response. Further, when exposed to a lethal dose of Toxoplasma gondii, those who had the vaccine had a two-fold difference- 100,000,000 to 50,000,000- in the number of pathogens, compared to the control group.

Despite their experiment’s success, researchers noted its limitations. They cited desires to increase the number of plasmids per nanosphere, generating a stronger immune response. Most importantly, they cautioned that this was an animal trial and has many more steps in vaccine development before use in humans, but they are confident that this is a first step in the right direction to defeating Toxoplasmosis.