CSIR-CCMB initiates Coronavirus cell culture to potentially make vaccines, test drugs

The CSIR-Centre for Cellular and Molecular Biology (CCMB) has established stable cultures of Covid-19 causing Coronavirus, SARS-CoV-2 from patients’ samples over the last month and a half.

A team of researchers led by CCMB virologist Krishnan H Harshan has isolated infectious viruses from several isolates. The ability to culture the virus in a lab enables CCMB to work towards vaccine development and testing potential drugs to fight Covid-19. It also makes them a potential donor of the culture to other authorised centres that can continue growing the virus for their own use.

This virus is known to infect epithelial cells in the human respiratory tract. The virus infects these cells by interacting with the receptor proteins called ACE-2 following which the virus is internalised by a process namely endocytosis. Virus RNA is later released into the cytoplasm of the cells where it makes viral proteins first and then starts to replicate the genomic RNA. Thus, the virus uses resources from these cells to make more copies of itself. Therefore, the virus needs a set of host factors that allow it to replicate.

“Currently, primary epithelial cells generated from human origins do not grow for many generations in labs, which is key to culturing the viruses continuously. And hence, CCMB and other labs that are growing the virus needs an ‘immortal’ cell line,” Krishnan said.

They use Vero cells ― kidney epithelial cell lines from the green African monkey, which express ACE-2 proteins and carry a mutation that allows them to proliferate indefinitely.

CCMB Director Rakesh Mishra, in a statement said, “Using the Vero cell lines to grow the coronavirus, CCMB is now in a position to isolate and maintain viral strains from different regions. We are working towards producing viruses in huge quantities that can be inactivated, and used in vaccine development and antibody production for therapeutic purposes.”

“We have also started testing potential drugs with other partners, such as DRDO, using this viral culture. We hope that such systems are replicated at multiple research institutes and private companies to become a useful resource in the fight against this pandemic as well as for future preparedness,” Mishra said.

Potential uses of cultured SARS-CoV-2 include development of vaccine, antibodies or anti-dotes, testing of antibodies, drug-screening, testing of various disinfectants and testing of instruments.

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