ImmunoSpot® Analyzers

The ImmunoSpot® Double Color Enzymatic Software Suite permits precise counting of single-color spots for either analyte, as well as double color spots produced by cells that co-express both analytes (J. Immunol. 2000, 164:1862). CTL offers a wide selection of double color enzymatic ELISPOT kits enabling such dual color enzymatic ELISPOT analysis. Learn more about double color enzymatic ImmunoSpot® analysis.

BioSpot™ enables ImmunoSpot® Readers to evaluate of broad range of neutralization assays and colony counting. Learn more

Enabled by the BioSpot™ Software, these readers can distinguish and count independently objects/colonies of up to 12 different colors as visible under white light illumination. Learn more.

Immune monitoring efforts frequently involve measuring serum antibodies' efficacy in neutralizing viruses, bacteria or toxins. ImmunoSpot® readers fully support such high throughput measurements, including foci and colony counting. Each type of colony, foci or viral plaque has unique morphologies requiring specialized image analysis solutions. The BioSpot™ Software Suite was designed to meet this challenge. The BioSpot™ Software can distinguish foci/colonies in up to 12 different visible color planes with white light illumination.

Learn more about the full spectrum of assays that can be analyzed with the BioSpot™ Software, and the software itself.

In addition to being able to scan microtiter plates of various well formats, and haemocytometers, ImmunoSpot® Readers can also scan histologic slides. In particular, tissue microarray scanning and analysis is to mention here. In this approach, tissue sections of regular size and shape are spread out on histologic slides in an array format, permitting the high throughput analysis of histologic and molecular changes in healthy or diseased tissues for diagnostic and research applications. See an example of such an image, here.

Cytokine arrays can be visualized with precipitating substrates. A sample image of this assay is printed into a well of a 96 well plate is shown below.

Cytokine arrays can be visualized via fluorescent detection reagents A sample image of this assay is printed into a well of a 96 well plate is shown below. CTL’s ImmArray Software permits high throughput-analysis of such assay results.

Zoom lenses enable image capture at maximal resolution using different magnifications/well formats. The zoom range of lenses used in high-end ImmunoSpot® Readers extends to the microscopic scale enabling high resolution analysis of single cells. See examples of cells imaged on ImmunoSpot® Readers. Readers without optical zoom capabilities are also suited to enumerate fluorescence-labeled individual cells, however, such instruments do not provide subcellular detail.

Applications include:

• Proliferation assay
• Viability assay
• GFP/RFP detection
• Apoptosis assay
• Cell cycle assays
• 6-color staining
• High content imaging
• Whole slide/mount imaging

Learn more about fluorescence-enabled single cell analysis applications of ImmunoSpot® readers.

Zoom lenses enable image capture at maximal resolution using different magnifications/well formats. The zoom range of lenses used in high-end ImmunoSpot® Readers extends to the microscopic scale enabling high resolution analysis of single cells. See examples of cells imaged on ImmunoSpot® Readers. Readers without optical zoom capabilities are also suited to enumerate individual cells, however, such instruments do not provide subcellular detail.

Starting June 1st 2023, CTL is providing a barcoded ELISPOT reference plate with every Analyzer delivery. The ExpressQualify™ tool automatically scans and counts the reference plate to verify that the Analyzer is still performing within factory specifications. To meet formal regulatory requirements and documentation, please consult our full-version ImmunoQualify™ package.

Zoom lenses enable image capture at maximal resolution using different magnifications/well formats. The zoom range of lenses used in select ImmunoSpot® Readers extends to the microscopic scale enabling imaging of single cells for live/dead/apoptotic cell counting, or for the detection of immuno-stained or transfected cells. See examples of cells imaged on ImmunoSpot® Readers.

Zoom lenses enable image capture at maximal resolution using different magnifications/well formats. The zoom range of lenses used in select ImmunoSpot® Readers extends to the microscopic scale enabling imaging of single cells for live/dead/apoptotic cell counting, or for the detection of immuno-stained or transfected cells. See examples of cells imaged on ImmunoSpot® Readers.

CTL instruments are equipped with software-controlled top and bottom white light sources, each independently gradable, which permits the optimization of well illumination for different assay formats.

About 1,000 of our ImmunoSpot® Readers operate in a regulated environment, having satisfied in house and third-party audits, including audits of regulatory agencies. An optional ImmunoCompliance™ package is available. We offer IQ, OQ for our regulated customers. Learn more.

Automated, plate loading solutions are optional upgrades for CTL readers. Our stackers enable scanning and counting up to 50 plates in a run, while with our robotic arm solution up to 400 plates can be analyzed as a single batch.
Watch Demo Video

ImmunoSpot® Readers are frequently run in BSL 3 and even BSL-4 environments. These instruments’ skin and interior has been designed to withstand and facilitate disinfection.

See CTL employee servicing an ImmunoSpot® Reader in a BSL4 laboratory here.

Select ImmunoSpot® Readers have been engineered such that the number of narrow-band excitation light sources, fluorescent cubes and filters can be modified after the instrument was installed to increase the number of fluorescent channels (colours). In this way, customers have the flexibility to adjust their instruments to future needs.

