[Effects of chloroquine on the replication of a murine retrovirus]

The wide use of chloroquine (Cq) for prophylaxis and chemotherapy of malaria in Africa, and the increased spread of AIDS in areas of this continent where malaria is endemic, raised the question of a possible interaction between chloroquine intake and HIV infection. Indeed, hydroxychloroquine and chloroquine itself have been shown to inhibit HIV-1 replication in vitro, hydroxychloroquine being proposed as a potential useful adjunctive therapy in the treatment of HIV-1 infection. On the other hand, chloroquine has been reported to enhance the replication of Semliki forest and encephalomyocarditis viruses in a mouse model. In an attempt to elucidate Cq effect on retroviral replication, we have studied the effect of various concentrations of chloroquine in vitro (0.1 nmol/l to 25 mumol/l) on Friend retrovirus (FV)-infected fibroblasts of mice and in vivo (2 to 30 mg/kg) on FV-infected mice. No reduction in the number of virus foci was found in chloroquine-treated fibroblasts cultures. In chloroquine treated-infected mice, no differences were observed in the spleen weights, except an increase at 10 mg/kg. A decrease in splenocyte virus titer was only observed at 10 and 30 mg/kg. No differences in the median survival time was observed up to 30 mg/kg. The authors concluded that chloroquine seemed to have variable effects on viral replication in vivo depending on the dosage, but has no influence on the course of FV-induced disease.