A new type of cholera vaccine can provide much longer protection

The virus-like particle (Qβ-OSP conjugate), which reflects a polysaccharide from the bacterium Vibrio cholerae, creates a strong, long-lasting immune response in mice. Credit: Adapted from ACS Infectious Diseases 2022, DOI: 10.1021 / acsinfecdis.1c00585

Cholera is a diarrheal disease caused by bacteria with a high degree of transmissibility Vibrio cholerae, kills tens of thousands of people worldwide each year. Current vaccines only work for 2-5 years and they do not work very well on young children. Now researchers report in Infectious diseases of ACS developed a new type of cholera vaccine consisting of polysaccharides reflected on virus-like particles. The vaccine caused a prolonged antibody reaction B. cholera y mice.

Modern cholera vaccines contain killed or weakened B. cholera bacteria and administered orally. They offer the lowest level and duration of protection in young children who are usually cholera in endemic countries. The immune system produces antibodies against O-specific polysaccharide (OSP) on the surface B. cholera, but this polysaccharide in isolation does not produce a strong, sustained immune response. Peng Xu, Edward Ryan, Xuefei Huang and his colleagues wondered whether attaching OSP to virus-like particles could trigger stronger and longer-lasting immunity.

Thus, the researchers developed a method for efficiently binding multiple copies of OSP to Qβ, a virus-like particle that infects bacteria. Modified virus-like particles were recognized by antibodies in blood taken from cholera patients who were cured, but not in patients with typhoid fever, another bacterial disease. The team then immunized the mice with Qβ-OSP, noting that the three doses elicited a strong antibody response that persisted for at least 265 days after the first dose. The immunized mice had antibodies that recognized OSP from natural lipopolysaccharide B. cholera. When researchers mixed serum antibodies from mice with other immune system proteins that kill bacteria, and with live B. cholera, antibodies from two of the five mice caused more bacterial death than antibodies from mice immunized with Qβ alone. According to the researchers, the virus-like particle can mimic natural bacteria by presenting several copies of OSP on its surface, and it requires further evaluation as a new generation cholera vaccine.

Reference: “Virus-like particles Vibrio cholerae O-specific polysaccharide as a potential cholera vaccine” February 16, 2022, Infectious diseases of ACS.
DOI: 10.1021 / acsinfecdis.1c00585

The authors acknowledge funding from the National Institutes of Health, the Fogarty International Center, and the University of Michigan. Xuefei Juan is the founder of Iaso Therapeutics Inc. A new type of cholera vaccine can provide much longer protection

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