Use of herpesvirus saimiri-immortalized macaque CD4(+) T cell clones as stimulators and targets for assessment of CTL responses in macaque/AIDS models

Herpesvirus saimiri (HVS), a nonhuman primate γ herpes virus, was used to immortalize pig-tailed macaque CD4⁺ T lymphocytes. The HVS-immortalized T cell lines were used to develop CD4⁺ T cell clones from two animals. Three CD4⁺ T cell clones were further characterized for the expression of cell surface markers. All expressed CD2, CD4, CD58, CD69 and CD80 and therefore resembled activated T cells. These clones required exogenous IL-2 for efficient growth and were found to be highly susceptible to infection by the challenge virus, Chimeric simian/human immunodeficiency virus (SHIV_KU-1). They could also be productively infected not only by the quasispecies of the challenge virus (SHIV_KU-1/PDJ and SHIV_KU-1/PNA, isolated from macaque PDj and PNa, respectively) but also by a different chimeric simian/human immunodeficiency virus (SHIV_89.6P) and simian immunodeficiency virus (SIV_MAC239). The virus-infected CD4⁺ T cell clones were also used as stimulators for generation of CTL effectors. These effectors exhibited excellent virus-specific lysis in chromium-release assays when syngenic SHIV_KU-1 infected autologous CD4⁺ T cell clones were used as targets. The target cell lysis was virus specific, as uninfected control cells showed no or minimal lysis.