Iron(III) and Iron(II) induce selective aggregation of Ig-G in human plasma.

SAPORITO MAGRIÑA C; LOPEZ MONTAÑANA, L; RODRIGUEZ, A; PAGANO, G; FACIO, ML; REPETTO MG

Congreso; Reunión conjunta SAIC. SAI & FAIC, SAFIS 2022. LXVII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC), lXX Reunión Anual de la Sociedad Argentina de Inmunología (SAI) & 3er Congreso Franco-Argentino de Inmunología (FAIC), Reunión Anu; 2022

Fe(II) is released from the enterocytes into the plasma, oxidized to Fe(III) by ferroxidases and transported by transferrin. Non-transferrin bound Fe(III) is present in plasma at a concentration of 1 µM. This labile Fe(III) drastically rises in pathological conditions such as thalassemia, hemochromatosis, etc. Here we show that both Fe(II) and Fe(III) selectively precipitate IgG, yielding a detergent resistant aggregate (DRA). DRA are found in elder patients and may be relevant in pathology. However, their nature is unclear. Methods: Optic density (OD), Lowry assay, SDS-PAGE, proteinogram, Mass Spectrometry (MS). Results: Followed by OD, Fe(II) and Fe(III) induce aggregation of plasma proteins at concentrations lower than 25 µM. This was confirmed by protein quantification in the aggregate fraction (p