Cytokine enhancement of simian immunodeficiency virus (SIV/mac) from a chronically infected cloned T-cell line (HuT-78).

Simian immunodeficiency viruses (SIV) are a family of primate lentiviruses similar to human immunodeficiency viruses (HIV) in their genetic sequence and pathogenesis. However, host-derived cofactors which may determine the extent of viral replication are not clearly defined for SIV or HIV infections. A HuT-78 cell line chronically infected with SIV/mac strain 251, was biologically cloned and characterized for the ability to produce infectious viral particles, viral structural protein profile, cellular antigen surface phenotype and tested to determine the effects of recombinant cytokines on SIV replication. Reverse transcriptase (RT) assay was used to measure the replication of SIV/mac in response to various concentrations of recombinant cytokines (1-1000 units/ml). We report that tumor necrosis factor-alpha (rTNF-alpha), gamma-interferon (rIFN-gamma), interleukin 2 (rIL-2), and granulocyte-macrophage colony stimulating factor (rGM-CSF) induced approximately a 2 to 3 fold increase in virus RT activity compared with untreated SIV-infected HuT-78 cells. In contrast, viral replication was not enhanced or minimally enhanced by interleukin 1 (rIL-1), interleukin 3 (rIL-3), or interleukin 4 (rIL-4) at similar dosages. Furthermore, SIV replication in response to rTNF-alpha and rIFN-gamma occurred in a dose dependent fashion. These data suggest that SIV-infected T-lymphocyte lines are responsive to particular cytokines resulting in increased virus production.