The tip of an immune molecule known for its skill at fighting cancer may also help patients survive pneumonia, scientists report.

A synthesized version of the tip of tumor necrosis factor appears to work like a doorstop to keep sodium channels open inside the air sacs of the lungs so excess fluid can be cleared, according to a study published in the American Journal of Respiratory Critical Care Medicine.

This TIP peptide is attracted to the sugar coating at the mouth of the sodium channel. Once the two connect, they move inside the small but essential number of cells that help keep the lungs clear by taking up sodium, say researchers.