Immunogenicity of recombinant HBsAg containing PreS epitopes combined with recombinant HBcAg

Abstract

Objective To study humoral and cellular mediated immune response (CMI) to recombinant HBsAg containing PreS epitopes (SS1S2) combined with recombinant HBcAg (C) in BALB/c mice.Methods Female BALB/c mice were divided into 5 groups by a simple random method and intraperitoneally immunized with SS1S2,SS1S2+C,SS1S2+Al(OH)3 (A l) and SS1S2 + C + Al,respectively,at days 0 and 21.PBS was used as control.Blood and spleen were taken 1 week after primary and boost injections.Serum titers of anti-HBs,anti-PreS1,anti-PreS2 and anti-HBc were detected by ELISA.Spleen-lymphocytes were isolated and frequency of IFN-γ-secreting T cells was measured by enzyme-linked immunospot assay.The results were analyzed by t-test.Results High levels of anti-HBc,anti-HBs,antiPreS1 and anti-PreS2 were induced in both groups immunized with HBcAg.One week after primary immunization,the seroconversion ratios of anti-HBs in SS1S2 + C (1/5) and SS1S2 + C + Al (4/5) groups were higher than those in SS1S2 (0/5) and SS1S2 +Al (3/5) groups,respectively.The seroconvesion ratio of antiPreS1 in SS1S2 + C group (3/5) was higher than that in SS1S2 group (0/5).The production of anti-PreS2 was not affected by combination with HBcAg.After boost,the levels of anti-HBs,anti-PreS1 and anti-PreS2 in groups with HBcAg were higher than those in groups without HBcAg.All vaccine groups generated CMI response.One week after primary immunization,the frequency of IFN-γ-secreting T cells in SS1S2 + C and SS1S2 +Al +C groups was higher than those in SS1S2 and S1S2 + Al groups (t =2.926,2.974,P ＜0.05).After boost,the T cell frequency in SS1S2 + C group was significantly higher than that in SS1S2 group (t =4.604,P =0.010).Conclusions SS1S2 combined with HBcAg has strong immunogenicity in mice and HBcAg could enhance humoral and CMI responses to SS1S2. Key words: Hepatitis B surface antigens; Hepatitis B core antigens; Immunogenecity; Immunity,humoral ; Immunity, cellular