Recombinant polymorphic membrane protein D in combination with a novel, second-generation lipid adjuvant protects against intra-vaginal Chlamydia trachomatis infection in mice

•rPmpD in combination with SLA elicits significant protection against intra-vaginal Ct challenge.•Antibodies induced by immunisation with rPmpD recognise Ct elementary bodies.•SLA is a novel adjuvant class that may be widely used in future preclinical Ct vaccine development.