Activation-Induced Marker Assay
Overview
The activation-induced marker (AIM) assay is a flow cytometry-based method for detecting antigen-specific T cells. PBMCs are stimulated with antigen peptide pools, and responding T cells are identified by upregulation of activation markers (commonly CD25 and OX40 for CD4⁺ T cells, or CD69 and CD137 for CD8⁺ T cells) without requiring intracellular cytokine staining. The AIM assay captures all responding T cells regardless of cytokine profile, making it more inclusive than ICS.
Key Points from Literature
- AIM assay confirms DENV-specific Tph responses: In Ansari2025, CD25⁺OX40⁺ readout after stimulation with DENV megapools (covering all 4 serotypes) confirmed that both Tph (CXCR5⁻PD-1⁺) and cTfh (CXCR5⁺PD-1⁺) cells contain DENV-specific populations. The AIM assay was used alongside intracellular cytokine staining and FluoroSpot to validate antigen-specific T cell responses (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue, n=170 dengue cohort).
- DENV peptide pools from Sette/Weiskopf group: The DENV megapools used for AIM stimulation were developed by collaborators at the La Jolla Institute for Immunology, covering CD4⁺ T cell epitopes across all DENV serotypes (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue).
Contradictions & Debates
None documented in current wiki sources.
Related Pages
Peripheral Helper T Cell, Conventional Flow Cytometry, ELISpot