Immunization of Mice by BCG Formulated HCV Core Protein Elicited Higher Th1-Oriented Responses Compared to Pluronic-F127 Copolymer

Background: a supreme vaccine for hepatitis c virus (hcv) infection should elicit strong th1-oriented cellular responses. in the absence of a th1-specific adjuvant, immunizations by protein antigens generally induce th2-type and weak cellular responses. objectives: to evaluate the adjuvant effect of bcg in comparison with nonionic copolymer-pluronic f127 (f127) as a classic adjuvant in the formulation of hcv core protein (hcvcp) as a candidate vaccine for induction of th1 immune responses. materials and methods: expression of n-terminally his-tagged hcvcp (1-122) by pivex2.4a-core vector harboring the corresponding gene under the control of arabinose-inducible (arabad) promoter was achieved in bl21-ai strain of e.coli and purified through application of nitrilotriacetic acid (ni-nta) chromatography. mice were immunized subcutaneously (s.c.) in base of the tail with 100 μl of immunogen (f127+hcvcp or bcg+hcvcp; 5 μghcvcp/mouse/dose) or control formulations (pbs, bcg, f127) at weeks 0, 3, 6. total and subtypes of igg, as well as cellular immune responses (proliferation, in vivo ctl and ifn-γ/il-4 elispot assays against a strong and dominant h2-d restricted, cd8+-epitopic peptide, core 39-48; rrgprlgvra of hcvcp) were compared in each group of immunized animals. results: expression and purification of core protein around the expected size (21 kda) was confirmed by western blotting. the hcvcp + bcg vaccinated mice showed significantly higher lymphocyte proliferation and ifn-γ production but lower levels of cell lysis (45% versus 62% in ctl assay) than the hcvcp+f127 immunized animals. “besides, total anti-core igg and igg1 levels were significantly higher in hcvcp + f127 immunized mice as compared to hcvcp + bcg vaccinated animals, indicating relatively higher efficacy of f127 for the stimulation of humoral and th2-oriented immune responses”. conclusions: results showed that hcvcp + bcg induced a moderate ctl and mixed th1/th2 immune responses with higher levels of cell proliferation and ifn-γ secretion, indicating that bcg may have a better outcome when formulated in hcvcp-based subunit vaccines.