Antibody validation: All primary antibodies included in the panel are validated either by the vendor or internal validation. Strategies considered for antibody validation include: 1) knockout/knockdown of gene of interest, 2) independent antibody verification, 3) morphological validation by performing IF using single common protocol on human kidney and positive control tissue (lymph node, tumors etc), 4) morphological validation by a renal pathologist blinded to the antibody used and 5) counterstaining for additional markers of the same cell type.
Aperio scanned image of PAS-stained section of the entire biopsy is evaluated for tissue morphology and integrity.
Use 5 µm thick sections for staining. For better results, stain and ablate the tissue within 2 weeks of sectioning.
Entire biopsy is ablated with increments in approximately 3 mm2 area to complete ablation of the cortical and medullary regions. Regions with artifactual section damage are excluded.
Each IMC analysis includes a section from a reference kidney, both cortex and medulla (quality control), on the same slide as an internal standard.
IMC is performed on the Hyperion XTi imaging system. Prior to ablation of tissue, the machine undergoes routine tuning and calibration for mass spectrometric detection of all the heavy metals used in the antibody panel each time.
For each IMC ablation, the steps of antigen retrieval and cocktail hybridization will be confirmed by visual inspection of the resident cell type markers using mcd viewer to identify the nuclei, proximal tubules, glomeruli, thick ascending limb, distal convoluted tubules and collecting duct to confirm that the correct region was ablated and analyzed.