Fab-pHast products

Fab-pHast products bind to your primary antibody via a secondary antibody or Streptavidin cross-linked to a pH-dependent fluorescent reporter.  This fluorescent reporter increases intensity as the pH of its surroundings becomes more acidic, as evident when exposed to the environment inside a cell.

SLC46A3 as a Potential Predictive Biomarker for Antibody-Drug Conjugates Bearing Noncleavable Linked Maytansinoid and Pyrrolobenzodiazepine Warheads.
Kinneer K,  et al. Clin Cancer Res, 24 (24):6570-6582, 2018.

Objective:  To develop biomarkers to uncover the underlying mechanism of resistance by certain cell lines for ADCs.

Summary: Loss of SLC46A3 expression was found to be a mechanism of innate and acquired resistance to ADCs bearing DM1 and SG3376.

Dose:  For Lysosomal trafficking, ADCs were labeled with Fab-pHast human (Cat. #PH-01). Cells were incubated with 3 mg/mL of labeled ADCs at 37°C for desired time points and fluorescence quantified by flow cytometry.

pHast Ab Internalization Assay
Parental HEK-293 cells, and HEK-293 cells transfected with the p75 receptor, were plated in a 96-well plate overnight. Titrated 192-IgG antibody (Cat. #AB-N43) was incubated at RT with 50 nM of Fab-pHast Mouse (Cat. PH-02) for 20 min prior to addition to cells. Plates were incubated overnight to allow maximum internalization, but a few hours is sufficient for detection.

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