Chimp viruses as a vector for human vaccines
Rome – A cold virus isolated from chimpanzees might work as an vector for human vaccines. Adenoviruses are principally suitable as vectors for vaccines for their ability to induce strong immune responses. But as most humans have already had contact with cold viruses, their trained immune system will dispose of the vectors before they have a chance to deliver their vaccine load.
Alfredo Nicosia of the Rome-based company Okairos may have found a way around that conundrum, as they report in Science Translational Medicine. The idea is that chimp adenoviruses might not be recognised by the human immune system but still retain their ability to induce a strong immune response. Nicosia and his team first isolated and characterised almost 30 different chimp adenovirus serotypes from some 1,000 stool samples. The defanged viruses were then tested for their immune response in mice, and the best ones were chosen for further development. “We’re working on different vaccines for Ebola, HIV, malaria, hepatitis C,” said Nicosia. “We wish to dedicate one specific chimpanzee derived serotype to one specific vaccine target” to avoid the possibility that antibodies induced by one vaccine vector might blunt the effect of another, he explained. Paul Klenerman of the University of Oxford, who is looking for a vaccine against Hepatitis C, already tried the adenoviruses on human volunteers. The chimp adenovirus-based HCV vaccine induced a strong T cell response. A second trial in high-risk individuals—intravenous drug users—has already started.