Each year in the United States, over 700,000 individuals acquire infections in hospitals or other healthcare facilities. These infections can often be attributed to microbes that are resistant to treatment. Despite the employment of cutting-edge sanitation practices, over 90,000 succumb to these infections annually.
The complexity of preventing such infections lies in the broad variety of bacteria and fungus causing hospital-acquired infections. The challenges extend further as developing new antimicrobial drugs is certainly a test, and tailoring individual vaccines for each type of microbe is virtually unpractical. However, researchers have recently discovered the possibility of innate immune cells retaining a memory that lasts for weeks to months, enabling them to respond more effectively to pathogens they have previously encountered. This revelation opens a window to design a vaccine that may broadly activate these immune cells, better defending the body during periods of heightened risk of infection.
A team of researchers at the University of Southern California, led by Jun Yan and Dr. Brad Spellberg, embarked on this path, conceptualizing protein-free vaccines to strengthen the innate immune system. The initial result of their work was a vaccine including three substances known for amplifying general immune response. The team found that this vaccine offered mice protection against the deadly MRSA infection, but not against pneumonia caused by another bacteria. Nonetheless, they continued refining this vaccine, incorporating a complex sugar molecule known as mannan. Once this modification was made, the vaccine protected mice from death caused by numerous microbes introduced via the bloodstream or lungs.
The researchers observed that monocytes and macrophages, both critical components of the innate immune defense, were essential for this protection. Further research indicated that the vaccine triggered specific changes in the gene activities of these immune cells, leading to a reduced inflammatory response to infections which in turn lessened the risk of sepsis, a lethal reaction of the human body to some hospital-acquired infections.
As an initiative towards human testing, the researchers proved that human macrophages could mimic the same gene activity changes as the mice when exposed to the vaccine. The collective efforts are being channeled towards testing the vaccine in human volunteers. This innovative approach to using our immune system to battle superbugs opens up new possibilities in infection prevention.