# Determination of Multiplicity of Infection - (Apr/01/2008 )

Dear All,
I'm trying to infect PBMCs with some mycobacterial strains at a specified multiplicity of infection (MOI). How can I determine the MOI? Please advise. I have no experience with kind of work. Your advise and comments will be highly valued. Jaffek98

-Jaffek98-

QUOTE (Jaffek98 @ Apr 1 2008, 10:52 PM)
Dear All,
I'm trying to infect PBMCs with some mycobacterial strains at a specified multiplicity of infection (MOI). How can I determine the MOI? Please advise. I have no experience with kind of work. Your advise and comments will be highly valued. Jaffek98

Hi You need to know how many cfu/ml correspond to an OD of X (for eexample an OD of 0,66 = 18 millions of CFU/ml). So to determine this you need to realise some dilution of an OD of X and plate those dilutions. After this you can calculate your correspondance.

hope to help

biofred

-Biofred-

QUOTE (Biofred @ Apr 2 2008, 08:02 AM)
QUOTE (Jaffek98 @ Apr 1 2008, 10:52 PM)
Dear All,
I'm trying to infect PBMCs with some mycobacterial strains at a specified multiplicity of infection (MOI). How can I determine the MOI? Please advise. I have no experience with kind of work. Your advise and comments will be highly valued. Jaffek98

Hi You need to know how many cfu/ml correspond to an OD of X (for eexample an OD of 0,66 = 18 millions of CFU/ml). So to determine this you need to realise some dilution of an OD of X and plate those dilutions. After this you can calculate your correspondance.

hope to help

biofred

Hi!
Thanks for your valuable advice. I'll try out what you have suggested.

Jaffek98

-Jaffek98-

just make several dilutions to determine which one gives you sligthly less than 100 % infection

example 1/20 : 100% of infected cells (the MOI is more than 1:1)
1/40 : 100%of infected cells (the MOI is more than 1:1)
1/80 : 100%of infected cells (the MOI is more than 1:1)
1/160 : 96% of infected cells (The MOI is close to 1:1)

-Missele-

QUOTE (Missele @ Apr 2 2008, 04:48 AM)
just make several dilutions to determine which one gives you sligthly less than 100 % infection

example 1/20 : 100% of infected cells (the MOI is more than 1:1)
1/40 : 100%of infected cells (the MOI is more than 1:1)
1/80 : 100%of infected cells (the MOI is more than 1:1)
1/160 : 96% of infected cells (The MOI is close to 1:1)

I apologize but I don't get it. I want to know how much MOI to use on my cells when I want to infect them with virus. I want to do a plaque assay to determine pfu of my virus as well. which can give me the number of active viruses in my stock virus.

-Aidin-

Have a look in this paper. They explain it in details.

-Missele-