Knockdown of Virus Antigen Expression Increases Therapeutic Vaccine Efficacy in High-Titer Hepatitis B Virus Carrier Mice.
Animals
B-Lymphocytes
/ immunology
Carrier State
/ immunology
Combined Modality Therapy
/ methods
Disease Models, Animal
Female
Gene Knockdown Techniques
Hepatitis B Surface Antigens
/ genetics
Hepatitis B Vaccines
/ administration & dosage
Hepatitis B virus
/ genetics
Hepatitis B, Chronic
/ diagnosis
Hepatocytes
/ virology
Humans
Immunization, Secondary
Immunogenicity, Vaccine
Male
Mice
RNA, Small Interfering
/ administration & dosage
T-Lymphocytes, Cytotoxic
/ immunology
Virus Replication
/ genetics
Immunization
Immunotherapy
Viral Hepatitis
siRNA
Journal
Gastroenterology
ISSN: 1528-0012
Titre abrégé: Gastroenterology
Pays: United States
ID NLM: 0374630
Informations de publication
Date de publication:
05 2020
05 2020
Historique:
received:
05
06
2019
revised:
28
12
2019
accepted:
20
01
2020
pubmed:
1
2
2020
medline:
21
10
2020
entrez:
1
2
2020
Statut:
ppublish
Résumé
Hepatitis B virus (HBV) infection persists because the virus-specific immune response is dysfunctional. Therapeutic vaccines might be used to end immune tolerance to the virus in patients with chronic infection, but these have not been effective in patients so far. In patients with chronic HBV infection, high levels of virus antigens might prevent induction of HBV-specific immune responses. We investigated whether knocking down expression levels of HBV antigens in liver might increase the efficacy of HBV vaccines in mice. We performed studies with male C57BL/6 mice that persistently replicate HBV (genotype D, serotype ayw)-either from a transgene or after infection with an adeno-associated virus that transferred an overlength HBV genome-and expressed HB surface antigen at levels relevant to patients. Small hairpin or small interfering (si)RNAs against the common 3'-end of all HBV transcripts were used to knock down antigen expression in mouse hepatocytes. siRNAs were chemically stabilized and conjugated to N-acetylgalactosamine to increase liver uptake. Control mice were given either entecavir or non-HBV-specific siRNAs and vaccine components. Eight to 12 weeks later, mice were immunized twice with a mixture of adjuvanted HBV S and core antigen, followed by a modified Vaccinia virus Ankara vector to induce HBV-specific B- and T-cell responses. Serum and liver samples were collected and analyzed for HBV-specific immune responses, liver damage, and viral parameters. In both models of HBV infection, mice that express hepatocyte-specific small hairpin RNAs or that were given subcutaneous injections of siRNAs had reduced levels of HBV antigens, HBV replication, and viremia (1-3 log In mice with high levels of HBV replication, knockdown of HBV antigen expression along with a therapeutic vaccination strategy, but not knockdown alone, increased numbers of effector T cells and eliminated the virus. These findings indicate that high titers of virus antigens reduce the efficacy of therapeutic vaccination. Anti-HBV siRNAs and therapeutic vaccines are each being tested in clinical trials-their combination might cure chronic HBV infection.
Sections du résumé
BACKGROUND & AIMS
Hepatitis B virus (HBV) infection persists because the virus-specific immune response is dysfunctional. Therapeutic vaccines might be used to end immune tolerance to the virus in patients with chronic infection, but these have not been effective in patients so far. In patients with chronic HBV infection, high levels of virus antigens might prevent induction of HBV-specific immune responses. We investigated whether knocking down expression levels of HBV antigens in liver might increase the efficacy of HBV vaccines in mice.
METHODS
We performed studies with male C57BL/6 mice that persistently replicate HBV (genotype D, serotype ayw)-either from a transgene or after infection with an adeno-associated virus that transferred an overlength HBV genome-and expressed HB surface antigen at levels relevant to patients. Small hairpin or small interfering (si)RNAs against the common 3'-end of all HBV transcripts were used to knock down antigen expression in mouse hepatocytes. siRNAs were chemically stabilized and conjugated to N-acetylgalactosamine to increase liver uptake. Control mice were given either entecavir or non-HBV-specific siRNAs and vaccine components. Eight to 12 weeks later, mice were immunized twice with a mixture of adjuvanted HBV S and core antigen, followed by a modified Vaccinia virus Ankara vector to induce HBV-specific B- and T-cell responses. Serum and liver samples were collected and analyzed for HBV-specific immune responses, liver damage, and viral parameters.
RESULTS
In both models of HBV infection, mice that express hepatocyte-specific small hairpin RNAs or that were given subcutaneous injections of siRNAs had reduced levels of HBV antigens, HBV replication, and viremia (1-3 log
CONCLUSIONS
In mice with high levels of HBV replication, knockdown of HBV antigen expression along with a therapeutic vaccination strategy, but not knockdown alone, increased numbers of effector T cells and eliminated the virus. These findings indicate that high titers of virus antigens reduce the efficacy of therapeutic vaccination. Anti-HBV siRNAs and therapeutic vaccines are each being tested in clinical trials-their combination might cure chronic HBV infection.
Identifiants
pubmed: 32001321
pii: S0016-5085(20)30125-6
doi: 10.1053/j.gastro.2020.01.032
pii:
doi:
Substances chimiques
Hepatitis B Surface Antigens
0
Hepatitis B Vaccines
0
RNA, Small Interfering
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
1762-1775.e9Informations de copyright
Copyright © 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.