Guest Wendy Posted November 4, 2020 Report Share Posted November 4, 2020 In the human IFN-gamma plus kit, it suggests 0.22 um filter for the primary antibody solution, and 0.45 um filter for substrate. I am guessing the primary filtration would be to remove aggregates? What is the reason for filtering substrate? would 0.22 work for the substrate as well? or 0.45 work for the primary antibody filtration step. thank-you for the information! Quote Link to comment Share on other sites More sharing options...
Christian@mabtech.com Posted November 4, 2020 Report Share Posted November 4, 2020 Hi Wendy, welcome to the forum! When the ELISpot substrate sits in its brown bottle there is a low level of precipitate formed inside of the container over time. This can lead to artefacts if you add the substrate directly to an ELISpot plate. By pushing the substrate through a 0.45um filter, you remove precipitates and you avoid this potential problem. You could in theory also use an 0.22um filter for this process, but it builds up a lot of resistance since the smaller filter quickly gets clogged with precipitate. Its doable, but you have to push like crazy if you try to do 12ml in one go. In order to remove antibody aggregates you have to use 0.22um due to their small size. I believe 0.45 will be too large. Quote Link to comment Share on other sites More sharing options...
Guest Wendy Posted November 5, 2020 Report Share Posted November 5, 2020 Thank-you Christian Quote Link to comment Share on other sites More sharing options...
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