There are lots of commercially available kits claiming they can but I want a "real-lab" example of a positive response to the infection followed by treatment and then re-check numerous passages after to confirm it was successful.
Once your cell cultures become contaminated with mycoplasma, you might as well trash the cells and start over. There is no way to remove that contaminant from your cell culture. There may be commercial kits claiming that they can "remove" this from the culture, but I am a complete skeptic. If you want to confirm that your contamination is actually mycoplasma, there are commercial services who can do that.
The cell lines in question have certain proteins stably knocked down which took several months to achieve. Therefore I don't want to throw them away lightly. I agree with your skepticism and have posted this question more in hope!
It is reasonable to check for mycoplasma regularly and to avoid it. I remember some 20 years ago that a CD44/metastasis lab had infections with the cell lines. If I remember correctly some of my colleagues at that time some tried everything to get some mycoplasma-free cells to reproduce some metastasis-experiments. I am not sure that this ever worked out. It seemed that some of the cell-lines were more and some less infected, which led to the assumption the metastasis-effect was due to the mycoplasma-strain and not the subtypes of CD44...
I think you may check some of your earliest aliquots/stock samples for mycoplasma and use those - I think this is what Anne recommended already, but you may have done that. Otherwise wait 1-2 weeks to get more feedback on what may really work without harming the cells.
I once had an interview at Harvard (in the 1990s) and the young assistant professor who offered me immediately a position told me the standards there are expensive in the first view, since every cell line has to be tested for mycoplasma. I think this is a good standard.
I disagree with above.. We had global mycoplasma contamination in most of our freeze-downs and cleaned them all up, using both a Mycoplasma kit (Lookout mycoplasma elimination kit -Sigma), and separately: Ciprofloxacin (http://cellgro.com/media/upload/file/productinfosheets/new/Ciprofloxacin%20Hydrochloride.pdf)
This worked great for us. Like antibiotics, make sure you treat for the recommended time (minimum 3 weeks). Since then, we have maintained our cells without cipro, or any other maintenance reagent, and they have stayed clean.
EDIT: Also...quick test for mycoplasma...DAPI stain. If you get blue in anything but the nucleus (fibrous stain in the cytoplasm) or sometimes on the coverslip, not in a cell, that is the DNA from the mycoplasma staining positive. It can be used to EASILY monitor your cultures periodically. NOTE...even if a treated line looks clean before 3 weeks splitting to low confluence repeatedly DO NOT STOP TREATMENT. 1 mycoplasma surviving will drive the culture dirty again over time.
Just to add.. We had a function failure of our contaminated mammary epithelial line, they were impossible to maintain, and would not differentiate. After treatment the cultures expanded easily as expected, and full function differentiation with lactogenic hormones was achieved. (just adding some support for my comment above)
It looks like there is one working example described by Stephen.
David, since you invested so much time in your cell line you may consider starting all options within short time: 1) use at least one (or more) anti-mycoplasma treatments AND 2) restart the original experiment which resulted in getting you the cells you designed. Imagine you will know only after weeks if 1) really worked... The other thing is that any treatment in cell culture may have some influence to your cells - epigenetic changes accumulate which lets some researchers doubt more and more cell culture experiments...
i agree with robert about the potential for changes to your cells. Hence, why we used a commercial product and a antibiotic in parallel. It is an important consideration to make.
Thank you both Robert and Stephen for your input, some great advice there. I think your dual approach is the safest way to go forward and I will have to set up a second culturing location (flow hood and incubator) to treat the infected cells while starting again from scratch in clean cells in a sterile environment. It's a bit of a set back but this plan should minimise experimental downtime so thanks!
Mycoplasmas represent ideal cell culture nuisances, because it can remain undetected. I prefer that cell lines laboratories depend effective prevention program and control all preceding factors that contribute the mycoplamal infections.
Update - I treated the cells for 3 weeks with 5ug/ml ciprofloxacin and they have come back negative following the MycoAlert kit from Lonza and nuclear staining. As a precaution we are now increasing the frequency of our routine checks. Thanks everyone for your input!