Abstract: Disclosed herein are bacteria-based HIV MPER vaccine candidates, as well as bacteria-based candidates for other viruses and for bacteria. The HIV vaccine candidates express MPER-derived antigens on their surfaces using Gram autotransporters. The surface-expressed MPER antigens bind several different MPER-directed anti-HIV Broadly Neutralizing Monoclonal Antibodies. When the bacteria expressing the MPER-derived antigens on their surfaces are used to immunize mice they elicit the production of sera and vaginal wash material that bind the bacteria expressing the MPER antigens. At least one of the bacteria expressing MPER-derived antigens on their surfaces elicits the production of sera with anti-HIV neutralizing activity.