Reactivation of HIV type 1 in chronically infected chimpanzees following xenostimulation with human cells or with pulses of corticosteroid.

Following resolution of a primary HIV-1 infection initially induced by inoculating a mixture of three different virus strains, a chimpanzee was exposed to both immunostimulatory and immunosuppressive agents in an attempt to assess the contributions of different components of the immune system in suppressing circulating virus. The infusion of human leukocytes as an xenogeneic stimulus induced the replication of one of the input virus strains that had not previously been isolated or detected by PCR. The administration of high-dose, 17-day courses of corticosteroids resulted in coordinate and transient increases of each of the three viruses present in the original inoculum and elevation of HIV-1-specific ELISA antibody levels. Steroids administered to a second chimpanzee, chronically infected with a single HIV-1 isolate, also induced elevations of cell-associated virus. These results highlight the intimate relationship between immune system activation/immunosuppression and HIV replication in an animal model.