Viral Antigens

HEV is a small, icosahedral, non-enveloped virus with a diameter of approximately 27 to 34 nm . The virus’s genome contains three partially overlapping open reading frames (ORFs): ORF1 encodes nonstructural proteins involved in viral replication, ORF2 encodes the capsid protein, and ORF3 encodes a multifunctional protein believed to be involved in virion release . The virus is shed in the stools of infected persons and enters the human body through the intestine .

HEV primarily targets the liver, causing inflammation and damage. The virus is responsible for acute hepatitis E outbreaks worldwide . HEV infection is usually self-limiting in immunocompetent individuals, but it can lead to chronic hepatitis in immunocompromised patients . The virus plays a role in immune responses and pathogen recognition, with the immune system mounting a response to clear the infection .

HEV enters the human body through the fecal-oral route, primarily via contaminated water . Once inside the body, the virus attaches to cell surface receptors and enters the cells through endocytosis . The viral RNA is then released into the cytoplasm, where it undergoes replication and translation to produce viral proteins . The newly formed virions are assembled and released from the infected cells .

The expression and activity of HEV are regulated at multiple levels. Transcriptional regulation involves the synthesis of viral RNA from the viral genome . Post-translational modifications of viral proteins, such as phosphorylation, play a role in the virus’s life cycle and its interaction with host cells . The immune response also plays a crucial role in controlling HEV infection, with various immune cells and cytokines involved in the antiviral response .

HEV has significant implications in biomedical research, particularly in understanding viral hepatitis and developing diagnostic tools and therapeutic strategies . Diagnostic tools for HEV infection include the detection of HEV RNA and anti-HEV antibodies . Therapeutic strategies for HEV infection focus on supportive care for acute infection and antiviral drugs for chronic infection . A vaccine for HEV has been developed and is licensed in China .

HEV plays a role throughout the life cycle, from development to aging and disease . The virus can cause severe disease in pregnant women, particularly in the third trimester, leading to high mortality rates . In immunocompromised individuals, HEV can lead to chronic hepatitis, which can result in long-term liver damage . The virus’s ability to infect multiple hosts and its zoonotic potential highlight its significance in public health .