A vaccination method that maintains a toxin’s structure results in improved vaccination efficacy, reports a study published online this week in Nature Nanotechnology.
Vaccines based on inactivated toxins are used to induce immunity against bacterial infections, such as those from Escherichia coli, without causing a full-blown illness in patients. The toxin is usually inactivated chemically or by heat; however, this results in a modification of its structure that can lead to inefficient vaccination.
Liangfang Zhang and colleagues engineered a methodology to preserve the toxin structure of staphylococcal alpha-haemolysin by capturing the toxin using a nanoparticle coated with a red blood cell membrane. The capturing process ensures the neutralization of the toxin’s virulence, while maintaining the efficiency of inducing an immune response.
Zhang and colleagues compared the safety and efficacy of these vaccines by injecting either the nanoparticle-based vaccine or control vaccines with thermally inactivated toxins into the skin of mice. They found that the nanoparticle-based vaccine induced higher concentrations of antibodies than the control vaccine, and produced antibodies that are more able to neutralize the toxin when exposed to it. As a result of the increased efficacy, the survival rate of mice vaccinated with the control was 90% compared with a survival rate of 100% for those injected with the nanoparticle-based vaccine.