Scientists have uncovered new evidence that strengthens the link between a host-cell gene called Apobec3 and the production of neutralizing antibodies to retroviruses.

Recent findings by medical researchers indicate that naturally occurring nanotubes may serve as tunnels that protect retroviruses and bacteria in transit from diseased to healthy cells — a fact that may explain why vaccines fare poorly against some invaders.

A cluster of antiviral genes in humans has likely battled retroviral invasions for millions of years.