Provided herein are insoluble particles that include polypeptides. The polypeptides may have immunogenicity that is greater than the immunogenicity of the same polypeptides when they are not present in the particle. The polypeptides may be soluble before incorporation into the particles and insoluble after incorporation into the particles. The particles may include lipopolysaccharide, wherein the lipopolysaccharide is insoluble. The particles may include a carrier. In one embodiment, a carrier is present at no greater than 0.001 mg carrier/mg particles. In one embodiment, a carrier is present at a ratio of carrier to polypeptide (weight:weight) of no greater than 0.05:1. In one embodiment, a carrier is not detectable in the particles.
