Whooping cough, also known as pertussis, was formerly a leading cause of death in children in the United States and around the world before vaccines were introduced in the 1940s. In the decades since, the bacterial disease has been practically eradicated in the United States, with annual fatalities falling into the double digits. Now, new research from The University of Texas at Austin could aid in improving whooping cough vaccines to once again push this disease toward eradication by targeting two key weaknesses in the infection. But the disease has made a troubling comeback in recent years as vaccine coverage declined after the Covid-19 pandemic. In 2024, several outbreaks left public health officials and hospitals scrambling to accommodate a sudden influx of patients, primarily infants, who are often too young to be vaccinated and suffer the most severe symptoms. Against this backdrop, a team of researchers, including members of UT’s McKetta Department of Chemical Engineering and Department of Molecular Biosciences, has made significant strides in understanding and enhancing pertussis immunity. One of the things that makes pertussis infections dangerous is pertussis toxin (PT), a chemical weapon produced by the bacteria that weakens a patient’s immune response and causes many of the severe symptoms associated with whooping cough. The new research, described in a new study published in the Proceedings of the National Academy of Sciences, focuses on two powerful antibodies, hu11E6 and hu1B7, which neutralize the PT in different ways. Using cutting-edge cryo-electron microscopy approaches, the researchers identified the specific epitopes on PT where these antibodies bind. Epitopes are chemical targets the immune system can zero in on to fight pathogens. Hu11E6 blocks the toxin from attaching to human cells by interfering with sugar-binding sites, while hu1B7 prevents the toxin from entering cells and causing harm. These findings are the first to precisely map these critical regions, providing a blueprint to improve vaccines. “There are currently several promising new pertussis vaccines in the research and clinical trial phases,” said Jennifer Maynard, professor of chemical engineering at the Cockrell School of Engineering and corresponding author of the new study. “Our findings could be incorporated into future versions quite easily, improving overall effectiveness and longevity of protection.” She pointed to innovations like mRNA technology used in the Covid-19 vaccine, as well as breakthroughs in using genetic engineering on pertussis toxin (PTgen) to generate safer and more potent new recombinant acellular pertussis vaccines as technologies preserving neutralizing epitopes that can combine with her team’s new findings. “Training the immune system to target the most vulnerable sites on the toxin is expected to create more effective vaccines,” Maynard said. “And the more effective and longer-lasting a vaccine is, hopefully, the more people will take it.” In addition to helping guide future vaccine designs, the hu1B7 and hu11E6 antibodies themselves hold promise as therapeutic medicines for infected and high-risk infants.
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