Macrophage function in alloxan-diabetic mice: expression and activity of Fc receptors.

The expression of Fc receptors (FcR) on macrophage surfaces is dependent on the in vitro insulin level. Macrophages (Mø) of alloxan-diabetic animals have more FcR and phagocytose heavily opsonized sheep erythrocytes (SRBC) better, than normal Mø. The reverse is, however, true when suboptimally opsonized SRBC are used. No differences were found between normal and diabetic macrophages in the rate of catabolism of engulfed antigen. We regard it likely that the generation and/or transmission of Fc-dependent signal from the cell surfaces may be impaired in hypoinsulinaemic environment.