- Izumi Kimura showed that Lambda spike (S) is highly infectious and T76I and L452Q are responsible for this property.
- Lambda S is more susceptible to an infection-enhancing antibody.
- RSYLTPGD246-253N, L452Q and F490S confer resistance to antiviral immunity.
The SARS-CoV-2 Lambda BS variant, also known as lineage C.37, is a variant of SARS-CoV-2, the virus that causes COVID-19. It was first detected in Peru in December 2020. On 14 June 2021, the World Health Organization named it Lambda variant and designated it as a variant of interest. Although the vaccination rate in Chile is relatively high (i.e. 60% people received at least one dose), a big Covid-19 surge has occurred in Chile in Spring 2021, which suggested that the Lambda variant is proficient in escaping from the antiviral immunity elicited by vaccination. Besides, that its virological features and evolutionary trait remain unknown.
Now, Izumi Kimura and colleagues revealed the virological features and evolutionary trait of the Lambda variant by performing virological experiments and molecular phylogenetic analysis.
They demonstrated that, there are three mutations which confer resistance to the vaccine-induced antiviral immunity, those are RSYLTPGD246-253N, L452Q and F490S mutations, respectively. Additionally, the T76I and L452Q mutations contributed to enhanced viral infectivity.
“Our data suggest that there are at least two virological features on the Lambda variant: increasing viral infectivity (by the T76I and L452Q mutations) and exhibiting resistance to antiviral immunity (by the RSYLTPGD246-253N, L452Q and F490S mutations).”— they wrote.
They also demonstrated that the RSYLTPGD246-253N mutation, a unique mutation in the NTD of the Lambda Spike protein, is responsible not only for the resistance to the vaccine-induced neutralization as well as an NTD-targeting NAb, but also for the virological phenotype of the Lambda variant that can associate with the massive infection spread mainly in South American countries.
“Because the Lambda variant is a VOI, it might be considered that this variant is not an ongoing threat compared to the pandemic VOCs. However, because the Lambda variant is relatively resistant to the vaccine-induced antisera, it might be possible that this variant is feasible to cause breakthrough infection.”— they said.
More studies on the evolutionary traits and virological features of SARS-CoV-2 variants are required in order to explain the possibility of wider spread of epidemic and for assessing the risk of future emerging SARS-CoV-2 variants.
Featured image: Graphical abstract © authors
Reference: Izumi Kimura, Yusuke Kosugi, Jiaqi Wu, Daichi Yamasoba, Erika P Butlertanaka, Yuri L Tanaka, Yafei Liu, Kotaro Shirakawa, Yasuhiro Kazuma, Ryosuke Nomura, Yoshihito Horisawa, Kenzo Tokunaga, Akifumi Takaori-Kondo, Hisashi Arase, The Genotype to Phenotype Japan (G2P-Japan) Consortium, Akatsuki Saito, So Nakagawa, Kei Sato, “SARS-CoV-2 Lambda variant exhibits higher infectivity and immune resistance”, bioRxiv 2021.07.28.454085; doi: https://doi.org/10.1101/2021.07.28.454085
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