Influence of bacterial lactic acid on mucosal immune responses after oral vaccination
Category: Research Poster
Author(s): Sophie Kiehl, Paris Kiehl
Presenter(s): Sophie Kiehl
Mentors(s): McKenzie Fletcher, Allison Vilander, Gregg Dean
Lactic acid bacteria (LAB) colonize the gastrointestinal tract and generally confer immune benefits to their host. Because of this, they are emerging as viable vaccine vectors, particularly against mucosal pathogens. LAB secrete high quantities of lactate as a byproduct of their metabolism, and lactate has been increasingly recognized as an immunomodulator, often in an anti-inflammatory capacity. We are studying how lactate metabolism of LAB affects vaccine efficacy using the bacterial platform Lactobacillus acidophilus. Using Mirasol® Pathogen Reduction Technology system, we inactivated a recombinant L. acidophilus expressing the model antigen ovalbumin. We first verified that inactivation inhibited bacterial growth and reduced lactate metabolism while preserving antigen expression. We then administered the live and inactivated vaccines orally to BALB/c mice and measured lactate concentrations in harvested immune inductive sites (Peyer’s patches and ileal lumen contents) using gas chromatography mass spectrometry. We plan to use lactate concentration data to inform optimization of LAB vaccines, especially for mucosal pathogens such as rotavirus for which current vaccines have limited efficacy.