Klebsiella pneumoniae is a nasty, opportunistic bacteria that can cause pneumonia. It’s a tough one to fight, but now researchers at Tulane University have developed an inhalable vaccine that, in mouse tests, can invoke a strong immune response against several strains of the bacteria.
Infections of K. pneumoniae mostly occur in hospitals, leaving patients with a bout of pneumonia, or infections of the bloodstream or certain organs. Worryingly, the bug has developed resistance to a wide range of antibiotics, with some strains now shrugging off all known drugs. To make matters worse, hypervirulent strains are emerging and beginning to venture out of the healthcare system into the general population.
So for the new study, the Tulane team set out to develop a vaccine against the bacteria. Rather than being delivered intravenously, it can be inhaled in order to get it directly to the lungs, where the bacteria most often colonize.
The researchers started with a protein from K. pneumoniae called an outer membrane protein X, and combined it with a vaccine adjuvant called LTA1, derived from E. coli. In tests in mice, the inhaled vaccine induced a strong immune response, summoning CD4+ T cells, B cells and Th17 cells, which all have different roles in the protective process.
When the mice were then challenged with three different strains of K. pneumoniae, the vaccine protected them effectively. The team says that because the vaccine doesn’t work by targeting sugars on the surface of the bacteria, it could help against a wider range of bugs.
“The major cause of pneumonia in the world is Streptococcus pneumoniae, and there’s no reason why this technology theoretically couldn’t be used for that pathogen as well,” says Dr. Jay Kolls, corresponding author of the study. “I think this opens up a platform for really revisiting how we do vaccines for respiratory infections. Rather than getting an intramuscular injection, perhaps we should be doing intranasal or inhaled vaccines, which deliver the vaccine directly to the site of infection, where immune protection is needed most.”
Inhalable drugs are increasingly the subject of study for this reason – recent research has investigated them as potential treatments for lung cancer, cystic fibrosis, COVID-19, and other infections. Of course, the new work is still very preliminary at this stage, but it’s intriguing nonetheless.
The new research was published in the journal Science Immunology.
Source: Tulane University