Explained: How Delta, Kappa variants of Covid-19 evade immune system

A team of US scientists have explored how the mutations in Delta and Kappa variants of the Covid virus help the variants avoid recognition by antibodiesThe scientists from the University of Washington School of Medicine obtained plasma samples from 37 individuals ranging in age from 22 to 66 who had received either two doses of the Moderna or PfizerBioNtech or one dose of the Janssen Covid19 vaccinesTheir data demonstrated that the Delta Kappa and Delta Plus variants reduced virus neutralising potency from vaccineinduced antibodiesThe Delta Plus variant caused the greatest decrease Antibodies from half of the Janssenvaccinated individuals completely lost the ability to neutralise one or more variants in the laboratory assayAlthough the Kappa and Delta Plus variants were better able to evade vaccineelicited antibody neutralisation it was the Delta variant that became dominant worldwideVaccine developers have largely concentrated on targeting the spike glycoprotein on the surface of the Covid virus The spike glycoprotein includes an Nterminal domain that enhances cell binding and a receptor binding domain that engages with the ACE2 receptor on host cellsMost antibodies against the pandemic coronavirus latch onto specific sites on these two domains Consequently coronavirus variants have mutated their Nterminal domain and receptor binding domain to evade these antibodies as is the case for the delta and kappa variants the team saidThese are the major targets of neutralising antibodies in convalescent and vaccinated individuals thereby raising concerns about the efficacy of available vaccines and therapeutic antibodies against these Kappa and Delta variants the researchers wrote in the paper published in the journal ScienceClosely examining the structures of the main infectivity structure in the variant coronaviruses one antibody called S2X303 stood out because of its skill in crossreacting with several variants compared to all other neutralising antibodiesBy exploring how this antibody is bound to the Nterminal domain the scientists got a clearer picture of how it attacks its target This antibody takes an unusual angle of approach to make a unique contact footprint within the Nterminal domainThe discovery of broadly neutralising coronavirus antibodies is also informing new Covid19 vaccine ideas and also helping scientists to work on nextgeneration vaccine candidates that might be able to produce broad immunity against sarbecovirusesThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever