We are focused on four main immunoassays: ELISpot, FluoroSpot, ELISA, and FociSpot. They are sensitive methods, useful for answering questions on specific immune responses.
We like them all, for the various reasons described below.
To learn what product format suits you best,
go to Product guide.
If one cell responds, you will find it
The enzyme-linked immunospot (ELISpot) assay is an extremely sensitive immunoassay performed in a 96-well plate format to quantify protein-secreting cells.
The assay principle is straight forward: cells are cultured and stimulated inside a plate coated with capture antibody. Cytokines, immunoglobulins, or other target proteins secreted by the cells are captured immediately upon secretion and throughout the stimulation process. After cell removal, secreted proteins are identified using a detection antibody. Visible spots form after adding a precipitating substrate. Each spot corresponds to an individual analyte-secreting cell.
With minimal manipulation of the cells, ELISpot lies closer to reality than most other cell-based immunoassays down to the single-cell level. Due to capacity to find one cell in a million, ELISpot is particularly valuable for studies of rare cell populations causing immune responses.
Tell the story of every cell
FluoroSpot is the multiplex version of ELISpot. Just like in the ELISpot assay, target proteins secreted by cells are captured by specific antibodies immediately after secretion and throughout the stimulation process, making it an extremely sensitive sandwich assay. The difference to ELISpot lies in the mode of detection: where ELISpot relies on an enzymatic reaction, FluoroSpot utilizes fluorescence. This opens up for multiplex analyses of several analytes simultaneously, enabling studies of cell populations with different functional profiles.
Like ELISpot, FluoroSpot is useful in e.g., vaccine research and evaluation of cancer immunotherapies, but gives a broader picture of the response by enumerating highly functional triple-secreting IFN-γ/IL-2/TNF-α cells, or killer cells secreting IFN-γ and Granzyme B simultaneously.
Ready for reality
ELISA is a straightforward research tool for quantifying analytes in solution. The analytes measured are proteins, such as cytokines, chemokines, immunoglobulins, hormones, or other biomarkers. Typical samples are cell supernatants, plasma, serum, and other bodily fluids. The uncomplicated detection procedure and the versatility of sample choice strengthen the broad use of ELISAs across research fields and diagnostics.
To get the most out of your ELISA experiment, please read our Step-by-step guide to ELISA.
Count foci with ease
FociSpot is our new assay platform that includes both kits and a brand-new analysis capability of Mabtech IRIS™ 2 allowing for automated counting of foci in a 96-well plate format. Focus forming assays (FFAs) can have a variety of different setups for different research goals such as focus-reduction neutralization tests (FRNT) or Tissue Culture Infectious Dose (TCID50) assays. FRNT and TCID50 can be used to quantify viral titers or virus-specific antibody neutralization titers and are commonly used in vaccine and infection research. We know that each viral assay is unique, though, using different cell lines, media, and viruses, but counting foci doesn’t have to be. In these assays, foci are detected with immunostaining using virus-specific mAbs and a precipitating substrate reaction similar to ELISpot. The developed foci can now be easily counted using the FociSpot application in IRIS 2.
We've even developed our very own virus-specific FocisSpot kits that can be used to detect virus-specific foci. Based on the same development principles of ELISpot, we utilize a biotinylated virus-specific detection mAb followed by a precipitating enzymatic reaction to visualize foci. Can’t find your virus of interest? We have the reagents needed to set up your very own virus-specific FociSpot development.
FociSpot assay principle
Increasing dilutions of SARS-CoV-2 added to cells and detected with FociSpot