Macrophage function in azocasein-induced amyloidosis in CBA/J and A/J mice

Abstract

It is known that a single gene governs resistance to amyloidosis induced by azocasein in A/J compared to CBA/ Jmice. We wished to determine whether this trait might be linked to differences in macrophage activation as measured by Feγ-receptor (Fcγ-R) and C3h receptor (C3b-R) phagocytosis of sheep erythrocytes and/or TNF secretion by adherent resident peritoneal cells. Macrophages from preamyloidotic and amyloidotic CBA/J mice showed marked enhancement of Feγ-R and C3h-R binding activity. Macrophages from A/Jmice receiving multiple azocasein injections showed a significant increase in Fcγ-R but not in C3b-Rphagocytic indices. Adherent peritoneal cells from control and azocasein-treated A/J Write produced higher TNF levels than control and azocasein-treated CBA/J mice. In both strains, peritoneal macrophage TNF secretion was depressed after 10 azocasein injections. Our findings differ from previous studies in which the amyloid deposition phase was associated with normal or depressed phagocytosis. On the oth...