A team of experts in Germany has found that a variant of the SARS-CoV-2 virus that has been found in India for the first time, might be slightly more effective in infecting certain types of lung and intestine cells as compared to the original strain of the virus. The Indian variant of the virus is known as the B.1.617 strain. This variant belongs to the lineage that has been responsible for a sharp rise in the number of COVID19 cases and deaths in India in the past few weeks. The study has been done by experts from the German Primate Center in Gottingen, the University of Gottingen Medical Center, the Friedrich-Alexander University of Erlangen-Nurnberg, and Hannover Medical School. Scientists have said that the infection of the B.1.617 variant has been treated with soluble angiotensin-converting enzyme 2 (ACE2) or the serine protease inhibitor Camostat. However, the host entry of the variant has not been prevented with the monoclonal antibody therapy called Bamlanivimab. It has been given approval for emergency use for COVID19 treatment. Experts have said that the variant has been able to dodge antibodies developed after past infection or vaccination with the Pfizer-BioNTech and Moderna shots. The study is being peer-reviewed by experts at present.
The lead author of the study, Markus Hoffman, and his teammates have warned that the variant’s ability to dodge the antibodies might lead to further spread of this deadly strain. Since the COVID19 pandemic has started in 2019, various concerning variants of the SARS-CoV-2 virus have emerged across the world. Experts have said these strains might derail the efforts to end the pandemic. The strain called B.1.1.7 that has been found in the UK has spread across many nations. It has been proved to be more contagious as compared to other circulating strains. It has led to surging cases in many communities as well. Experts have said that higher infectivity might be linked to the N501Y mutation in the receptor-binding domain (RBD) of the spike protein of the virus. The spike protein helps the virus to infect host cells, said the experts. As per the experts, the spike protein is made of two subunits. The RBD present in subunit 1 attaches to the ACE2 receptor of the host cell. It is followed by the launch of the spike protein via transmembrane protease serine 2 (TMPRSS2). Subunit 2 helps the blend of the virus and cell membrane to activate the delivery of the viral genome into the cell. These courses are crucial for the SARS-CoV-2 virus. Health experts have said that the monoclonal antibody therapies primarily target the spike protein of the virus. Neutralizing antibodies that are developed after vaccination and initial infection as well attack the spike protein of the virus. Other variants of the virus such as the B.1.351 and P.1 that have emerged in South Africa and Brazil respectively contain the spike RBD mutation that is known as E484K. This mutation as well can dodge the effects of neutralizing antibodies. Experts have said that antibody evasion has seen the most in the B.1.351 strain. They have said that it is uncertain whether or not some strains might come up that will have full resistance to antibodies.
India has been reporting a sharp rise in the number of COVID19 cases in recent weeks. Health experts have said that these cases are caused by the deadly B.1.617 strain that contains eight mutations in the spike protein. The variant includes L452R and E484Q RBD mutations as well that can alter antibody-triggered neutralization. It is unclear whether or not these mutations will alter the virus’s susceptibility to drugs, said the experts. Experts have infected eight cell lines with pseudo-typed virus particles of B.1.617 strain and B.1.351. They have found that the B.1.617 strain and B.1.351 strains have been able to enter in the Calu-3 lung cells and Caco-2 colon cells with little more efficiency. Experts have said that the B.1.617 spike derived entry in the host cell can be subdued by soluble ACE2 that targets RBD.
