IP-MALDI-MS assay LOD for VP40 by targeting two peptide variants

We developed a quantitative assay for carefully selected VP40 peptide variants. We selected two peptides, LGPGIPDHPLR from EBOV VP40 and LRPILLPGK from BDBV VP40 to generate pan-peptide variants antibodies. Potential structural difference in virion particles affect the efficiency of VP40 liberation during sample inactivation, and the sequence variations also affect the affinity of peptide against the pan-variants antibody. Therefore, we quantified the mass contents of VP40 in EBOV and SUDV VLPs and used the VLPs from each species to build the species-specific standard curves. This improves the accuracy of VP40 quantitation. The feasibility of using miniature mass spectrometer to collect the tandem MS spectra for both peptides was validated.