HEPATIC DISPOSITION AND TOXICITY OF CATIONIZED GOAT IMMUNOGLOBULIN-G AND FAB FRAGMENTS IN ISOLATED-PERFUSED RAT-LIVER

Colchicine-specific goat IgG and Fab fragments were cationized by cova lent coupling of hexamethylenediamine. The immunoreactivity of antibod ies was not changed following cationization, The interaction of I-125- radiolabeled native (nIgG and nFab) and cationized immunoglobulin G (c IgG) and Fab fragments (cFab) with liver was investigated using isolat ed perfused rat liver (IPRL) and isolated rat hepatic parenchymal cell s (PCs) and nonparenchymal cells (NPCs) in suspension. I-125-cIgG or I -125-cFab were more rapidly cleared from the perfusate than the corres ponding native proteins, Both cIgG and cFab declined biexponentially o ver time in the perfusate, In contrast, the native IgG and Fab decreas ed monoexponentially. The half-lives of the initial and terminal phase s were 5.2 +/- 1.6 min and 355.1 +/- 17.2 min for cIgG and 14.7 +/- 3. 4 min and 552.4 +/- 23.7 min for cFab, The terminal half-lives of nIgG (467.4 +/- 11.6 min) and nFab (880.1 +/- 39.6 min) were longer than t hose of cationized molecules. The biliary protein extraction ratio of cationized IgG and Fab was greater than that of native IgG and Fab: 0. 13% (cIgG), 0.02% (nIgG), 0.23% (cFab), and 0.17% (nFab), The uptake o f cIgG and cFab by both PCs and NPCs was dose-dependent and was about 6-fold and 8-fold higher than that of their native counterparts, respe ctively. Throughout the experiment, liver viability was determined, an d no toxicity was observed according to physiological analysis (bile f low rate, portal vein pressure, and pH) and biochemical analysis (gluc ose and hepatic enzymes: alanine transaminase, aspartate transaminase, lactate dehydrogenase) in perfusate.