Signal change with time
I am planning to use CyTOF to analyse primary Chronic lymphocytic leukaemia cells in the setting of a clinical trial. While optimising my workflow, I noticed a change in signal in my most recent experiment, particularly affecting 144Nd & 145Nd. Attached is 2 plots of the same cryopreserved CLL sample, analysed recently and several months ago.
In my more recent experiment, there appears to be several very bright CD81 and IgD events, more than the experiment I performed several months ago. I repeated the experiment again and fast spinned my antibody cocktail (I was initially worried that there could be Ab conjugates) but still have the same result with these highly intense events in CD81 and IgD. I should also mention that the antibodies and my workflow has been exactly the same in both experiments.
Am I being overly pedantic here, and this could just represent batch variation across runs, or could there be an issue with my antibodies (my antibodies are <1 year old)?
Thank you
Troy