Assessment of in vitro prophylactic and therapeutic efficacy of chloroquine against chikungunya virus in vero cells

• Published in: Journal of medical virology Vol. 82; no. 5; pp. 817 - 824
• Main Authors: Khan, Mohsin, Santhosh, S.R, Tiwari, Mugdha, Lakshmana Rao, P.V, Parida, Manmohan
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.05.2010; Wiley
• Subjects: Animals; Antiviral Agents - pharmacology; Biological and medical sciences; Cell Survival; Chikungunya; Chikungunya virus - drug effects; Chlorocebus aethiops; chloroquine; Chloroquine - pharmacology; Fundamental and applied biological sciences. Psychology; Human viral diseases; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; Reverse Transcriptase Polymerase Chain Reaction; RNA, Viral - biosynthesis; Vero Cells; Viral diseases; Viral Plaque Assay; Virology; virus inhibition; Virus Internalization - drug effects; Virus Replication - drug effects; Antimalarial; Chloroquine; Togaviridae; virus inhibition; In vitro; Infection; Virus; Prevention; Efficiency; Viral disease; Arbovirus disease; Chikungunya virus; Chikungunya; Alphavirus; Parasiticide; Antirheumatic agent
• ISSN: 0146-6615; 1096-9071; 1096-9071
• DOI: 10.1002/jmv.21663

The resurgence of Chikungunya virus (CHIKV) in the form of unprecedented and explosive epidemics in India and the Indian Ocean islands after a gap of 32 years is a major public health concern. Currently, there is no specific therapy available to treat CHIKV infection. In the present study, the in vitro prophylactic and therapeutic effects of chloroquine on CHIKV replication in Vero cells were investigated. Inhibitory effects were observed when chloroquine was administered pre-infection, post-infection, and concurrent with infection, suggesting that chloroquine has prophylactic and therapeutic potential. The inhibitory effects were confirmed by performing a plaque reduction neutralization test (PRNT), real-time reverse transcriptase (RT)-PCR analysis of viral RNA levels, and cell viability assays. Chloroquine diminished CHIKV infection in a dose-dependent manner, with an effective concentration range of 5-20 μM. Concurrent addition of drug with virus, or treatment of cells prior to infection drastically reduced virus infectivity and viral genome copy number by ≥99.99%. The maximum inhibitory effect of chloroquine was observed within 1-3 hr post-infection (hpi), and treatment was ineffective once the virus successfully passed through the early stages of infection. The mechanism of inhibition of virus activity by chloroquine involved impaired endosomal-mediated virus entry during early stages of virus replication, most likely through the prevention of endocytosis and/or endosomal acidification, based on a comparative evaluation using ammonium chloride, a known lysosomotropic agent. J. Med. Virol. 82: 817-824, 2010.