Properties of Fc gamma receptors in the human central nervous system.

Cryostat sections of human central nervous system (CNS) tissue absorbed sheep erythrocytes (E) sensitized with rabbit IgG antibody (A). The indicator cells bound to the choroid plexus, to the leptomeninges covering the brain and spinal cord, to the arachnoid granulations and to the perivascular tissue of the neural parenchyma. Unsensitized E or E sensitized with F(ab')2 fragments of IgG were not bound. The reactions were inhibited by pooled human IgG, human IgG1 and IgG3 myeloma proteins, and Fc fragments of pooled human IgG. Whole human IgG2 myeloma protein, IgM, IgA, F(ab')2 fragments of pooled human IgG and albumin did not inhibit. Experiments with reduced and alkylated IgG, EDTA, iodoacetamide, 2-mercaptoethanol, various pHs and salt concentrations, formaldehyde, periodic acid and neuraminidase did not reveal any differences between the Fc gamma receptors in the separate anatomical areas. The Fc gamma receptors in human CNS are thus apparently very similar.