Hepatitis B Virus


Pathogenesis: Shortly after the virus enters a new host, it’s initial response is to infect liver cells, called hepatocytes. The virus' main target is the liver because the virus possesses surface antigens specific for receptors found on liver cells only. The binding of these viral antigens to hepatocyte receptors induces viral entry by receptor-mediated endocytosis and uncoats in the cytoplasm. Generally, the liver is responsible for purifying blood and processing nutrients. A healthy liver is essential to the functioning of blood, lymph, and bile production. If the liver fails, all other organs in the body will soon start to fail.

Within the cytoplasm, the core particle of the virion translocates its content of viral DNA and DNA polymerase into the hepatocyte nucleus. The DNA is then organized to form a viral mini-chromosome. Once within the cell nucleus, the hepatitis B genome is transcribed into mRNA (messenger RNA), where it is subsequently translated into hepatitis B viral surface proteins, viral core proteins, DNA polymerase, and hepatitis B e-antigen protein. The cell then assembles live copies of the virus. The copies of the virus are released from the liver cell membrane into the bloodstream and from there can infect other liver cells and thus replicate effectively.