Keio University Human Biology-Microbiome-Quantum Research Center (WPI-Bio2Q) held a seminar as follows.

Date：17:00 -18:00, October 1, 2026

Venue：1F Lounge, Center for Integrated Medical Research, Shinanomachi Campus, Keio University

Speaker：Djenet Bousbaine, PhD
Postdoctoral scholar
Department of Bioengineering
Stanford University, US

Title：Engineering Skin Bacteria for Needle-Free Topical Vaccination

Abstract：
The ubiquitous skin colonist Staphylococcus epidermidis elicits a CD8+ T cell response pre-emptively, in the absence of infection, but the scope and purpose of this program remain unclear. Here, we show that this colonist also induces a potent, durable, and specific antibody response. Colonizing mice with S. epidermidis engineered to display tetanus toxin fragment C elicits neutralizing antibodies that protect against lethal challenge. A related strain expressing a SpyCatcher moiety can be conjugated to recombinant immunogens, and the resulting commensal elicits long-lasting, high antibody titers, including robust nasal IgA. An enzymatic approach to display immunogens on gram-positive bacteria extends this strategy to genetically intractable commensals: Cutibacterium acnes labeled with immunogens elicits strong T and B cell responses. Thus, immunity to common skin colonists involves a coordinated T and B cell response, which can be redirected against pathogens as a novel form of topical vaccination.