Enzymatic attachment of antigens to probe immune modulation by skin commensals

The skin colonist Staphylococcus epidermidis induces potent T and B cell responses, which can be redirected against antigens of interest by genetic engineering. However, since many taxa in the microbiome are genetically intractable, the utility of this method is limited. Here, we use recombinant sortase to conjugate antigens to the surface of a wide range of Gram-positive bacterial species, and we show that this non-genetic method can be used to generate protective immunity in vivo.