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Controls are the most important part of any multicolor flow cytometry experiment. When using multiple colors controls are needed to compensate for spectral overlap.  Fluorescence minus one (FMO) controls – cells or beads stained with all but one of the fluorophore. They are used to determine the spillover for each spectral emission. A mathematical method is then used to compensate – i.e. correct the spillover from each  fluorophore into other channels.

Each new color in a panel increases the chance of non-specific spillover into almost all channels.  FMO tubes negative for one of the fluorophores in the panel and gating are used to measure fluorescence from the target antibody.   This method is critical for removing the discrepancies that remain after compensating for all the colors. It is used in addition to compensation controls to identify gating boundaries and differentiate spillover emission when fluorophores are excited by multiple lasers.

FMO controls_INF Ga ,,a and TNF alpha

Flow cytometry can be used to gather a plethora of experimental data. Power and versatility have made it a cornerstone in modern vaccinology and immunology. It is an essential drug and vaccine efficacy testing. It is also a complext tool. Its complexities present challenges to generating reproducible and publishable flow cytometry data.

At IBT Bioservice we can design and execute your studies with a variety of panels using up to twenty-three colors. We have panels validated using mouse, human and non-human primate samples. We offer immunophenotyping of T-lymphocyte and B-lymphocytes, detailed multicolor evaluation of T-lymphocyte response to antigens and much more. Our expert staff is always available to guide you on markers and fluorophores selection for custom analysis of the specific cell subset of interest for your project.

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Learn about the range of services we offer focused on early R&D for drug, vaccine and supporting assay development

IBT Bioservice is a contract research lab with a variety of in vivo and in vitro testing services. In addtion to high throughput flow cytometry, we offer well characterized in vitro assays for a growing selection of viral and bacterial pathogens. Our in vivo offerings include viral and bacterial infection models, immunogencity testing, pharmacokinetics and toxicity testing. Our expert staff is available to asnwer your questions and to guide you.

For a free no-obligation consultation contact us at or call 240-778-6513

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Fig. 1 Survival after challenge with INFV H1N1 A/Pert/261/2009 (Tamiflu-resistant strain). Inoculum 1xLD90=1.0E+05 PFU/mouse
Survival after challenge with INFV H1N1 A/Pert/261/2009 (Tamiflu-resistant strain) 1.0E+05 PFU/mouse
Survival and weight change in BALB/c mice challenged with INFV A/ Texas/36/91 (H1N1) and treated with antiviral Osletamivir Phosphate (Tamiflu)
Lung viral load and Survival (30 % weight loss cut-off) in BALB/c mice challenged with INFV H3N2 A/HK/1/68.