Effect of cytokines and lipopolysaccharides on HIV infection of human macrophages.

Human blood-borne monocytes (MO) differentiating into mature macrophages (MAC) were cultured on hydrophobic Teflon membranes. The cells were infected with two different monocytotropic HIV isolates: HIV1D117III obtained from a perinatally infected child, and HIV2D194 obtained from an AIDS patient who suffered exclusively from neurological symptoms. Virus production monitored by reverse transcriptase activity and HIV-antigen ELISA in cell-free supernatant was of a high level and continued for several weeks. To investigate possible modulatory pathways interfering with HIV infection in MAC we tested various recombinant cytokines as well as bacterial lipopolysaccharides (LPS) in our culture system. Whereas interleukin-1 (IL1) accelerated and increased HIV replication in MO/MAC, the interferons (IFN) alpha, beta and gamma effectively suppressed or delayed infection depending on the concentration used. Suppression was seen at concentrations as low as 0.3 U/ml and was most effective when the IFN were given prior to infection. No effect was observed with IL6 up to 2,000 U/ml. LPS affected virus infection in a complex manner: at 1-100 ng/ml virus replication was inhibited, but it was enhanced at subnanogram concentrations (25-100 pg/ml).