Researchers at the ACS Infectious Diseases have discovered a new Cholera vaccine that can last much longer. This research was conducted by Peng Xu, Edward Ryan, Xuefei Huang and colleagues.
The current standard treatment for Cholera, a bacterial disease caused by the highly contagious V. cholerae only lasts for 2 to 5 years. It is not very active in treatment of young children.
It is made of weakened or killed V. cholerae administered orally. But it has short duration of action in young children. It works by causing the immune system to produce antibodies against the O-specific polysaccharide (OSP) on the surface of V. cholerae. However, this polysaccharide cannot produce a strong, long-lasting immune response when in isolation.
In the new proposed treatment, the researchers developed a very effective method to link multiple copies of O-specific polysaccharide (OSP) to Qβ, a virus-like particle that infects bacteria. This will lead to increased immunity.
Antibody from the blood of recovering cholera patients recognized the modified virus-like particle. But this effect was not observed in patients with typhoid or other bacterial diseases.
The research team tested further by immunizing mice with Qβ-OSP. They observed that three doses led to a strong antibody response that lasted 265 days after the initial dose. The immunized mice antibody recognized the OSP from the V. cholerae.
On mixing the serum antibodies from the mice with other immune system proteins that kill bacteria and with live V. cholerae, they observed that antibodies from two out of the five mice resulted in more bacterial death than those from mice immunized with Qβ alone. The Qβ could mimic natural bacteria by presenting multiple copies of OSP on its surface.
Cholera has a death rate of close to 50% of infected people if not treated immediately. In endemic regions, millions of cases are reported, with almost 143 000 deaths yearly.