Dear Ali, to achieve the best quality in your research you need to analyze freshly obtained samples immediately.

The best method would probably be to fix your cells with 1.5% formaldehyde and then store them frozen. Depending on what markers you are hoping to phenotype, it might be more reliable to stain them first prior to fixing and freezing them.

Thank you for your response. I would like to study the CD3, CD4, CD8, CD45, CD127, CD125. Also my sample in not enough and i need to pool out all my collected sample then do the immunophenotyping. I plan to use FC.

You should be ready to see decrease in fluorescence intensity after fixation. In addition, you will not be able to use tandem dye conjugated antibodies. The risks to obtain artefacts are greatly enhanced. The most probably, this will result to loss of money.

store them fixed with methanol as a pellet in -80°c then stain when you want. I would nevertheless recommend freezing live cells as above in DMSO. You will loose cell numbers but preserve nice stainings.

ps you need to validate your antibodies with methanol first

I agree with Margit Lampen with one addition. When doing your flow cytometry, include a dead cell stain to exclude them from the analysis as they will stain aspecifically with your mAb.

Good luck.