[CpG oligodeoxynucleotide enhances humoral and cellular immune responses against HBsAg in mice].

OBJECTIVE: To induce stronger humoral and cell mediated immune response against HBsAg and seek more effective methods to treat hepatitis B virus infection. METHODS: 21-mer phosphorothioate oligodeoxynucleotide (ODN) and its control ODN were synthesized and used as an adjuvant of HBsAg and commercial hepatitis B vaccine to enhance their immune responses against HBsAg. Four groups of 33 mice received 2 doses of the mixtures (1.67 microg HBsAg: 16.5 microg CpG ODN) at an interval of 15 days. Group A: HBsAg only, 7 mice; group B: HBsAg + CpG ODN, 10 mice; group C: commercial hepatitis B vaccine, 6 mice; group D: commercial hepatitis B vaccine + CpG ODN, 10 mice. Serum anti-HBs levels and cytotoxic T lymphocyte response (CTL) of splenocytes were assayed 15 days after the last vaccination. RESULTS: The mean absorbent values of blood anti-HBs in the 4 groups were 0.109, 0.435, 0.422 and 0.575, respectively. The rates of CTL response were 8.5%, 37.0%, 1.5%, and 28.0%, respectively. CONCLUSIONS: (1) CpG ODN markedly improves humoral (anti-HBs) and cellular immune response (CTL) induced by HBsAg immunization. (2) There is a synergistic interaction between aluminum and CpG ODN in enhancing the humoral and cellular immune responses against HBsAg. Therefore, CpG ODN might be used to treat chronic hepatitis B virus infection after its safety and effectiveness have been confirmed.