Pseudotyping is the process of producing viruses or viral vector

Viral vector

Viral vectors are a tool commonly used by molecular biologists to deliver genetic material into cells. This process can be performed inside a living organism or in cell culture . Viruses have evolved specialized molecular mechanisms to efficiently transport their genomes inside the cells they infect...

s in combination with foreign viral envelope proteins

Viral envelope

Many viruses have viral envelopes covering their protein capsids. The envelopes typically are derived from portions of the host cell membranes , but include some viral glycoproteins. Functionally, viral envelopes are used to help viruses enter host cells...

. The result is a pseudotyped virus

Pseudotyped virus

A pseudotyped virus is an enveloped virus particle assembled with a foreign viral glycoprotein. The process of producing such particles is termed pseudotyping....

 particle.. With this method, the foreign viral envelope proteins can be used to alter host tropism

Host tropism

Host tropism is the name given a process of tropism that determines which cells can become infected by a given pathogen. Various factors determine the ability of a pathogen to infect a particular cell. Viruses, for example, must bind to specific cell surface receptors to enter a cell...

 or an increased/decreased stability of the virus particles. Pseudotyped particles do not carry the genetic material to produce additional viral envelope proteins, so the phenotypic changes can not be passed on to progeny viral particles.

For example, pseudotyping allows to specify the character of the envelope proteins. An often used protein is the glycoprotein G of the Vesicular stomatitis virus

Vesicular stomatitis virus

Vesicular stomatitis Indiana virus is a virus in the family Rhabdoviridae; the well-known Rabies virus belongs to the same family. VSIV can infect insects, cattle, horses, pigs and humans. It has particular importance to farmers in certain regions of the world where it can infect cattle...

 (VSV), short VSV-G. These envelope proteins transduce

Transduction

Transduction is a mechanism whereby genetic material may be transferred from the genes of a bacterium to another bacterium. This may include the actual covalent-bonding of new genetic markers...

 to all cell types

Cell type

A cell type is a distinct morphological or functional form of cell. When a cell switches state from one cell type to another, it undergoes cellular differentiation. A list of distinct cell types in the adult human body may include several hundred distinct types.-References:...

.