An integrated keyboard tray and monitor reduces the foot print of the system by half as compared to the bench space needed if the analyser, monitor and keyboard are set up next to each other.

The spot counting accuracy of the ImmunoSpot® Single-Color ELISPOT Enzymatic Software Suite is based on rigorous experimental validation. This software implements “a single click of a button” InteliCount™ algorithm that is based on 25 years of leading scientific expertise in ELISPOT analysis captured in deep machine learning-assisted object recognition. In “expert” mode, this software enables scientists to perform high-content analysis based on spot sizes and morphologies, for example, to establish per cell productivity and affinity distributions of antigen-specific B cells. Built-in user authentication, audit trails and data security support transparent ELISPOT counting in a regulated environment. Spot recognition in the ImmunoSpot® Software is based on principles described in our patent (US Patent 6,410,252 B1; filed 12/95).
Learn more.

Two color ELISPOT analysis can be performed using precipitating substrates that have distinct color spectra with visible/white light illumination (without involving fluorescence).

The ImmunoSpot® Double Color Enzymatic Software Suite permits precise counting of single-color spots for either analyte, as well as double color spots produced by cells that co-express both analytes [Journal of Immunology. 2000, 164:1862]. CTL offers a wide selection of double color enzymatic ELISPOT kits enabling such dual color enzymatic ELISPOT analysis. Learn more about double color enzymatic ImmunoSpot® analysis.

Enabled by CTL’s ODense™ Software Suite, ImmunoSpot® Instruments are capable of reading ELISA results in addition to nucleic acid and protein quantification. The streamlined workflow integrates planning and plate layouts with automated graphical outputs and statistical analysis tools. The work flow is streamlined from planning the plate lay-out to automated generation of the graphs, and the statistical analysis of the results. 21 CFR Part 11 compliant QC and audit trails support work in a regulated environment.

CTL’s philosophy is to offer instruments that support several functions commonly performed in immune monitoring laboratories, saving our customers the expense of having to purchase and maintain a dedicated instrument for each, all included in the cost of a single device.

High throughput analysis is streamlined by the SpotMap™ Software Suite. In the assay-planning phase, plate layouts are created, and barcodes are generated for each plate. SpotMap™ links the spot counts for groups of repetitive wells (e.g. triplicates) to the donor sample IDs and antigens present in those wells, and passes on this information for automated statistical analysis and subsequent export to any standard database. With SpotMap™ complex assays can be evaluated “at a click of a button”.

The Image Annotator™ facilitates image analysis-oriented exchange between scientists themselves, or scientists and CTL's expert support team. Regions of interst on a well image are marked and annotated. This information along with the raw image and the counting parameters are bundled together to be passed on for discussion or consultation.

The SpotStat® Software Suite was developed for the statistical analysis of ELISPOT/Fluorospot data in immune monitoring, vaccine testing, and other fields of immunological or medical research.  SpotStat® implements a number of powerful parametric and non-parametric statistical methods for easy, streamlined analysis of data generated by CTL’s ImmunoSpot® platform. Learn More

The Reagent Tracker™ Suite provides audit trails for the accurate implementation of ELISPOT/FlouroSpot assays, revealing pipetting errors made (https://doi.org/10.3390/cells7010003). Biologically neutral dyes are used to colour different antigens and the Reagent Tracker™ Software checks whether in each assigned well the right antigen/colour has indeed been plated (revealing qualitative pipetting errors), and whether the antigen pipetting volume was correct (revealing quantitative pipetting errors). The Reagent Tracker™ Suite generates automatic printable reports and is also ideally suited for proficiency testing of lab personnel, and for training of novices in the lab.

CTL has been committed to elevating ELISPOT/FluoroSpot assays so they can meet regulatory requirements for transparency and audit trails. The Reagent Tracker™ Suite is one of the important steps in that direction.

The ImmunoQualify™ Tool permits to verify main functions of ImmunoSpot® Readers and assures accurate performance before each use, or periodically. At the “press of a button”, a Reference Plate is scanned, and the newly established counts are compared to the factory-established reference counts for that plate, generating a pass/fail report.

CTL’s ImmunoCompliance™ Package includes a two-tier offering. To learn more, please follow this link.

Most fluorochromes have partially overlapping spectra. For multicolor analysis, ImmunoSpot® Readers are designed such that select fluorochromes can be detected simultaneously in the same well without cross-bleeding of colors from one fluorescent channel to the another, thus permitting unambiguous identification of each analyte, as well as of multiple analyte co-expressing cells. Customization of assay-specific excitation/emission filters are available upon request.
Learn more.

Most fluorochromes have partially overlapping spectra. For multicolor analysis, ImmunoSpot® Readers are designed such that select fluorochromes can be detected simultaneously in the same well without cross-bleeding of colors from one fluorescent channel to the another, thus permitting unambiguous identification of each analyte, as well as of multiple analyte co-expressing cells. Customization of assay-specific excitation/emission filters are available upon request.
Learn more.

