New photoimmunotherapy technique targets periodontitis while preserving good bacteria

A near-infrared photoimmunotherapy technique first developed for cancer treatment has been adapted to selectively target periodontitis without a detrimental impact on the oral microbiome.

The method uses an antibody-dye compound that binds to target cells, activated by near-infrared light. In experiments, it bound to Porphyromonas gingivalis – a key pathogen that triggers periodontitis inflammation – while having no effect on human cells and harmless bacteria.

Researchers from Nagoya University have published an exploration of the potential of photoimmunotherapy for periodontitis treatment in the Journal of Translational Medicine. When tested on mice, the technique significantly reduced alveolar bone loss and improved the oral microbiome.

What benefits does photoimmunotherapy have over existing periodontitis treatments?

Existing treatments for periodontitis such as antibiotics and antimicrobial photodynamic therapy (aPDT) are not selective in the microorganisms they destroy. This means they often eliminate beneficial oral bacteria alongside harmful pathogens.

Kazuhide Sato, lecturer at Nagoya University and one of the paper’s corresponding authors, said: ‘These approaches often disrupt the entire oral microbial ecosystem and can also release lipopolysaccharide (LPS), an endotoxin that may exacerbate inflammation.

‘Results demonstrated that, unlike antibiotics or standard light therapy, this approach selectively removes the primary pathogenic species while preserving the remainder of the oral bacterial community.’

What’s next?

The researchers note that periodontitis can be caused by many different pathogens, so targeting one may not be enough. In future research, they hope to use artificial intelligence to identify other important bacteria in inflammatory processes and develop more precise treatments.

As periodontitis has been linked with systemic health problems such as diabetes, the paper’s authors also hope their research could help identify patients who are the most likely to benefit from targeted treatments.

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