I have run a mixed lymphocyte reaction assay, using PBMCS and added BrdU after 5 days prior to reading out the assay by a BrdU ELISA today (12-24 hrs after adding BrdU). Unfortunately the ELISA kit has now gone missing so I can't run the ELISA. My plan is to remove BrdU, then lyse the cells using cytofix/cytoperm kit, and then to freeze down the lysates at -80C. My new kit will apparently be arriving in 48hrs. Is freezing the best plan? Or keep lysates at 4C/ -20C? Or freeze down the actual cell pellets rather than lysing? Any other suggestions please?