A self-assembling cross-protective antigen against multiple Gram-positive nosocomial pathogens

Abstract

ESKAPE pathogens are responsible for complicated nosocomial infections worldwide and are usually resistant to commonly used antibiotics in clinical settings. Among these bacteria, vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus are the two most important Gram-positive pathogens for which alternative treatments and preventions are urgently needed. We previously designed a multi-presenting antigen, embedding the main epitope displayed by the AdcA protein of E. faecium, that conferred protection against different Gram- positive pathogens both in passive and active immunization models. Here, we developed a new presentation strategy for this epitope, the EH-motif, based on a self-assembling peptide. Self- assembling peptides have been promising in the fields of material sciences, nanoscience, and medicine and have also potential in vaccine development, as they allow multiple presentations of the epitope and provide an ideal size for production and application. We show that this multi- presenting peptide, here Q11-EH, forms stable fibers of nanometric size. We also demonstrate that antibodies raised against Q11-EH mediate the opsonic killing of a wide-spectrum of Gram-positive pathogens, including E. faecium, S. aureus, and E. faecalis. Our data indicate that multiple presentation strategies are a potent tool for vaccine antigen improvement and point to Q11-EH as a promising antigen for the development of novel cross-protective vaccines.