NIAID supports research on how Bordatella pertussis causes illness, particularly the role of various proteins and toxins produced by the bacteria and how the body responds to them. During infection, these toxins are released causing damage to the respiratory tract and inflammation that can persist for weeks or months. To determine the range of effects of pertussis toxin (PT), NIAID-funded researchers at the University of Maryland School of Medicine genetically modified B. pertussis to be deficient in PT and compared the course of infection in mice infected with the modified bacteria to that of mice infected with the unmodified version. They found that higher levels of PT were associated with increased inflammation and longer-lasting, more severe damage to the lungs and airways.
Researchers are also studying a toxin called adenylate cyclase toxin (ACT), with the hope of modifying it to stimulate the immune system without causing illness as part of a next-generation pertussis vaccine. In May 2013, NIAID grantees at the University of Virginia published a study that measured the quantities of ACT at various stages of infection. In addition to helping scientists understand the levels of toxin involved during pertussis infection and the immune system response, the techniques used in this study may be applied to other toxins and other diseases.
In addition, NIAID supports genetic research to better understand the evolution of B. pertussis and the related bacterium B. parapertussis, both of which are known to cause pertussis disease. Scientists suspect that other Bordetella species may have a role in causing milder infections and that by exchanging genes with B. pertussis and B. parapertussis, these species might enable their evolution and adaptation to humans and other animals. Current diagnostic tests for pertussis detect only B. pertussis and B. parapertussis infections. By better understanding the genetics of pertussis bacteria, scientists hope to develop more comprehensive diagnostics and vaccines.