For my experiment we infect B6 mice with Plasmodium berghei parasites (IP injection) and after 6 days we measure the percentage of infection = the amount of red blood cells that are infected with our parasites. Last time we did this by making a Giemsa stain of a blood smear from the infected mice. Because this is so much work we were looking for a faster method to determine parasitemia. This week I tried labeling with sybr green. So I took a drop of blood from the mice, added sybr green and CD45 (to stain lymphocytes) and then measured the sample by flow cytometry. The first experiment was fine, I got about the same percentages of infection on the FACS as by counting on the microscope. However, today the results were really bad and I don't now the reason. Does any one already has done this? Or does anyone knows another method to stain DNA of parasites to determine the percentage of infection by flow cytometry? Hoescht is unusable because we don't have an UV laser.
I hope someone can help ;-)