Hepatitis E: How the virus outwits the immune system
The HHepatitis-E-Virus (HEV) is distributed worldwide. In this country, the pathogen is repeatedly detected in pork products. So far there is no effective drug against it. Researchers are now reporting how the virus immune system austrickst.
Malfunctioning virus particles could be a ruse to distract the immune system from fighting infectious hepatitis E virus, according to a new study. The study results of the team from the Department of Molecular and Medical Virology at the Ruhr University Bochum (RUB) led by Dr. Tony Meister, Dr. Daniel Todt and Prof. Dr. Eike Steinmann were in the journal “PNAS” released.
Different mutations analyzed
Like it in one Message the RUB is called, more than three million people become infected with the hepatitis E virus every year. So far there is no specifically effective drug.
What factors for the virus in the course of his propagation cycle are important and how it manages to maintain the infection has now been investigated by an international research team.
The scientists analyzed various mutations of the virus and found changeswhich may allow the virus to outwit the immune system.
Important defense mechanism against viral infections
An important defense mechanism against viral infections in our body are special proteins antibody. These usually bind specifically to surface proteins of the virus in order to render the pathogen harmless.
But viruses have strategies evolved to evade this identification. During infection with the hepatitis E virus, random mutations often result in virus variants that can coexist within an infected person.
The antiviral agent Ribavirinwhich many chronically infected people receive, can even further increase the formation of such viral variants.
The researchers now looked at eight such Virus variants from samples of chronically infected patients treated with ribavirin. They wanted to know: do the genetic changes have advantages or disadvantages for the virus? For example, do they have an influence on the ability to reproduce or the infectivity?
Differences were found in one mutation
“While seven of the mutations examined behaved exactly like the wild type, we found one mutant differences Can be detected”, explains Toni Meister. This mutation affects the capsid protein, which is essential for packaging the virus particles.
“The viruses with this mutation are assembled incorrectly, are probably smaller than that Wildtypvirusand the capsid protein does not accumulate in the cell”, says Daniel Todt. These particles are not infectious, but are correctly recognized and bound by antibodies of the immune system.
“This could be an advantage for the virus if these defective viruses practically intercept the antibodies so that there are not enough left for correctly composed, infectious ones virus particles“says Eike Steinmann.
Around 70,000 deaths annually
According to the experts, the hepatitis E virus (HEV) is the main cause Virushepatitiden. Around 70,000 people die from this disease every year.
Normally, acute infections in patients heal with intact immune system by itself.
In people with a reduced or suppressed immune system, such as organ transplant recipients or those infected with HIV, HEV can become chronic. Also for pregnant women HEV is particularly threatening. (ad)
Author and source information
This text corresponds to the specifications of medical specialist literature, medical guidelines and current studies and has been checked by medical professionals.
Sources:
- Ruhr-Universität Bochum: How hepatitis E outsmarts the immune system, (accessed: August 21, 2022), Ruhr-University Bochum
- Toni Luise Meister et al.: A ribavirin-induced ORF2 single-nucleotide variant produces defective hepatitis E virus particles with immune decoy function; in: PNAS, (veröffentlicht: 15.08.2022), PNAS
Important NOTE:
This article contains general advice only and should not be used for self-diagnosis or treatment. He can not substitute a visit at the doctor.