Multiplicity of infection

With multiplicity of infection (Engl. Multiplicity of infection , short MOI ) is in the virology the numerical ratio of infectious agents ( virus particles or phage ), to give their target cells. If cells in a cell culture are infected with virus particles, the MOI of this culture can be calculated by dividing the number of viruses by the number of cells. With an MOI of 1, exactly as many virus particles are used as there are cells in the culture. The probability with which a particular cell is actually infected is subject to the statisticalPoisson distribution . The MOI is used in research in transduction , in which genes are introduced into bacteria or cells using viruses, which incorporate these genes into their genome and subsequently produce the encoded proteins.

${\displaystyle P(n)={\frac {m^{n}\cdot e^{-m}}{n!}}}$

${\displaystyle m}$is the MOI, the number of particles that infect the infection target, and is the probability that an infection target (a cell) will be infected by particles. ${\displaystyle n}$ ${\displaystyle P(n)}$ ${\displaystyle n}$

With an MOI of 1 (1 virus particle per cell), the likelihood that a cell will not be infected is, the likelihood that it will be infected by a single virus particle , two particles , three , and so on. From this, the average percentage of cells that are infected at a certain MOI can be calculated by . ${\displaystyle P(0)=36{,}79\,\%}$ ${\displaystyle P(1)=36{,}79\,\%}$ ${\displaystyle P(2)=18{,}39\,\%}$ ${\displaystyle P(3)=6{,}13\,\%}$ ${\displaystyle P(n>0)=1-P(0)}$

The average number of cells infected by at a given MOI can be calculated by: ${\displaystyle m}$

${\displaystyle P(n>0)=1-P(n=0)=1-{\frac {m^{0}\cdot e^{-m}}{0!}}=1-e^{-m}}$

If bacteria or cells are infected with viruses in the laboratory, the following formula is used:

${\displaystyle MOI={\frac {{\text{Volumen}}({\text{Virus}})\cdot {\text{Konzentration}}({\text{Virus}})}{{\text{Volumen}}({\text{Zellkultur}})\cdot {\text{Konzentration}}({\text{Zellkultur}})}}={\frac {Vv\cdot Cv}{Vz\cdot Cz}}}$

literature

• SJ Flint, LW Enquist, VR Racaniello (Eds.): Principles of Virology. 2nd Edition. ASM Press 2003, ISBN 1-55581-259-7
• D. O'Reilly, L. Miller, V. Luckow: Baculovirus Expressing Vectors: A laboratory manual. Oxford University Press 1994, ISBN 0-19-509131-0

Web links

• http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/phage/moi.html