'Bionic Assassins' Provide Breakthrough in Wiping Out HIV Infected Cells

by Hannah Punitha on Nov 10 2008 5:05 PM

An international research team has achieved a breakthrough in developing 'bionic assassins' that are capable enough to recognize HIV-1 strains that evade immune system, thereby opening up new avenues for developing novel AIDS treatments.

The team, comprising experts from Universities of Cardiff and Pennsylvania, say that they have engineered immune cells to act as "bionic assassins".

Natural T cells identify their targets through weak molecular interactions interceded by the T cell receptor.

Led by Professor Andy Sewell from Cardiff University, United Kingdom, the team have engineered and tested a killer T-cell receptor that is able to locate different HIV masquerades that prevents them from being detected.

During the study, the researchers were able to isolate a group of T cell receptor encoding genes that bind to HIV-1 about 450-fold more strongly.

The receptors were then connected to killer T-cells to develop genetically engineered "bionic assassins" that would wipe out HIV-infected cells in culture.

"Not only could T cells engineered to express the strongly binding T cell receptor see HIV strains that had escaped detection by natural T cells, but the engineered T cells responded in a much more vigorous fashion so that far fewer T cells were required to control infection," Nature magazine quoted co-senior author James Riley, PhD, Research Associate Professor of Pathology and Laboratory Medicine at Penn, as saying.

"When the body mounts a new killer T-cell response to HIV, the virus can alter the molecular fingerprint that these cells are searching for in just a few days," said Professor Andy Sewell from Cardiff University, co-lead author of the study and long-term collaborator with Adaptimmune.

"It's impossible to track and destroy something that can disguise itself so readily. As soon as we saw over a decade ago how quickly the virus can evade the immune system we knew there would never be a conventional vaccine for HIV," he added.

"The T-cell receptor is nature's way of scanning and removing infected cells - it is uniquely designed for the job but probably fails in HIV because of the tremendous capability of the virus to mutate," said Dr Bent Jakobsen, co-lead author and Chief Scientific Officer at Adaptimmune Ltd, the company which owns the technology.

"In the face of our engineered assassin cells, the virus will either die or be forced to change its disguises again, weakening itself along the way," Sewell added.

The study is published online in the journal Nature Medicine.