I intend to design a study which would require Haemeagglutination assay for a growth factor (g.f) and have referred to few website which have mentioned the E.D 50 value for that g.f. but I am unable to find relevant research articles for the same. Kindly help.
Dear Mohammad, the haemagglutination assay used to determine a virus titer or such, so I'm not sure how to use it to determine ED50 which means a half-lethal dose. Anyways, EC50 - half effective concentration can be determined by plotting the assay result as a function of concentration or dilution factor, and then fitting these data to a sigmoid function. There are numerous papers and book s on this procedure. best: Karoly
Dear Karoly Liliom thank you for your response, however the websites that I have referred to have provided "E.D 50" values for the lectin on performing HA.
I think that my question should have been 'how to determine E.D50 for a lectin by performing haemeagglutination assay'.
Mohammed, sorry for misreading the ED50, of course LD50 would be the half-lethal dose, so this is half-effective dose, or half-effective dilution, which is practically the same as the half-effective concentration. Anyways, you probably do a serial dilution and determine some absorbance values (or sg. similar depending on your instrumentation) - let's call it "response". You can plot your response values as a function of the dilution, and by non-linear fitting you may fit a 4-parameter sigmoid function to your data. It may look like this: Response = Rmin + (Rmax-Rmin) * (D^n/(ED50^n + D^n)) where Rmin stands for the starting response value, Rmax for the ending value, "n" is the cooperativity coefficient, and D stands for the dilution factor (but it works just as well with real concentrations if you know it). Practically this is a symmetric function and its midpoint represent the ED50 (or EC50). Hope this helps. Cheers, Karoly
Karoly Liliom, Just wanted to inform you that we've found the methodology for determining the E.D 50 of lectins by haemeagglutination assay.
The image of the haemeagglutination assay is to be quantified using the Image J software and the reading is then used to prepare a graph, which is then used to determine the E.D 50.
Here is the reference if you're interested:
Gasson, R., Roper, J. A., & Slack, R. J. (2024). A Quantitative Human Red Blood Cell Agglutination Assay for Characterisation of Galectin Inhibitors. International Journal of Molecular Sciences, 25(12), 6756.
Thanks and regards.
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