By creating a molecular clone of infectious HIV and inserting a special gene into its genetic code, scientists were able to film how the virus spreads directly from infected CD4 cells to uninfected ones, The Daily Telegraph reports. Researchers hope that the digital video will lead to new breakthroughs in treatment and vaccine development.

According to the article, the video showed that when an infected CD4 cell (a.k.a. T-cell) comes into contact with a healthy one, it forms a bridge called a virological synapse. Because the inserted gene used in the study turned HIV fluorescent green when exposed to blue light, scientists were able to observe the viral particles entering the healthy cell.

While researchers discovered that HIV travels from cell-to-cell via virological synapses in 2004—in addition to migrating freely between cells—they did not yet know why the process was so effective. This video illustrates that cell-to-cell transfer helps the virus avoid immune system detection in ways free-circulating virus does not.

“Direct T-cell-to-T-cell transfer through a virological synapse is a highly efficient avenue of HIV infection, and it could be the predominant mode of dissemination,” said study coauthor Benjamin Chen, assistant professor of medicine and infectious diseases at the Mount Sinai School of Medicine in New York City.

Watch the video below: