From a research paper:
FOLR1 autoantibody detection
The assay for identification of the presence and relative quantification of FOLR1 autoantibodies in serum samples was performed as previously published.41–43 Horseradish peroxidase (HRP) labelled anti IgG antibody (Cat#I8640 Sigma Aldrich) and IgM antibody (Cat#I8260, Sigma Aldrich) were used to detect IgG and IgM. Antibody-depleted sera (Sigma Aldrich) was used as negative control. Serum effect on blocking FA binding to folate binding protein was detected using HRP labelled FA (FA-HRP, Ortho-Clinical Diagnostics, Raritan, New Jersey, USA). FA in serum samples was removed as previously described. Unlabelled FA was spiked (0.01–2000 ng/mL) into stripped antibody depleted sera to generate the standard curve. The SuperSignal ELISA Femto Substrate (Cat#37074, ThermoFisher Scientific) was used as substrate for detection of HRP activity. Images were collected using a 96-well imager (Q-View Imager, Quansys Biosciences). Intensities were extracted from the images using Q-View Software. IgG, IgM and relative FA-blocking amount were calculated based on the standard curves.
What is the meaning of "stripped" in stripped antibody depleted sera? I think that "antibody-depleted sera" stands for "serum samples that contain a reduced concentration of antibodies". But why stripped? Does it mean that the authors applied some additional techniques to ensure an even lower level of antibodies in the serum samples?
I found it odd because the word "stripped" is used only in this particular place, and nowhere else. They mention 'antibody-depleted sera" earlier, without "stripped".