Background— Increasing evidence supports the involvement of inflammation and immunity in atherogenesis as well as the role of autoimmunity to heat shock proteins (HSPs) in the progression of atherosclerosis. Mucosal administration of autoantigens decreases organ-specific inflammation and disease in several models of autoimmunity (diabetes, arthritis, and encephalomyelitis) and is also being tested in human clinical trials.

Methods and Results— We examined the effect of nasal or oral administration of mycobacterial HSP-65 on atherosclerotic lesion formation in mice lacking the receptor for LDL that were maintained on a high-cholesterol diet. Animals were nasally or orally treated for 1 week with HSP-65, and a high-cholesterol diet was started after the last treatment. The mice were mucosally treated once a week for 8 or 12 weeks, at which time pathological analysis was performed. We found a significant decrease in the size of atherosclerotic plaques, a reduction in macrophage-positive area in the aortic arch, increased interleukin-10 expression, and a reduced number of T cells in nasally treated animals compared with control animals. A similar trend was observed in orally treated mice, but it was not significant.

Conclusions— Our results demonstrate that nasal vaccination with HSP reduces the inflammatory process associated with atherosclerosis and provides a new immunologic approach for the treatment of atherosclerosis.