Chloroquine interferes with the virus's ability to replicate in two ways. First, the drug enters compartments called endosomes within the cell membrane. Endosomes tend to be slightly acidic, but the chemical structure of the drug boosts their pH, making the compartments more basic. Many viruses, including SARS-CoV, acidify endosomes in order to breach the cell membrane, release their genetic material and begin replication; chloroquine blocks this critical step.
The drug also prevents SARS-CoV from plugging into a receptor called ACE2, on primate cells, according to the 2005 report. When the virus inserts its spike protein into the ACE2 receptor, it sets off a chemical process that alters the structure of the receptor and allows the virus to infect. An adequate dose of chloroquine appears to undermine this process, and in turn, viral replication in general, the authors noted.
"It was thought that whatever pertained to SAR-CoV-1 might apply to SARS-CoV-2," Horovitz said.
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By Nicoletta Lanese - Staff Writer
