Hepatitis B Virus

Chiaho Shih1, Ching-Chun Yang2, Gansukh Choijilsuren2

  • 1Institute of Biomedical Sciences (IBMS), Academia Sinica, Taipei, Taiwan; Taiwan International Graduate Program (TIGP) in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan; Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan.

This infographic about hepatitis B virus explores its replication cycle, natural history of infection and pathogenesis, and how this can be controlled and treated. Hepatitis B virus (HBV) is a common worldwide blood-borne pathogen. Chronic hepatitis B can progress to an inactive carrier state, and then, in some patients, give rise to cirrhosis and cancer of the liver, leading to death. An HBV surface-antigen vaccine is effective, but treatments are currently not curative. HBV replicates via reverse transcription. Its covalently closed circular (ccc) DNA in the nucleus encodes a pregenomic RNA (pgRNA), which can be encapsidated by HBV polymerase. Reverse transcription occurs in the capsids by using the pgRNA as a template for the synthesis of single-stranded linear and then partially double-stranded relaxed circular (rc) DNA. Capsids containing a mature rc DNA genome target to the nucleus for ccc DNA synthesis. Persistent HBV infection is caused mainly by ccc DNA and immune tolerance to HBV antigens in the liver. Unlike acute infection, chronic carriers contain only a low level of HBV core-antigen-specific T cell activity, contributing to the lack of viral clearance.

Related Concept Videos

What are Viruses?00:50

What are Viruses?

Overview
128.4K
Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment01:08

Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment

Hepatic impairment, characterized by decreased liver function, does not uniformly mandate adjustments in drug dosage. Whether dosage modifications are necessary depends on various factors related to the drug's metabolism and elimination pathways. If a drug is primarily excreted via the kidneys and bypasses significant hepatic processing, if it undergoes minimal metabolic transformation in the liver, or if it is volatile and primarily expelled through the lungs, dose adjustments may not be...
281
Hepatic Portal System01:21

Hepatic Portal System

The hepatic portal system, a critical part of our circulatory framework, transports nutrient-laden, deoxygenated blood from the gastrointestinal tract and spleen to the liver. This ingenious system plays an indispensable role in maintaining our body's metabolic equilibrium.
At its core, the hepatic portal vein is the result of a confluence of the superior and inferior mesenteric veins along with the splenic vein. Each of these veins has a unique role. The superior mesenteric vein is...
6.3K
Effect of Hepatic Disease on Pharmacokinetics: Drug Dosing and Hepatic Blood Flow01:26

Effect of Hepatic Disease on Pharmacokinetics: Drug Dosing and Hepatic Blood Flow

Chronic liver disease significantly impacts drug metabolism due to alterations in hepatic blood flow and enzyme accessibility. This disruption affects the body's pharmacokinetics—the movement and processing of drugs within the system. Key enzymes crucial for metabolizing medications become less accessible, changing how drugs are processed and utilized. Furthermore, liver disease influences the synthesis of plasma proteins, such as albumin and globulins, which play critical roles in drug...
255
Hepatic Drug Excretion: Influencing Factors01:16

Hepatic Drug Excretion: Influencing Factors

The biliary system of the liver, crucial for bile secretion and drug excretion, comprises intrahepatic bile ducts that merge to form the common hepatic duct. This duct, carrying hepatic bile, combines with the cystic duct, draining the gallbladder and forming the common bile duct, which empties into the duodenum. Bile, produced by hepatic cells lining the bile canaliculi, is composed primarily of water, bile salts, pigments, electrolytes, and lesser amounts of cholesterol and fatty acids. Bile...
609
Hepatic Drug Clearance: Role of Transporters01:14

Hepatic Drug Clearance: Role of Transporters

In the liver and bile canaliculi, influx and efflux transporters modification can influence intrinsic clearance. Transporters play a significant role in moving drugs within liver cells. Elaborate models, such as the Biopharmaceutical Classification System (BCS), are essential to relate transporters to drug disposition. This system categorizes drugs into four classes based on solubility and permeability, providing insights into elimination routes and the effects of transporters following oral...
312