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ELISPOT/FluoroSpot Proficiency Testing

Within peripheral blood mononuclear cells (PBMC) of each human subject there is a defined number of T or B cells that are specific for any given antigen, and each of these T or B cells exerts a defined effector function by secreting a certain cytokine/cytokine pattern or antibody class/subclass, respectively. This number of T or B cells is absolute. Unambiguously defining it is the scope of immune monitoring, but establishing it requires all assay parameters to be maximized. By participating in CTL’s Proficiency Testing, you can verify your ELISPOT/FluoroSpot assay proficiency, and establish whether your test protocols, reagents, conditions and analysis criteria have been optimized.

CTL Proficiency Testing is available for human antigen-specific CD4 or CD8 T cells secreting either IFN-γ, IL-2, IL-4, IL-5, IL-17, IL-21, granzyme B, or perforin individually, or co-expressing these analytes in multi-color assays, in combination. For antigen-specific human B cells, testing of immunoglobulin classes and subclasses is offered, individually or in any combination.

Participants of CTL Proficiency Testing receive cryopreserved PBMC samples of two human donors that have been pre-characterized at CTL for the antigen-specific T or B cell subpopulations in question. Antigens, reagents and protocols are also provided. The central hypothesis is that testing of the same PBMC samples using identical test conditions should provide identical results; if the results differ, in that case either handling of the PBMC or evaluation of the results must account for the difference. To account for the latter, the plates are to be analyzed both at the participating site, and at CTL, using the very platform that was used to generate the reference data. If the counts match up, this proves that the performance of the assay was implemented correctly at the participating site; if the counts do not match, then the handling of the PBMC is the only variable that can explain the difference.

Next to testing the reference PBMC relying on CTL’s ImmunoSpot® platform, participants are encouraged to test these cells relying on their laboratory’s preferred protocols and reagents. If the test results are comparable to, or better than those obtained using the ImmunoSpot® platform, then the proficiency of the participant’s assay performance is also proven.

Proficiency Testing concludes with a one-on-one discussion of the test results.

There is no registration deadline; you can initiate CTL Proficiency Testing any time. Within a month the Proficiency Testing can be completed, including the issuance of a certificate.

Proficiency Testing costs USD 1,500 per analyte.