Multiplicity of Infection determination - (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

The MOI is just the ratio of mycobacteria to PBMCs. So you should know how many cells of each type you have and use the MOI to determine how many to mix to get your specified MOI. MOI=

number of mycobacterial cells
number of PMBCs

If this ratio is lower than 1, it means that you should add more PBMCs than mycobacteria and vice versa if it's more than 1. You should determine the number of PBMCs by counting a respective dilution on a hemocytometer and the number of mycobacteria (this I am not sure) by measuring their OD600 (I do this for E.coli) and calculating from that.