Inducing Vaccine-like Immune Response Against Bacterium

Vaccine-like immune responses have been produced to a dangerous bacterium by colonizing 26 healthy volunteers with a related, but harmless, commensal bacterial species.

Neisseria lactamica, the bacterium that usually resides in the upper airways of children, could serve as vehicles for immunization, by delivering molecules from more dangerous bacteria to the respiratory system.

This infection study showed the strategy was safe, as no side effects were reported and the volunteers didn't transmit the commensal bacteria to bedroom-sharers over the 90-day study.

‘New delivery system can be used for manipulating the respiratory microbiome or inducing immune tolerance to allergens’
Read More..

Commensal bacteria has been difficult to genetically engineer N. lactamica to deliver bacterial antigens.

But, Jay Laver and colleagues engineered N. lactamica to express Neisseria Adhesin A as a vaccine antigen from Neisseria meningitidis, which can cause meningitis.

Research team inoculated 26 adult volunteers with the engineered N. lactamica, which persisted in 86% of the subjects for 90 days. The colonization produced immune responses against Neisseria Adhesin A from both plasma cells and memory B cells within 28 days, and the B cells persisted for at least 90 days after colonization.

There were no side effects in the volunteers, none of them transmitted the N. lactamica to any contacts who shared the same bed, and the bacteria could be eradicated after 90 days with antibiotics.

This delivery system can be used for manipulating the respiratory microbiome or inducing immune tolerance to allergens.

Source-Medindia