In vivo infectivity of liver extracts after resolution of hepadnaviral infection following therapy associating DNA vaccine and cytokine genes

Abstract

SUMMARY. DNA-based vaccination appears of promise for chronic hepatitis B immunotherapy, although there is an urgent need to increase its efficacy. In this preclinical study, we evaluated the therapeutic benefit of cytokine (IL-2, IFN-c) genes co-delivery with DNA vaccine targeting hepadnaviral proteins in the chronic duck hepatitis B virus (DHBV) infection model. Then, we investigated the persistence of replication-competent virus in the livers of apparently resolved animals. DHBV carriers received four injections of plasmids encoding DHBV envelope and core alone or co-delivered with duck IL-2 (DuIL-2) or duck IFN-c (DuIFN-c) plasmids. After long-term (8 months) follow-up, viral covalently closed circular (ccc) DNA was analysed in duck necropsy liver samples. Liver homogenates were also tested for in vivo infectivity in neonatal ducklings. Codelivery of DuIFN-c resulted in significantly lower mean viremia starting from week 21. Viral cccDNA was undetectable by conventional methods in the livers of 25% and 57% of animals co-immunized with DuIL-2 and DuIFN-c, respectively. Interestingly, inoculation of liver homogenates from 7 such apparently resolved animals, exhibiting cccDNA undetectable in Southern blotting and DHBV expression undetectable or restricted to few hepatocytes, revealed that three liver homogenates transmitted hightitre viremia (3-5910 10 vge/mL) to naïve animals. In conclusion, our results indicate that IFN-c gene co-delivery considerably enhances immunotherapeutic efficacy of DNA vaccine targeting hepadnaviral proteins. Importantly, we also showed that livers exhibiting only minute amounts of hepadnaviral cccDNA could induce extremely high-titre infection, highlighting the caution that should be taken in occult hepatitis B patients to prevent HBV transmission in liver transplantation context.

3D microfluidic liver cultures as a physiological preclinical tool for hepatitis B virus infection

“…Even though the initial infection might have been in PHH, the changing phenotype of cells during culture makes interpretation of results difficult. In vivo however, HBV can be transmitted by low pathogen numbers and in the absence of immunomodulation 12 , 13 . This raises the question as to whether a more natural host cell environment including a physiological liver architecture resembling liver sinusoids would impact the susceptibility to infection of PHH with HBV.…”

N-Linked Glycosylation at an Appropriate Position in the Pre-S2 Domain Is Critical for Cellular and Humoral Immunity against Middle HBV Surface Antigen

“…Following the discovery of DNA vaccine technology approximately 20 years ago, significant progress has been made in optimizing their function (Wu et al 2011;Gao et al 2013;Obeng-Adjei et al 2013;Saade et al 2013;Endmann et al 2014;Yoon et al 2015). Post-translational modification of newly synthesized antigens has proven important in determining the level and type of immune response.…”

Immune-modulators to combat hepatitis B virus infection: From IFN-α to novel investigational immunotherapeutic strategies

“…They can be produced by stimulation with PRR agonist, and TLR8 agonist has been shown to be very potent in this respect in the liver 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 17 (Jo et al, 2014). Recombinant forms of these cytokines have not yet been widely used, but several trials performed in animal model or in human, and aiming at investigating DNA vaccination as therapeutic approach have used co-injection of vectors encoding these chemokines, and shown that they indeed improved immune responses (Brass et al, 2015;Chow et al, 1998;Saade et al, 2013;Yang et al, 2012).…”