A new vaccine, tested in mice, has demonstrated the potential to provide broad protection against a wide range of respiratory viruses, bacteria, and even allergens, researchers at Stanford Medicine announced Wednesday.
The vaccine, detailed in a study published in the journal Science, differs fundamentally from traditional vaccines, which target specific pathogens. Instead of training the immune system to recognize a single “wanted poster” for a virus or bacterium, this new approach stimulates a more generalized state of heightened alert, preparing immune cells to respond rapidly to a diverse array of threats.
The research team, led by Bali Pulendran, PhD, professor of microbiology and immunology at Stanford Medicine, and Haibo Zhang, PhD, a postdoctoral scholar in Pulendran’s lab, delivered the vaccine intranasally – via a nasal spray – to mice. The study showed the vaccinated mice were protected against SARS-CoV-2 and other coronaviruses, Staphylococcus aureus and Acinetobacter baumannii (common hospital-acquired infections), and house dust mites, a common allergen. Protection lasted for several months.
“This has worked for a remarkably wide spectrum of respiratory threats the researchers have tested,” said Pulendran. The vaccine utilizes a combination of molecules that mimic signals the body naturally produces when under attack, activating innate immune cells like macrophages. This activation also enhances the ability of the respiratory system’s epithelial cells to resist infection, according to the study.
The vaccine’s formulation includes three components that target the innate immune system, combining toll-like receptor (TLR) 4 and 7/8 ligands with a model antigen, ovalbumin, delivered in a liposomal formulation. Vaccinated mice exhibited rapid pathogen-specific T cell and antibody responses and formed ectopic lymphoid structures in the lung, indicating a robust immune response.
Researchers previously observed similar broad protective effects with the Bacillus Calmette–Guérin (BCG) vaccine, which activates the innate immune system. This latest study builds on that understanding, aiming to harness the power of the innate immune system for broader respiratory protection.
Even as the results are promising, the consequences of broadly stimulating the immune system beyond its normal state remain unknown and will require careful evaluation in human trials. The potential for such a vaccine, if successfully translated to humans, is significant, potentially replacing multiple annual jabs for seasonal respiratory infections and providing a rapid response capability for emerging pandemic viruses.
