Scientists have discovered triggers that influence whether CD4 immune cells ‘help’ or ‘kill’.

Helper T cells, also called CD4 T cells, play a crucial role in coordinating all the different cells in our complex immune systems. Their most well-known task is helping B cells make the antibodies needed to protect us from infection. But occasionally they act as ‘killer’ cells, tracking down and killing B cells that are hiding a fugitive such as a virus or are growing out of control, such as B cell lymphomas.

Research published in Cell Reports explains just how CD4 T cells switch to this killer role. Because there is no molecular marker that distinguishes killer CD4 T cells from their helper function, the scientists looked at the transcription of every gene in many individual CD4 T cells. This allowed them to identify the set of genes that program the killer activity.

The researchers were able to show in mouse models that CD4 T cells became helper or killer depending on the type of virus they have to fight.

Infection with retroviruses, the family HIV belongs to, instructs them to become helpers. In contrast, infection with adenoviruses, which cause the common cold and other illnesses in children, instructs them to become killers.

Taken from CrickNews Issue 28

Posted January 2017