Which SARS-CoV-2 spike mutants can evade T cell immunity?

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fairly difficult
A new study reports the capability of a new variant of the virus to escape specific cellular immunity, while possessing a higher binding affinity to the host cell binding receptor, the angiotensin-converting enzyme 2 (ACE2).
Caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus disease 2019 (COVID-19) pandemic continues to pose challenges to public health and economic well-being worldwide. To date, over 132.5 million cases of COVID-19 and over 2.8 million deaths have been confirmed.

A characteristic of this pandemic has been the emergence of numerous viral variants, some of which have spread rapidly to become the dominant strain. One such early variant was the D614G strain which then became the globally dominant lineage.

A new study, released on the bioRxiv* preprint server, reports the capability of a new variant of the virus to escape specific cellular immunity, while possessing a higher binding affinity to the host cell binding receptor, the angiotensin-converting enzyme 2 (ACE2).

Circulating variants

The D614G mutation markedly increased the viral binding affinity to the receptor, boosting infectivity and viral fitness, and thus enhancing its transmissibility. Much more recently, three variants of concern arose, termed the UK, South African and Brazil variants (B.1.1.7, also known as VOC 202012/01 or 20I/501Y.V1; B.1.351 (also known as 20H/501Y.V2); and P.1 (also known as 501Y.V3).

At the close of 2020, yet another variant has been circulating at a dominant level in California, USA, termed B.1.427/429 (also 111 known as CAL.20C). Cross-species transmission of the virus to mink was associated with the emergence of SARS-CoV-2 variant B.1.298.

Thus, genomic surveillance of circulating virus strains is essential to capture the effects of mutations on viral infectivity, virulence and immune resistance.

Unlike the UK variant, the B.1.351 and P.1 variants show moderate resistance to neutralization by antibodies specifically targeting the wildtype virus.

Cellular virus-specific immunity

The current study explores the resistance offered by new variants to HLA-restricted cellular immunity mediated by cytotoxic T lymphocytes (CTLs).

These cells…
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