HCV-specific immune responses induced by CIGB-230 in combination with IFN-α plus ribavirin

AIM:To analyze hepatitis C virus(HCV)-specific immune responses in chronically infected patients under triple therapy with interferon-α(IFN-α)plus ribavirin and CIGB-230.METHODS:CIGB-230 was administered in different schedules with respect to IFN-αplus ribavirin therapy.Paired serum and peripheral blood mononuclear cells(PBMC)samples from baseline and end of treatment were analyzed.The HCV-specific humoral response was tested by enzyme-linked immunosorbent assay,neutralizing antibodies were evaluated by cell culture HCV neutralization assays,PBMC proliferation was assayed by carboxyfluorescein succinimidyl ester staining and IFN-γsecretion was assessed by enzyme-linked immunospot.Data on virological and histological response and their association with immune variables are also provided.RESULTS:From week 12 to week 48,all groups of patients showed a significant reduction in mean leukocyte counts.Statistically significant reductions in antibody titers were frequent,but only individuals immunized with CIGB-230 as early add-on treatment sustained the core-IgG response,and the neutralizing antibody response was enhanced only in patients receiving CIGB-230.Cell-mediated immune responses also tended to decline,but significant reductions in IFN-γsecretion and total absence of core-specific lymphoproliferation were exclusive of the control group.Only CIGB-230-immunized individuals showed de novo induced lymphoproliferative responses against the structural antigens.Importantly,it was demonstrated that thequality of the CIGB-230-induced immune response depended on the number of doses and timing of administration in relation to the antiviral therapy.Specifically,the administration of 6 doses of CIGB-230 as late addon to therapy increased the neutralizing antibody activity and the de novo core-specific IFN-γsecretion,both of which were associated with the sustained virological response.CONCLUSION:CIGB-230,combined with IFN-α-based therapy,modifies the immune response in chronic patients.The study provides evidence for the design of more effective therapeutic vaccine interventions against HCV.

Cell culture systems for the hepatitis C virus

Since the discovery of HCV in 1989, the lack of a cell culture system has hampered research progress on this important human pathogen. No robust system has been obtained by empiric approaches, and HCV cell culture remained hypothetical until 2005. The construction of functional molecular clones has served as a starting point to reconstitute a consensus infectious cDNA that was able to transcribe infectious HCV RNAs as shown by intrahepatic inoculation in a chimpanzee. Other consen- sus clones have been selected and established in a hu- man hepatoma cell line as replicons, i.e. self-replicating subgenomic or genomic viral RNAs. However, these repli- cons did not support production of infectious virus. Inter- estingly, some full-length replicons could be established without adaptive mutations and one of them was able to replicate at very high levels and to release virus particles that are infectious in cell culture and in vivo. This new cell culture system represents a major breakthrough in the HCV field and should enable a broad range of basic and applied studies to be achieved.