Page 19 - NIH Bulletin Vol. 17 July 2021 #WeMustWin

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SUCCESSFUL ISOLATION AND

PROPAGATION OF MALAYSIAN

SARS-COV-2 STRAIN

MAMMALIAN CELL LINES

A novel coronavirus (nCoV) has been responsible
for the recent pneumonia outbreak that started in
early December 2019 in the city of Wuhan, Hubei
Province, China. The virus was identified as SARS-
CoV-2 while the disease is called Coronavirus
Disease 2019 (COVID-19). Following that, many
studies were carried out on COVID-19 with emphasis
on the detection and treatment of the disease.
Isolation and propagation of the pathogens from
the patients was one of the important steps to
provide capacity for all related studies.

Following confirmation by real-time RT-PCR Figure 1: Cytopathic effect (CPE) image of SARS-CoV-2-inoculated Vero E6 cell
during the routine diagnostic test for COVID-19 in line. Image was taken at 100x magnification.
the Institute for Medical Research (IMR), virus from
the clinical sample was isolated and propagated
in several selected mammalian cell lines in the
Biosafety Level 3 laboratory (BSL-3).

Through Whole Genome Sequencing (WGS), the
strains that have been circulated among Malaysian
population were characterized to be of (i) Type
B derived, (ii) B ancestral, and (iii) C derived. We
attempted to propagate all of these strains in
the mammalian cell lines of choice. Given the
preference of the virus towards respiratory cells,
the selected mammalian cell lines in this study are
mostly of respiratory lineage origin.
Figure 2: Representative electron micrograph of SARS-CoV-2
Evaluation on the capacity of the cells to propagate in Vero E6 cell lines.
each of the virus isolates used in the study will
be performed by recording the cytopathic effect
(CPE), growth kinetics, and virus morphology
through transmission electron microscopy (EM).
In addition to that, the yield in the form of viral
copy numbers at the end of the propagation will
be determined by real-time RT-PCR. Furthermore,
the impact of different hosts on genetic stability of
these viruses will be analysed by WGS at the end of
the experiment.

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