Re-purposed drug triggers immune system to kill bacteria

An anti-histamine drug could have a further purpose as an alternative to antibiotics in treating bacterial infections, a study involving Roslin researchers has shown.

The treatment,  known as clemastine, can activate immune cells called macrophages to kill bacteria.

The discovery offers a potential way to limit the use of antibiotics, as bacterial resistance to the drugs increases worldwide.

A team of researchers led by the University of Edinburgh’s Institute for Regeneration and Repair studied how macrophage cells can engulf and kill the bacterial pathogen Streptococcus pneumoniae.

They identified three macrophage genes of interest - the gene ACOD1 produces an acid which directly kills bacteria, NAMPT helps macrophages generate energy, and the gene P2RX7 regulates the killing of bacteria via digestion after they have been engulfed.

Researchers then studied the anti-histamine drug clemastine, which has a known side effect of activating the bacterial-killing P2RX7 gene.

In studies on mice and zebrafish larvae, the team found that clemastine could increase the ability to kill the bacteria without the need for antibiotics.

Roslin researchers contributed to different aspects of the study, including analysis of the bacterial genetic code.

The team is applying this strategy to other bacterial infections, and will be investigating ways to study clemastine as an alternative or addition to conventional antibiotics for people.

This work was funded by Wellcome Trust, UK Research and Innovation Medical Research Council, Chief Scientist Office Scotland, European Crohn’s Colitis Organisation, National Science Centre of Poland and UK Biotechnology and Biological Sciences Research Council.

The study was published in Science Advances.

Image credit: F Studio/Adobe.