A team of American scientists has discovered how the Delta and Kappa variants trick the antibody recognition system, thereby evading the immune response generated by vaccines.
Researchers from the University of Washington School of Medicine collected blood samples from 37 individuals aged 22 to 66. These individuals had received two full doses of either the Moderna or Pfizer-BioNTech vaccine, or a single dose of the Johnson & Johnson vaccine, according to India Times.
The analyzed data indicates that the Delta, Delta Plus, and Kappa variants significantly reduce the neutralizing efficacy of antibodies produced by vaccines.
The Delta Plus variant causes the most severe reduction in antibody efficacy. Antibodies in approximately 50% of individuals who received the Johnson & Johnson vaccine completely lose their effectiveness against these variants, the test results show.
Although the Kappa and Delta Plus variants exhibit a stronger resistance to vaccine-induced antibodies, Delta remains the dominant virus variant globally.
The Delta, Delta Plus, and Kappa variants can evade the immune system of vaccinated individuals. (Photo: AP).
The current vaccines primarily target the glycoprotein spikes on the surface of the SARS-CoV-2 virus. The glycoprotein spikes contain an N-terminal head that enhances the virus’s ability to attach to cells, along with a receptor-binding head that helps the virus bind to the ACE2 receptor on host cells.
Most antibodies generated by vaccines will attack specific sites on these two heads. Therefore, with variants that exhibit mutations in the N-terminal head and the receptor-binding head, as seen with Delta and Kappa, the antibodies become neutralized.
However, by closely examining the main infectious structures on these variants, scientists have identified a neutralizing antibody designated S2X303 that shows superior efficacy against the virus, with the ability to target multiple variants.
By understanding how this antibody interacts with the N-terminal head of the virus, scientists can determine how antibodies eliminate the virus.
The identification of antibodies capable of neutralizing multiple variants may assist scientists in developing new generation Covid-19 vaccines, creating a stronger and more effective immune response against various virus variants.
