Dear Flowers, I have been working with Flow cytometry for the last 3 years but have only recently become aware of this discussion group. I am investigating the effects of increasing tumour burden on mouse spleenocyte subsets and function. On initial flow analysis there are two main populations of cells 1) the morphologically lymphocyte population and 2) a second population that have a similar side scatter profile but a smaller forward scatter profile. This suspicious population of cells constitute 25 - 40% of the total population. However overall the cell viability by Trypan Dye Exclusion was 95%+. When non-fixed cells were analysed for permeability to Propidium iodide 16% of the suspicious population took up PI as compared to 3.5% of the morphologically lymphocytic population. When examined for phosphatidylserine expression with Annexin V 5% of the suspicious population were positive as compared with 1% of the lymphocyte population. When analysed for T cell antigen expression 57% of the lymphocyte population expressed CD3 as compared to 9% of the suspicious population. My question is have other investigators found this population of cells also? From the published reports I have not seen any reference to them. Would the consensus opinion be that these are dying rather than dead cells? I have looked at every aspect of cell preparation and they are a constant finding. Could they represent immature cells from the splenic follicles? I would apreciate any advice as to how to move this forward or if previous workers have encountered the same problem what there conclusions were. Thanks for your help. Mike O'Brien Dept. Of Microbiology, University College Cork, Cork, Ireland.
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:59:29 EST