T cells modified using the Sleeping Beauty gene transfer system may help fight infections caused by invasive Aspergillus fungus.
Sleeping Beauty is already being used to create chimeric antigen receptor (CAR) T cells to treat leukemias and lymphomas.
And now, researchers have found the system may also be effective for combatting fungal infections that can be deadly for immunosuppressed patients, such as those receiving transplants to treat hematologic cancers.
“We demonstrated a new approach for Aspergillus immunotherapy based on redirecting T-cell specificity through a CAR that recognizes carbohydrate antigen on the fungal cell wall,” said study author Laurence Cooper, MD, PhD, of MD Anderson Cancer Center in Houston, Texas.
He and his colleagues described this approach in the Proceedings of the National Academy of Sciences.
Dr Cooper originally learned about Sleeping Beauty gene transfer from a study published by Perry Hackett, PhD, a professor at the University of Minnesota who created the process.
The system is named Sleeping Beauty because Dr Hackett was able to “awaken” an extinct transposon—DNA that can replicate itself and insert the copy back into the genome—and package it with a gene he wants to transfer into a plasmid. An associated transposase enzyme binds to the plasmid, cuts the transposon and gene out of the plasmid, and pastes it into the target DNA sequence.
Dr Cooper and his colleagues have found they can use this process to engineer T cells that target sugar molecules in the Aspergillus cell walls, thereby killing the fungus.
Specifically, the team adapted the pattern-recognition receptor Dectin-1 to activate T cells via chimeric CD28 and CD3-ζ (D-CAR) upon binding with carbohydrate in the cell wall of Aspergillus germlings. They used Sleeping Beauty to modify the T cells to express D-CAR.
These D-CAR+ T cells exhibited specificity for β-glucan, and this inhibited Aspergillus growth both in vitro and in vivo. Furthermore, the researchers found that treating D-CAR+ T cells with steroids did not significantly compromise antifungal activity.
“The [D-CAR+ T cells] can be manipulated in a manner suitable for human application,” Dr Cooper said, “enabling this immunology to be translated into immunotherapy.”
