Codelivery of Antigens and Adjuvant in Polymeric Nanoparticles Coated With Native Parasite Membranes Induces Protective Mucosal Immunity Against Giardia lamblia.

The protozoan pathogen Giardia lamblia is an important worldwide cause of diarrheal disease and malabsorption. Infection is managed with antimicrobials, although drug resistance and treatment failures are a clinical challenge. Prior infection provides significant protection, yet a human vaccine has not been realized. Individual antigens can elicit partial protection in experimental models, but protection is weaker than after prior infection. Here, we developed a multivalent nanovaccine by coating membranes derived from the parasite onto uniform and stable polymeric nanoparticles loaded with a mucosal adjuvant. Intranasal immunization with the nanovaccine induced adaptive immunity and effectively protected mice from G. lamblia infection.