Multiplicity of Infection (MOI): What is it and how do I calculate it?

[@greta7885]

It took me forever to find a resource that laid out both the idea and formula for MOI in such a simple and accessible way. Thank you! P.S. the virus animations are super cute :)

[@abmgood]

Hi Greta, thank you so much for your nice comment. We're glad you found the video helpful and that you like the virus animations! 😀👍

[@supernovaHD0]

This was fantastic, I've been trying to write an assignment that has a heavy focus on MOI, and this has helped so much. Thank you

[@abmgood]

You're very welcome! Glad you found the video helpful ;)

[@asdf5341]

Hi! Your video is slightly inaccurate. The MOI is not based on the number of virus, but the number of infectious particles, often termed transducing unit (TU) or infectious unit (IFU). ie. Not all virus particles are infectious. Thus, for example, viral titers are determined experimentally, not by determining the number of copies of a virus in solution.

[@abmgood]

We agree that MOI is based on the number of infectious particles, thank you for helping to make our video even clearer for other viewers.

[@beldaanita]

thank you so much, gosh this video explains the concept so well

[@mihermione]

THANK YOU SO MUCH THIS IS REALLY A HELP!!

[@abmgood]

No problem! Thanks for watching!

[@immylon4608]

Nice explanation. Is it safe to consider Infection unit in this video is same as PFU(plaque forming units)?

[@ArnavPadhi]

Can u plz tell how to achieve a MOI of 0.001 having a mixture of bacteria and phage

[@luisamacias9203]

omg, I love this video so much, thank uuuu

[@abmgood]

Glad you enjoyed it! Thanks for watching ;)

[@jenniayan6731]

Thank you very much

[@labtechnologistkalulewilbe6674]

Wow grt video

[@shaunjoe7710]

In an invitro drug interaction study, how do you calculate the MOI with respect to a real life infection of that virus?

[@abmgood]

Thank you for your question! MOI is the ratio of the number of virus particles to the number of target cells, calculated by: Product Titer (IU/ml) x Virus Volume (ml) MOI = ____________________________________________ Total Cell Number MOI would not give indications on a real life infection of that virus, and for in vitro drug interactions, you may find the concept of Minimum Inhibitory Concentration (MIC) more relevant to your study. We hope this helps, please let us know if you have any more questions!

[@shaunjoe7710]

@@abmgood Thank you. Great help.

[@abmgood]

@@shaunjoe7710 You're welcome! :)

[@shaunjoe7710]

Great Video.. How do we determine MOI of different viruses? What characters of the virus do we consider while determining the MOI, provided there is a fixed number of cell of an appropriate cell line? Like isnt 0.1 MOI too less to show successful infection?

[@abmgood]

Hi Shaun, the best way to determine MOI of different viruses is to test varying MOIs in a small sized dish containing your cell line of choice, and determine at what MOI will 100% of the cells contain your gene of interest. As for the virus - insert size, promoter type, linker, and fluorescent type are the most common characteristics we look at when determining MOI. For example, a strong promoter, such as CMV, would usually require a lower MOI than, say, and IRES promoter with the same GOI and construct in most cell lines. Your optimal MOI varies depending on the cell line of choice, and the virus of choice. An MOI of 0.1 could work for baculovirus transduction, for example, but will not be effective with AAV transduction. Hope this helps!

[@shaunjoe7710]

@@abmgood Thankss.. great help😌

[@abmgood]

@@shaunjoe7710 You're welcome!

[@ahainine3222]

Nice summary In COVID19 studies Why use veroE6? MOI 0.01 to 0.8 is the good?

[@abmgood]

ACE2 expression is very high in VeroE6 cells and thus, SARS-CoV-2 can be isolated using VeroE6 cells. A recent paper indicates that an engineered cell line, VeroE6/TMPRSS2, is highly susceptible to SARS-CoV-2 infection, indicating its potential utility for isolating and propagating this virus. Regarding the MOI, it will be cell-specific and we highly recommend looking into available publications for MOI used in the same cells. If you would like to discuss further, please contact [e-mail].

[@HO-YTchannel]

Thank You!

[@abmgood]

Thanks for watching! :)

[@HO-YTchannel]

@@abmgood Actually after I read about the topic a bit more I have a question: Say we are using MOI equal 10 that means I have 10:1 (virus : cells) right? Now my question: These 10 units of the virus Are they referring to viral particles in general or to infective viral units? Let me say it in another way the 10 units here are counted by a technique like plaque forming assay therefore the 10 here refers to 10 pfu? Or The 10 here are viral particles counted with some technique like qPCR regardless of whether these viruses are infective or not?

[@abmgood]

@@HO-YTchannel The formula for MOI is calculated as (viral titer x virus volume) / total cell number. Therefore whether these 10 units of viral particles refer to physical or infectious viral particles depend on the titration method used and whether the physical or functional titer is used for MOI calculation. In the example shown in the video (at 1:10), the titer is calculated as infectious units (IU) and therefore refers to infectious viral particles in this case. For more information regarding different lentiviral titration methods and physical Vs. functional titers, please visit: kzbin.info/www/bejne/kKiYaIWwjpV1fLs

[@HO-YTchannel]

@@abmgood Thank you for clarification, your answers are really helping me a lot in understanding the concept!

[@Ramohan86]

Thank you for the great visualisation and conceptualisation of important aspects of gene therapy in this movie but also the other movies posted by ABM. I have two questions: 1) On average, what proportion of 3rd-generation lentivirus particles is infectious? (in other words, relation GC/mL and IU/mL)? 2) How would you go about determining the titer (IU/mL) if you do not have the option to include a marker as transgene and do not want to use GC/mL? Best, Rajiv

[@abmgood]

Hello Rajiv, 1) There is no straightforward way to convert GCmL to IU/mL and vice versa. The number of infecting particles has to be determined experimentally. 2) You may use abm's qPCR Lentivirus Titration (Titer) Kit (LV900). You can find more information about this kit here: www.abmgood.com/qpcr-lentivirus-titration-titer-kit-lv900-vin.html Please contact us at [e-mail] if you have more questions!

[@miltsimii6871]

Moi

[@701i3]

i think its 10ml

[@morrisdonald8795]

#DrObahistoricalherbs🧡