To evaluate atheroprotective effects of different doses of cholesteryl ester transfer protein (CETP) vaccine, three doses of Tetanus toxoid-CETP (TT-CETP) peptide including 10, 50 and 100/rabbit, termed FA10, FA50, FA100, respectively, were administered in rabbit model of atherosclerosis.

Animals were vaccinated subcutaneously (S.C.) with 100μl of vaccine in presence of complete Freund’s adjuvant (CFA) for the first administration. Rabbits were boosted 4 times at 3 weeks intervals with the same peptide dose formulated in incomplete Freund’s adjuvant (IFA). Animals were fed with diet supplemented with 2% cholesterol from week 11 to week 19. Anti-TT-CETP specific antibody and CETP activity in sera were determined. Therapeutic response was examined by tracking plasma lipoprotein levels (HDL-C, LDL-C and total cholesterol), and pathologic observation of intima/media thickness at the site of aortic lesions.

All TT-CETP vaccine doses generated strong anti TT-CETP antibody response. CETP activity reduced in rabbits vaccinated with FA100 (P=0.031). FA100 showed significant increase in level of HDL-C rather than control group (P=0.006). However, no significant reduction were found in atherosclerotic lesion when compared to control.

Inhibition of CETP activity and increased HDL-C were found with FA100, but the vaccine failed to prevent aortic lesion development in immunized rabbits when compared to control. Our result supports the hypothesis stated that CETP may not be an attractive therapeutic target for the prevention of cardiovascular disease.