A novel microencapsulated peptide vaccine against hepatitis B

A 48 amino acid synthetic peptide (S121/48) representing residues 121-167 o f the major envelope protein of hepatitis B virus (HBsAg) was successfully encapsulated into polylactide co-glycolide microspheres. A single immunizat ion of the microspheres in BALB/c (H-2(d)) mice resulted in the production of high-titre: anti-HBs antibodies (IgG1-type). The response was long lasti ng and was superior to that obtained using the same peptide adjuvanted with Freund's complete adjuvant. A T-cell memory response was detected 10 weeks after a booster immunization (approximately 35 weeks after initial immuniz ation) as measured by in-vitro re-stimulation of splenocytes. This study il lustrates the feasibility of a single dose vaccine for hepatitis B and is, to our knowledge, the first demonstration of a synthetic peptide immunogen inducing anti-native protein antibodies of comparable titre to those obtain ed with conventional vaccines for hepatitis B. The suitability of a synthet ic peptide vaccine for hepatitis B is discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.