A helper virus is a

virus A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...

that allows an otherwise-deficient coinfecting virus to replicate. These can be naturally occurring as with

Hepatitis D virus Hepatitis D is a type of viral hepatitis caused by the hepatitis delta virus (HDV). HDV is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a satellite (a type of subviral agent) because it can propagate only in ...

, which requires

Hepatitis B virus Hepatitis B virus (HBV) is a partially double-stranded DNA virus, a species of the genus '' Orthohepadnavirus'' and a member of the '' Hepadnaviridae'' family of viruses. This virus causes the disease hepatitis B. Classification Hepatitis B ...

to coinfect cells in order to replicate. Helper viruses are also commonly used to replicate and spread

viral vector A viral vector is a modified virus designed to gene delivery, deliver genetic material into cell (biology), cells. This process can be performed inside an organism or in cell culture. Viral vectors have widespread applications in basic research, ...

s for gene expression and

gene therapy Gene therapy is Health technology, medical technology that aims to produce a therapeutic effect through the manipulation of gene expression or through altering the biological properties of living cells. The first attempt at modifying human DNA ...

References

Virology {{virus-stub

See also

References