Induction of human immunodeficiency virus type 1 replication in human glial cells after proinflammatory cytokines stimulation: Effect of IFNγ, IL1β, and TNFα on differentiation and chemokine production in glial cells

Although evidence for human immunodeficiency virus 1 (HIV-1) presence in the central nervous system (CNS) of infected patients is well established, the intensity of viral replication within the brain is not usually known. In vitro, human embryonic microglial cells internalized HIV-1 through a CD4-dependent pathway but were not permissive to viral replication. We observed that HIV replication was induced when CNS cell cultures were stimulated for 14 days by a combination of proinflammatory cytokines including IFNγ, IL1β, and TNFα. After long-term cytokine stimulation, morphologically differentiated glial cells appeared, in which HIV-1 tat antigen was detected after infection. Thus, variations in the stage of maturation/activation of CNS cells under inflammatory conditions probably play a major role in facilitating massive production of HIV-1. We then studied the effect of prolonged cytokine stimulation on the secretion of inflammatory mediators by glial cells. An early increased secretion of prostaglandin F2α and chemokines (RANTES>>MIP-1α>>MIP-1β) was observed, due to both microglia and astrocytes. In contrast to persistent PGF2α production, an extinction of RANTES and MIP-1β but not of MIP-1α secretion occurred during the 14 days of stimulation and was inversely correlated with the ability of glial cells to replicate HIV-1. The study of the secretory factors produced in response to a persistent inflammation could provide a better understanding of the modulation of HIV replication in glial cells. GLIA 23:304–315, 1998. © 1998 Wiley-Liss, Inc.