Reduced sensitivity of the SARS-CoV-2 Lambda variant to monoclonal antibodies and neutralizing antibodies induced by infection and vaccination

Severe acute respiratory syndrome coronavirus 2 variants have continued to emerge in diverse geographic locations with a temporal distribution. The Lambda variant containing multiple mutations in the spike protein, has thus far appeared mainly in South America. The variant harbours two mutations in the receptor binding domain, L452Q and F490S, which may change its infectivity and antigenicity to neutralizing antibodies. In this study, we constructed 10 pseudoviruses to study the Lambda variant and each individual amino acid mutation's effect on viral function, and used eight cell lines to study variant infectivity. In total, 12 monoclonal antibodies, 14 convalescent sera, and 23 immunized sera induced by mRNA vaccines, inactivated vaccine, and adenovirus type 5 vector vaccine were used to study the antigenicity of the Lambda variant. We found that compared with the D614G reference strain, Lambda demonstrated enhanced infectivity of Calu-3 and LLC-MK2 cells by 3.3-fold and 1.6-fold, respectively. Notably, the sensitivity of the Lambda variant to 5 of 12 neutralizing monoclonal antibodies, 9G11, AM180, R126, X593, and AbG3, was substantially diminished. Furthermore, convalescent- and vaccine-immunized sera showed on average 1.3-2.5-fold lower neutralizing titres against the Lambda variant. Single mutation analysis revealed that this reduction in neutralization was caused by L452Q and F490S mutations. Collectively, the reduced neutralization ability of the Lambda variant suggests that the efficacy of monoclonal antibodies and vaccines may be compromised during the current pandemic.

The SARS-CoV-2 Lambda variant exhibits enhanced infectivity and immune resistance

SARS-CoV-2 Lambda, a variant of interest, has spread in some South American countries; however, its virological features and evolutionary traits remain unclear. In this study, we use pseudoviruses and reveal that the spike protein of the Lambda variant is more infectious than that of other variants due to the T76I and L452Q mutations. The RSYLTPGD246-253N mutation, a unique 7-amino acid deletion in the N-terminal domain of the Lambda spike protein, is responsible for evasion from neutralizing antibodies and further augments antibody-mediated enhancement of infection. Although this mutation generates a nascent N-linked glycosylation site, the additional N-linked glycan is dispensable for the virological property conferred by this mutation. Since the Lambda variant has dominantly spread according to the increasing frequency of the isolates harboring the RSYLTPGD246-253N mutation, our data suggest that the RSYLTPGD246-253N mutation is closely associated with the substantial spread of the Lambda variant in South America.

Multiple Introductions of SARS-CoV-2 C.37 Lambda lineage in the Southern Brazilian region

Deemed a variant of concern by the World Health Organization on June 15^th, the Lambda variant of SARS-CoV-2 is a growing epidemiological threat in several South American countries, and initial results suggest it exhibits increased infectivity and immune escape qualities. Here, we present evidence of its multiple introductions in Brazil.

The Emergence of Sars-CoV-2 Variant Lambda (C.37) in South America

We report the emergence of a novel lineage of SARS-CoV-2 in South America, termed C.37. It presents seven nonsynonymous mutations in the Spike gene (Δ247-253, G75V, T76I, L452Q, F490S, T859N) and a deletion in the ORF1a gene (Δ3675-3677) also found in variants of concern (VOCs) Alpha, Beta, and Gamma. Initially reported in Lima, Peru, in late December 2020, it now accounts for 97% of Peruvian public genomes in April 2021. It is expanding in Chile and Argentina, and there is evidence of onward transmission in Colombia, Ecuador, Mexico, the USA, Germany, and Israel. On June 15, 2021, the World Health Organization designated C.37 as Variant of Interest (VOI) Lambda.

SARS-CoV-2 Lambda (C.37): An emerging variant of concern?

Many SARS-CoV-2 variants have high infectivity and transmissibility. The viral genome data show that the COVID-19 curves of daily case numbers were shaped by the emergence of the variants, including Alpha 202012/01 GRY (B.1.1.7; the U.K.), Beta GH/501Y.V2 (B.1.351, B.1.351.2, and B.1.351.3; South Africa), Gamma GR/501Y.V3 (P.1, P.1.1, and P.1.2; Japan, Brazil), Eta G/484K.V3 (B.1.525; Nigeria, the U.K.), Delta G/478K.V1 (B.1.617.2, AY.1, AY.2, and AY.3; India), Iota GH/253G.V1 (B.1.526; the U.S.A.), and Kappa G/452R.V3 (B.1.617.1; India). The Lambda (C.37) variant was reported in Peru initially; this has spread to 41 countries in four continents. Seven out of eight mutations in this variant are associated with the viral spike protein, akin to mutations in the other variants. These mutations have implications for effectiveness of the vaccines and neutralizing antibodies in immunized subjects and those previously infected with the virus and are thought to facilitate the viral invasion into host cells and help the virus evade the host immune system. Widespread dissemination of the viral variants may cause severe clinical consequences, lengthy hospitalizations, and unfavorable prognoses. Healthcare systems will be stretched, and health workers will be fatigued. Fast, equitable, and widespread vaccination with strict adherence to hygiene protocols will control the rising curves of the pandemic due to the new variants.