If you are doing flow cytometry using multiple channels, markers that are not expressed well, or a small amount of sample, the AbC™ bead kits from Life Technologies will definitely make your research life easier. These are compensation beads, comparable to BD Biosciences compensation beads. Instead of using cell sample for your single color compensation controls, you substitute these beads. Essentially these beads are polystyrene microspheres that are either coated with Ig (positive compensation beads) or uncoated (negative compensation beads).
I am a Post-Doctoral Fellow and a large part of my research involves characterizing rare and not so rare populations that infiltrate into the gut in response to infection. As you can imagine, immune cells present in the cecum can be low in numbers and when you are looking for rare populations, high cell counts are essential. Furthermore, I characterize about 17 different immune cell subsets using 4 different cocktails. In one particular cocktail, I use 9 different fluorophores. Needless to say, accurate compensation is an absolute necessity for my work.
These beads are pretty simple. Essentially one drop of the positive beads is added to a flow cytometer tube. To that add 1 µL of your antibody. Incubate for 15 minutes. Add 3mL of buffer then pellet the beads and resuspend in buffer and add 1 drop of negative beads and you are done.
The beads can be used multiple times. In my hands, these beads/antibody complexes were stable 3 months. Lets talk about savings! First, time is saved because you do not have to make new compensation controls every time you do flow (labeling tubes, spinning, and decanting). Second, reagents are saved (antibodies, buffers, tubes, and tips). Finally, you save sample. When compensating a rare marker on a rare population, you need a ton of cells to properly compensate. This eliminates that need and cells are used only for samples and not controls. More cells, more data.
Bonus! While BD Biosciences have a compensation bead, they sell the rat and hamster bead separately, whereas Life Technologies sells one bead for both rat and hamster antibodies (again saving money). Furthermore, I have tried the anti-rat/hamster beads with Syrian Hamster and Armenian Hamster isotypes. Also, the prices between BD and Life Technologies are basically the same. The Good: This work very well and save time and money The Bad: Upfront cost is about $500. The Bottom Line: The ease of compensation is worth every penny.
Graduate Student
Department of Microbiology and Immunology
Temple University