CD81 and microglial activation in vitro: proliferation, phagocytosis and nitric oxide production

CD81 (TAPA), a member of the tetraspanin family of proteins, is upregulated by astrocytes and microglia after traumatic injury to the rat central nerv ous system (CNS). To further understand the role of CD81 in the microglial response to injury, we analysed the functional effects of a CD81 antibody, AMP1, on cultured rat microglia. We found that AMP1 suppressed microglial p roliferation in a dose-dependent manner. Furthermore, AMP1 stimulated myeli n phagocytosis, probably by opsonizing the myelin. The phagocytosis of late x beads, as well as the production of nitric oxide, were not significantly influenced by AMP1. These data indicate that CD81 is involved in an importa nt subset of microglial effector functions after CNS injury. (C) 2001 Elsev ier Science B.V. All rights reserved.