5] Nonstandard abbreviations: PAPP-A, pregnancy-associated plasma protein A; ACS, acute coronary syndrome; proMBP
, proform of eosinophil major basic protein; FPAPP-A, free form of PAPP-A; TPAPP-A, total PAPP-A; cTnI, cardiac troponin I; ECG, electrocardiogram; CRP, C-reactive protein; FDA, US Food and Drug Administration; RR, risk ratio.
We analyzed the effect of increasing concentrations of PAPP-A/proMBP by the addition of purified PAPP-A/ proMBP (0 to 180 mg/L) to a reaction containing 1 nmol/L active PAPP-A.
QF-II was cleaved efficiently by recombinant PAPP-A, but not by an inactive mutated PAPP-A variant (E483Q) (25) or PAPP-A/ proMBP complex purified from pregnancy serum (21) (Fig.
The PAPP-A/proMBP assay imprecision was studied with pooled pregnancy serum diluted with BSA-TSA buffer to achieve PAPP-A/ proMBP concentrations relevant in ACS (mean PAPP-A/ proMBP concentrations, 3.
The calibration curves for the total PAPP-A and PAPP-A/ proMBP assays are shown in Fig.
4] Nonstandard abbreviations: PAPP-A, pregnancy-associated plasma protein-A; IGF, insulin-like growth factor; proMBP
, proform of eosinophil major basic protein; PAD, peripheral arterial disease; tHcy, total homocysteine; (hs-)CRP, (high-sensitivity) C-reactive protein; and eGFR, estimated glomerular filtration rate.
We have characterized PAPP-A extracted from atherosclerotic plaques and have found that plaque PAPP-A is also not complexed with proMBP.
mAbs B5, B6, and A11 were known from previous studies to react with the proMBP subunit of the PAPP-A/ proMBP complex (12,15, 23, 24).
3] Nonstandard abbreviations: PAPP-A, pregnancy-associated plasma protein A; proMBP
, proform of eosinophil major basic protein; IGFBP, insulin-like growth factor-binding protein; DS, Down syndrome; BITC, biotin isothiocyanate; BSA, bovine serum albumin; mAb, monoclonal antibody; TSA, Trissalineazide; and Hct, hematocrit.
The synthesis of ProMBP is known to occur in cells other than placental X cells and eosinophil precursor cells (18), but whether ProMBP or MBP is released into the circulation from these sources is unknown.
In this study, we developed and characterized a sandwich immunoassay for ProMBP/Ang complexes and developed assays for ProMBP/C3dg complexes and the total concentration of ProMBP complexes to study their relationship with ProMBP/Ang complexes.
The monoclonal antibodies used in this study were Hyb234-2, Hyb234-3, Hyb234-4, Hyb234-5, and Hyb234-6, all raised against PAPP-A/ proMBP
complex purified from term serum and all type IgG1.