Study shows lower antibody cross-reactivity after infection with the B.1.1.7 SARS-CoV-2 difference

In a recent research paper available on the bioRxiv * preprint server, a diverse group of researchers has studied the immunogenicity of antibodies against the B.1.1.7 variant of true respiratory coronavirus syndrome 2 (SARS – CoV – 2) first detected in the UK United – and has shown reduced recognition and neutralization of either parental rays or vice versa South Africa.

The non-stop transmission of 2019 coronavirus infection (COVID-19) caused by SARS-CoV-2 continues to have a major impact on the health of people worldwide, as it can cause severe disease and affect health in the long run.

Recently, there has been an increase in rare public health incidents that may be due to modifications of SARS-CoV-2. For example, the World Health Organization (WHO) regularly monitors whether these viral changes are causing changes in transmission patterns, disease depth, or vaccine efficacy.

One notable variant of SARS-CoV-2 is the infamous B.1.1.7 strain, which was first discovered in the United Kingdom in September 2020 and has spread to more than fifty countries. since then. In South Africa, another variable appeared independently of B.1.1.7, and there is also a Brazilian version called P.1.

The problem is that mutations in the aforementioned variables may reduce recognition by antibodies derived from natural diseases with parental or primary sequences. That is why a large group of researchers, led by Dr. George Kassiotis of the Francis Crick Institute and Imperial College London investigated the degree of immunogenicity and heterotypic immunity that the new variants may provide.

Evaluating the barrier density of human sera

The sera for this study was collected from 29 patients who were admitted to London University College Hospital for unrelated reasons, but with a later confirmed B.1.1.7 infection. The majority (i.e., 79%) of these patients showed relatively mild COVID – 19 symptoms, and a smaller fraction of 21% remained asymptomatic.

To evaluate the potential for reduced antibody recognition and its functional outcome, the researchers have measured the semi-maximum inhibitory density (usually abbreviated as IC50) of D614G and B.1.1.7 sera, using Wuhan’s in vitro neutralization process, B.1.1. .7 (UK variable) and / or B.1.351 (South African variable) SARS-CoV-2 alone.

Overall, IgG, IgM and IgA antibodies to glycoprotein spike the Wuhan strain – but also of D614G modifications (this mutated version essentially replaced the first SARS-CoV-2 sequence that was released. detected in China), B.1.1.7 or B.1.351 – were expressed on a human HEK293T cell line and subsequently detected by a flow cytometry-based device.

Different cross-neutralization patterns

This study has shown that the infection with D614G caused a substantial and permanent overgrowth of the B.1.1.7 variant; however, the reverse was not true. In other words, the neutralization of Wuhan parental strain with B.1.1.7 sera was significantly reduced compared to the neutralization characteristics of the infectious variable B.1.1.7

Similar results were found independently in a recent study with a relatively small number of B.1.1.7 convalescent sera. Such a one-way pattern of cross-reactivity means that the potential culture for B.1.1.7 exposure was not the process known as ‘antibody escape’. ‘

Moreover, the difference in the cross-neutralization depression was statistically significant. Notably, both D614G and B.1.1.7 showed significantly lower neutralization sera of the B.1.351 variant with a complex variation of 8.8.2 and 7.7.7, respectively.

Identification of SARS – CoV – 2 specific spike glycoproteins by antibodies in D614G and B.1.1.7 sera. a – c, Correlation of IgG (a), IgM (b) and IgA (c) antibody levels to D614G and B.1.1.7 or B.1.351 spikes in the identified groups of donors with a second part with the D614G or B.1.1 .7 rays. Each symbol represents an individual sample and levels are expressed as a percentage of the positive control. Black lines indicate overall correlation and gray lines change 25% each side. d – f, Comparison of antibody levels of IgG (d), IgM (e) and IgA (f) to the spikes identified in groups of donors with severe infection with either the D614G or B sequences .1.1.7. Linked symbols represent individual donors. Numbers above the plots indicate the average connection to each spike, expressed as a percentage of contact with the infectious spike.

The era of multiple vaccines?

In summary, these findings suggest that natural infection with all strains of SARS-CoV-2 stimulates the formation of antibodies that identify the strongest infectious species, with varying degrees of over-identification of other series.

“While a quantitative correlation between in vitro neutralization of SARS – CoV – 2 infectious and in vivo protection from SARS-CoV-2 or severe COVID-19 infection remains to be explained, the reduced neutralization of SARS – CoV sequences – 2 others with B .1.1.7 sera would suggest that the recent wave of global B.1.1.7 diseases may not completely protect against re-infection with SARS-CoV – other 2 strains “, say study authors here bioRxiv paper.

The level of heterotypic immunity must be considered when selecting spike variants as vaccine candidates, with spike B.1.1.7 showing lower potential when compared directly to other variants. Finally, this antigenic difference associated with the evolution of SARS – CoV – 2 means that we can turn to the use of multivitamin vaccines.