Design on What Was Actually Done

Visual Summary: Design and analytical roadmap for robust AIM assays

Interactive workflow graph: AIM plus ICS combined assay decision tree

Design recommendations and critical controls (visual first then explanation)

• Stimulation duration — 16 to 20 hours overnight for AIM readout to maximize surface marker upregulation while preserving cytokine secretory capacity for subsequent ICS; if collecting secreted cytokines, collect half supernatant before addition of protein transport inhibitors Oxford Open Immunology combined AIM ICS
• Marker selection and panel design — Use at least two AIM markers per lineage (eg OX40 plus CD137 for CD4; CD137 plus CD107a or CD69 for CD8); include activation induced PD-L1 or ICOS for specialized subsets (Tfh/GC Tfh) and dump channel for lineage exclusion. Validate background using DMSO and strong polyclonal control (SEB/PHA) J Immunol AIM primary paper
• Protein transport inhibitors timing — Add brefeldin A and monensin plus anti CD137 antibody approximately 2 to 4 hours before harvest when combining AIM and ICS; if using anti CD137 during stimulation to capture transient expression, titrate so it does not block function Combined AIM ICS timing study
• Negative and tetramer controls — Per-donor DMSO background wells and, where available, MHC class II/ I tetramers or peptide pool positive wells (CMV/EBV/Flu) to confirm specificity; include unstimulated and irrelevant peptide pools to quantify bystander activation CHIKV AIM raw flow files
• Data acquisition and analysis — Acquire 500 000 to 1 000 000 events per sample when rare antigen specific cells expected; analyze with automated high-dimensional gating or supervised templates to reduce operator bias (PlateAnalyzer/FlowJo plugins or scripted FlowKit pipelines) Flow cytometry analysis alternatives

Practical experimental protocol (concise stepwise checklist)

Defining responder thresholds and statistics

Use donor matched DMSO background subtraction and define positivity as three criteria: (1) frequency after subtraction >0.01 percent of parent CD4 or CD8, (2) magnitude exceeding mean plus 3 SD of negative controls run in same batch, and (3) reproducible across technical replicates; report both frequency and stimulation index. Where possible verify with tetramers or functional readouts. These practices follow recommendations and examples from AIM/ICS combined studies and epitope mapping datasets AIM gating and thresholds

Common pitfalls and troubleshooting

• Anti CD137 antibody added too early can mask or block receptor dynamics — titrate and validate in pilot runs Anti CD137 timing
• Low event counts reduce power to detect rare AIM cells — acquire high event counts and/or sort and expand for downstream assays CHIKV AIM raw data
• Supernatant collection before BFA can be used to pair secreted cytokine multiplex readout with cellular AIM detection without impairing detection when done as validated Supernatant handling in combined AIM ICS

Advanced extensions

1. Couple AIM sorting with single cell RNAseq or TCRseq to pair functional state with clonotype (examples and data available from published epitope mapping studies) CHIKV epitope mapping with AIM
2. Use spectral flow or CyTOF to expand AIM phenotyping to 20+ markers and map differentiation, exhaustion, and tissue-homing signatures for mechanistic insight CyTOF and AIM contextualization

Minimal reporting checklist for publications and QC

• Donor numbers, viability, cell numbers/well, peptide conc, negative/positive controls, stimulation/time, BFA/monensin timing, antibody clones and catalog numbers, acquisition events, gating strategy and FMO controls, responder definition and statistical threshold — include raw .fcs when possible Raw AIM .fcs deposit example

Confidence note: Recommendations are synthesized from peer reviewed AIM method papers and recent datasets; key limitations include interlab variability in antibody clones, donor heterogeneity, and choice of peptide or protein antigen which can alter sensitivity — always run pilot validation experiments per site and reagent lot Flow cytometry automation and QC

If you would like a fully individualized experimental design (including reagent tables, antibody clones and lot-level titration plan, plate maps, power calculations for donor numbers, automated FlowJo and FlowKit gating scripts and an optional single cell RNAseq integration plan) run the biology AI agent using the Run AI Biology Analysis button above. For iterative research evolution click Evolve Response to refine scope and reproducibility.