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Modified Injectable Polio Vaccine Shows Enhanced Mucosal Immunity in Rat Study

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Modified Polio Vaccine Shows Promise in Blocking Virus Transmission

MIT researchers have developed a modified injectable polio vaccine that induces a mucosal immune response in the gut, potentially blocking virus transmission while maintaining safety.

Background on Polio Vaccines

Two types of polio vaccines are currently in use. The injectable polio vaccine (IPV) provides protection against illness but does not prevent individuals from shedding the virus, meaning it does not block transmission. The oral polio vaccine (OPV) induces mucosal immunity in the gut, which can reduce or prevent transmission, but carries a rare risk of reverting to a form that can cause polio.

Key Study Details

Methodology

  • The new formulation uses a lipid nanoparticle (LNP) to encapsulate an adjuvant called Am80, a derivative of vitamin A.
  • The LNP system releases Am80 over several days, eliminating the need for multiple daily injections.
  • The nanoparticles accumulate in lymph nodes and stimulate B and T cells to produce homing signals that direct immune cells to the gastrointestinal tract.

Results

  • In rats, the modified vaccine produced a 20-fold increase in immunoglobulin A (IgA) antibodies, which are associated with mucosal immunity, compared to IPV alone.
  • The vaccine also generated immunoglobulin G (IgG) antibodies, which are associated with systemic immunity.

Researcher Statements

"Individuals vaccinated with standard IPV do not become ill but may still shed the virus."
— Ana Jaklenec, principal investigator at MIT's Koch Institute

Jaklenec noted that inducing mucosal immunity could reduce or eliminate viral shedding.

"The Am80 adjuvant enables a mucosal immune response that is normally only achievable with the oral polio vaccine, while maintaining the safety profile of the injectable vaccine."
— Behnaz Eshaghi, lead author of the study

Future Plans

The researchers plan to test the vaccine in larger animal models. They are also developing a single injection that combines the vaccine and adjuvant. The team noted that the adjuvant platform could potentially be adapted for vaccines against other pathogens that infect mucosal surfaces, such as the gastrointestinal tract, respiratory tract, and reproductive tract.

Funding

The research was funded by the Bill & Melinda Gates Foundation.