Enhanced Fatty Streak Formation in C57BL/6J Mice by Immunization With Heat Shock Protein-65

Abstract

—Recent data suggest that the immune system is involved in atherogenesis. Thus, interest has been raised as to the possible antigens that could serve as the initiators of the immune reaction. In the current work, we studied the effects of immunization with recombinant heat shock protein-65 (HSP-65) and HSP-65–rich Mycobacterium tuberculosis (MT) on early atherogenesis in C57BL/6J mice fed either a normal chow diet or a high-cholesterol diet (HCD). A rapid, cellular immune response to HSP-65 was evident in mice immunized with HSP-65 or with MT but not in the animals immunized with phosphate-buffered saline (PBS) alone. Early atherosclerosis was significantly enhanced in HCD-fed mice immunized with HSP-65 (n=10; mean aortic lesion size, 45 417±9258 μm2) or MT (n=15; 66 350±6850 μm2) compared with PBS-injected (n=10; 10 028±3599 μm2) or nonimmunized (n=10; 9500±2120 μm2) mice. No fatty streak lesions were observed in mice fed a chow diet regardless of the immunization protocol applied. Immunohistoche...