Dear flowers, We stained cultured T cells with two different FITC-conjugated monoclonal antibodies against cell surface receptors. We clearly observed two populations on the FSC histogram. In one of the cases, the low FSC subpopulation had a higher FL1 intensity, whereas in the other case it was the other way around. The two subpopulations were about the same size. We checked the cells with fluorescence microscopy, and we found that the cells with the low FSC-high FL1 profile had a considerable amount of intracellular fluorescence. In the other sample in which low FSC cells had low FL1 intensity, no intracellular fluorescence was visible. The cells were stained on ice, and normally we do not observe intracellular fluorescence when cells are stained using the same protocol. The cells with intracellular fluorescence did not take up propidium iodide. I posted some figures about these samples on the web: http://www.dote.hu/users/nagyp/histograms/histograms.html Any suggestions as to why some antibodies are "internalized" on ice, whereas others are not? Peter
This archive was generated by hypermail 2b29 : Sun Jan 05 2003 - 19:01:04 EST