Researchers at the Francis Crick Institute have shown that water influx is necessary for immune cells called T cells to activate and divide in response to a threat.
T cells defend against infections and other threats to the body. Small T cells are constantly moving around in a resting state, but in the presence of antigens – foreign material from viruses and bacteria – T cells switch on, enlarge in size and start dividing very quickly. This creates a batch of T cells able to recognise and destroy that particular antigen.
In research published this week in Nature Communications, the team at the Crick found that a protein called WNK1 causes water to enter through channels on the T cell surface and is required to kick-start this process. This follows research from the lab in 2023, showing that WNK1 is necessary for T cell migration.
In the new study, the scientists compared what happened when mouse T cells, with and without WNK1, were triggered by a lab technique mimicking an infection.
They found that in mice with WNK1-deficient T cells, the number of T cells responding to the infection was greatly reduced and the mice were unable to produce antibodies, proteins which are a hallmark of an immune response that depends on T cells.
The team also observed that WNK1 activity causes ions – sodium, potassium and chloride – to enter the cell. Water then follows by osmosis, through channels on the membrane called aquaporins.
Credit: The Francis Crick Institute
Image Credit: Colorised scanning electron micrograph of a T cell. Credit: NIAID.