Therapeutic effect of (5R)-5-hydroxytriptolide (LLDT-8) in SIV infected rhesus monkeys

Human immunodeficiency virus (HIV) infections induce robust, generalized inflammatory responses and lead to pathological systemic immune activation. This abnormal immune status persists despite successful antiretroviral therapy (ART). Immune modulating strategies in conjunction with ART were tried to reduce abnormal immune activation. Previously, we demonstrated that Tripterygium Wilfordii Hook F has been shown immunosuppressive activity in HIV patients. (5R)-5-hydroxytriptolide (LLDT-8), a new analog of triptolide, and the most active ingredient of Tripterygium Wilfordii Hook F, has been shown to have lower cytotoxicity. However, the role of LLDT-8 in HIV or simian immunodeficiency virus (SIV) needs to be explored.

Six male adult Chinese rhesus monkeys were enrolled in our study. All of them were healthy and negative for SIV, and chronically SIVmac239 infected macaques were treated with LLDT-8 combined with ART (n = 4) or ART only (n = 2) after 14 weeks of infection. ART was determined at week 33, and LLDT-8 was continued until week 48. T cell immune activation and inflammation were compared during the period, and viral rebound time and reservoir were supervised after stopping ART.

The RNA level of the two groups continued to decline after initiating ART, RNA of 4 rhesus monkeys declined to the lower limit of detection at week 20. LLDT-8 administration combined with ART did not affect T cell activation and plasma levels of IL-6 and CRP. The viral load of all the macaques in both groups was rebounded 2 weeks after ART discontinuation. Furthermore, no significant decrease of SIV DNA was observed in the LLDT-8 treatment group.

LLDT-8 administration during chronic SIV infection had no effect on T cell activation and plasma levels; Furthermore, LLDT-8 may not contribute to suppression of viral rebound and reservoir. These results suggest that LLDT-8 is unlikely to reduce immune activation and viral persistence without additional interventions.