Sublingual vaccine with GroEL attenuates atherosclerosis

Autoimmune responses to heat-shock protein 60 (HSP60) contribute to the progression of atherosclerosis, whereas immunization with HSP60 may induce atheroprotective responses. We assessed the capacity of an atheroprotective vaccine that targeted a recombinant HSP60 from Porphyromonas gingivalis (rGroEL) to induce a protective mucosal immune response. Female apolipoprotein E-deficient spontaneously hyperlipidemic (Apoe(shl)) mice received sublingual delivery of rGroEL prior to P. gingivalis 381 injection. The animals were euthanized 16 weeks later. Sublingual immunization with rGroEL induced significant rGroEL-specific serum IgG responses. Antigen-specific cells isolated from spleen produced significantly high levels of IL-10 and IFN-γ after antigen re-stimulation in vitro. Flow cytometric analysis indicated that the frequencies of both IL-10(+) and IFN-γ(+) CD4(+) Foxp3(+) cells increased significantly in submandibular glands (SMG). Furthermore, sublingual immunization with rGroEL significantly reduced atherosclerosis lesion formation in the aortic sinus and decreased serum CRP, MCP-1, and ox-LDL levels. These findings suggest that sublingual immunization with rGroEL is associated with the increase of IFNγ(+) or IL-10(+) Foxp3(+) cells in SMG and a systemic humoral response, which could be an effective strategy for the prevention of naturally occurring or P. gingivalis-accelerated atherosclerosis.