The research team has identified seven different receptors on T cells that can suppress immune responses during a long battle with an infectious pathogen or against developing cancer.
Study's lead author, E. John Wherry, Ph.D., an assistant professor in Wistar's Immunology Program said that chronic over-stimulation of the immune system can 'exhaust' immune cells rendering them ineffective.
The key finding is that these new receptors likely control different aspects of T cell responses, such as division or expansion, controlling viral replication, and local killing of infected cells versus secretion of long-range active antiviral proteins.
"This amount of control over T cells' response is remarkable. It suggests that layers of negative regulation exist on exhausted T cells from co-expression of multiple inhibitory receptors," Nature quoted him as saying.
"My bet is that these receptors inhibit different aspects of the T cells' response, but that the net result of their activation is to turn specific T cell populations off.
"We are starting to see a picture emerging of a really tuneable array of inhibitory receptors expressed on T cells.
"That suggests it may be possible to not only dramatically enhance antiviral or antitumor T cell responses, but also to fine tune which response you want to enhance in order to reverse T cell exhaustion and continue fighting an infection or disease.
"This presents us with a great clinical opportunity. T cells have a lot of weapons at their disposal to control viral infection and most of them are disarmed when these cells become exhausted.
"It may be possible to selectively rearm T cells while generally reinvigorating them," he added.
The study appears in journal Nature Immunology.