ImmunoSpot® detects the individual fluorescent colours/labels without cross-bleeding. A “center of masses distance algorithm” compares spot center coordinates in each fluorescent channel to identify analyte co-expressing subpopulations of cells. The number of subpopulations showing a distinct analyte co-expression profile is specified here. Learn more.

Enabled by CTL’s LDA Cell Counting Suite, fluorescence capable ImmunoSpot® Readers are rendered into image-based cell counters, saving our customers the expense of having to purchase and maintain a dedicated cell counter, all included in the cost of a single instrument. Fluorescent dyes with non-overlapping colour spectra are used for live/dead/apoptotic (LDA) cell staining. LDA counting of 96 PBMC samples takes just minutes including automatic calculations of resuspension volumes and generation of audit trails and a concise report.
Learn more about 96 well-based high throughput PBMC counting.

Learn more about the formal validation of CTL’s Live/Dead PBMC counting platform.

Learn more about our LDA cell counting Suite.

Select ImmunoSpot® Readers are suited to measure the lysis of fluorescent dye-labelled target cells in 96-well or Terasaki plate format (Ref., and view presentation). Such target cell visualization assays (TVA) are commonly used for measuring natural killer- (NK) cell-mediated cytotoxicity, or of antibody-dependent cell-mediated cytotoxicity (ADCC). Enabled by CTL’s TVA Software suite, such ImmunoSpot® Readers provide the results nearly 10x faster and streamlined than the fastest flow cytometers.

Measuring cell-mediated cytotoxicity is part of the assay repertoire of most laboratories involved in immune monitoring efforts. CTL’s philosophy is to offer instruments that support several functions commonly performed in immune monitoring laboratories. Enabled by CTL’s TVA Software suite, ImmunoSpot® instruments can measure NK-dependent cytotoxicity, saving our customers the expense of having to purchase a dedicated instrument, all included in the cost of a single device.

Most fluorochromes have partially overlapping spectra. For multicolor analysis, ImmunoSpot® Readers are designed such that select fluorochromes can be detected simultaneously in the same well without cross-bleeding of colors from one fluorescent channel to the another, thus permitting unambiguous identification of each analyte, as well as of multiple analyte co-expressing cells. Customization of assay-specific excitation/emission filters are available upon request.
Learn more.

Enabled by the BioSpot™ Software, these readers can distinguish and count independently objects/colonies of up to 12 different colors as visible under white light illumination.
Learn more

The accurate evaluation of multicolor B-cell and T cell FluoroSpot assays, , each require different image analysis approaches for identifying single or multiple analyte-secreting cells. Spot recognition in the ImmunoSpot® Software is based on principles described in our patent (US Patent 6,410,252 B1; filed 12/95). In the FluoroX™ software, deep machine learning assists the detection of secretory footprints of interest.

Learn more

CTL’s LDA Cell Counting Suite enables high-throughput live/dead/apoptotic (LDA) cell counting with suitable ImmunoSpot® Readers. CFR Part 11 compliant QC and audit trails support cell counting in a regulated environment.
Learn more.

In this approach, tissue sections of regular size and shape are spread out on histologic slides in an array format permitting the high throughput analysis of histologic and molecular changes in healthy or diseased tissues for diagnostic and research applications. Readers can be used to scan such tissue microarrays under visible or multicolor fluorescent light. See examples of such images, here.

ImmunoSpot® Readers are multifunctional imaging instruments. They permit high throughout reading of a wide range of microtiter plate and petri dish formats with back- and/or top light, or fluorescence. Dedicated software permits analysis of ELISPOT/FluoroSpot, viral-, bacterial-, and yeast colony counting, as well as single cell imaging for various infectivity-, gene expression-, and cytotoxicity assays. Satellite software licenses are available enabling the individual laboratories to analyze the data on their own, independent of the core instrument/facility.

The Target cell Visualization Assay (TVA™) Suite is a high-throughput cell counting application that is designed to measure the lysis of fluorescence-labelled target cells in a 96-well or Terasaki plate format. The TVA-Suite enables streamlined work flow from planning the experiment to automated generation of graphs with audit trails supporting work in an academic or regulated environment.
Learn more.

Traditionally, ex vivo proliferative T cell responses elicited by recall antigens or other stimuli have been measured by the ³H-thymidine incorporation assay. There are two non-radioactive alternatives. One, is the MTT assay. It is a colorimetric test, that can be readily read with CTL’s ODense^TM Software installed on each of our reader models. The other method relies on counting cell clusters, so called morulas, that form in wells when T cells proliferate. To learn more about the latter, please see this video recording.

Florescence-capable CTL Readers can also measure proliferation via assessing CFSE dilution. The CFSE dye binds covalently to long-lived molecules present inside the cell. When the parent cell divides, the first generation of two daughter cells “inherits” each half the dye, the second generation one fourth. This quantal decrease in per cell staining intensity can be evaluated by our Fluoro-X® Software that is installed on all of our fluorescence-capable readers.