New vaccine technology utilising weakened DNA viruses

A new method of vaccine technology that employs weakened viruses has been developed to target DNA viruses that reproduce by making copies of their own DNA molecules, utilising a virus with altered DNA to fight against them.

The vaccine functions by producing an attenuated version of a mouse cytomegalovirus, which has been rendered so it cannot reproduce or replicate within a cell. Because of its inability to replicate, the virus is restricted to its site of administration as it cannot produce infectious viral material. Researchers discovered that when injected into animals, the weakened viral particles stimulated a host’s immune system into recognizing the particles as foreign, producing an immune response that eliminates the virus when detected. 

“We have found that this method is safe – the attenuated virus infects certain cells without proliferating beyond that, and alerts the host to produce specific neutralising antibodies against it,” commented Dabbu Jaijyan, a researcher at Rutgers New Jersey Medical school. “We see this as a novel method that we hope will accelerate vaccine development for many untreated viral infections in humans and animals.” 

Because the vaccine specifically targets DNA viruses such as cytomegalovirus, chicken pox, and herpes – viruses that make copies of their DNA molecules to reproduce – the vaccine method has been termed a live-attenuated DNA virus vaccine as it uses an altered DNA virus against the infections. The method is capable of quickly generating live-attenuated viruses that cannot replicate, and could potentially accelerate vaccine development for DNA virus diseases. In mice studies, researchers at Rutgers demonstrated that the method was effective against several DNA viruses, including both human and mouse cytomegalovirus and herpes simplex virus 1 and 2. While not all viruses replicate through DNA copying (such as SARS-CoV-2, which replicates through its RNA), this vaccine method works for DNA viruses as the viral particles are treated with a DNA-binder. The binder latches onto any organism’s DNA, including the viral DNA, and blocks reproduction. 

When testing the method against cytomegalovirus, the team purified samples of the virus grown in their lab and bathed them in centanamycin. This mixture was injected into mice but the weakened virus that infected the cells did not spread. The mice’s immune system then produced antibodies to eliminate the virus and prevent infection. Cytomegalovirus is a common virus for individuals of all ages, however those who are immunocompromised and organ transplant patients can suffer severe symptoms. The virus can be spread through bodily fluids and is the leading cause of birth defects in newborns through congential infection. 

Researchers hope to eventually test the method on humans, as well as model test for other medically important viruses. 

“One of the major advantages of our technology is the safety offered by the robust inhibition of virus replication and that no progeny viruses are produced... Our technology can be easily applied to any DNA virus to generate live-attenuated replication defective viruses for vaccine development,” Jaijyan stated. 

Source: Rutgers Scientists Produce “DNA Virus Vaccine” to Fight DNA Viruses | Rutgers University