Nature Immunology: Regulators of the immune system

But it doesn't work for all patients

In this study, immunologists led by Penn veterinarian Professor Christopher Hunter and doctoral student Joseph Perry found that blocking the activity of the checkpoint PD-L1 protein, which interacts with the T cell receptor PD-1, enhances the growth of T cells The activity of a subset is called effector regulatory T cells, or effector subsets

The findings shed light on the intricacies of how the body "regulates the regulators of the immune system," Hunter said

T cells are probably best known for their role in fighting infections and killing cancer cells

"You can think of tregs as the health and safety inspectors of the immune system," Hunter said

After exploring an unexpected discovery, researchers set out to learn more

Digging deeper into this surprising result, Perry, Hunter and colleagues realized that it was consistent with results recently reported by some cancer researchers

When the Penn-led team studied in the presence of Toxoplasma gondii infection, they found that the signaling molecule interferon gamma turns on PD-L1, which leads to a rapid decline in Treg numbers

"It seems that the ratio of effector T cells to Treg really matters," Hunter said

As researchers began to learn more about how Tregs were activated and operated during infection, they were curious whether this pathway would work when animals were in a normal, healthy state

"These results tell us that there are large numbers of activated PD-1-positive Treg cells that exist as a normal part of everyday life, helping to limit the immune system," Perry said

"We think these PD-1 cells are the most active Treg cells," Hunter said

In ongoing research, Hunt, Perry and colleagues continue to investigate this pathway, and others involving immune checkpoints

Journal Reference :

1. Joseph A.