An in vitro model for the binding of polybrominated biphenyls in environmentally contaminated blood

Spiking blood with¹⁴C-labeled 2,2′, 4,4′,5,5′-hexabromobiphenyl (¹⁴C-HxBB) or a mixture of 2,2′,4,5,5′-pentabromobiphenyl, 2,2′,4,5′,6-pentabromobiphenyl and¹⁴C-HxBB has been found, in comparative measurements, to be a representative model of polybrominated biphenyl (PBB) contaminated blood from Michigan residents. Blood components were obtained by Ficoll-Hypaque techniques, apolipoprotein B and A fractions by immunoprecipitation with specific antisera; congeners were quantified by negative chemical ionization mass spectrometry or scintillation counting. The distribution of PBB among plasma, erythrocytes, mononucleocytes and polymorphonucleocytes was 89:9:≤1:≤1. In serum, 20% of the PBB was not bound to protein. The remaining 80% was bound to apolipoproteins B and A in a 4:1 ratio, which is close to the ratio (by weight) of the lipid content of these apolipoproteins. No preferential absorption of PBB congeners occurred in the examined blood compartments.