The CODEX Assay overcomes challenges of traditional multiplexed immuno-fluorescence, by targeting subsets of the antibody panel through iterative imaging cycles.
The CODEX Assay uses antibodies conjugated to molecular Barcodes in the form of unique oligonucleotide sequences. This enables customizable panels of up to 50 CODEX Antibodies to be combined for a single tissue staining reaction. Corresponding dye-labeled Reporter sequences are used to target subsets of the Barcodes.
For each imaging cycle, three CODEX Reporters, each with a spectrally-distinct dye, are applied to the stained tissue to assay the corresponding Antibody Barcode. The tissue is imaged, revealing the fluorescence signal levels of the first three targets plus a nuclear stain. The CODEX instrument applies gentle wash steps to remove the Reporters without any chemical modifications, followed by applying the next set of Reporters. In this manner, more than 50 parameters can be measured in a single tissue specimen
Cycle 1: CD8 – CD19 – CD90 Cycle 2: CD21 – CD3 – CD54
Cycle 3: CD49f – CD63 – Ki67 Cycle 4: CD38 – CD5 – CD279
Human tonsil germinal centers imaged in four cycles with three markers per cycle.