Scientists, including Florian Klein, director of the Institute of Virology at the University Hospital of Cologne, have already compiled some findings on the new corona variant Omikron from South Africa and suspect that the new variant could have a higher infectivity, but probably causes milder courses of disease. However, the new mutant Omikron is already known as the „escape mutant“ or „immune escape“ because the immune response of vaccinated and recovered individuals could be weaker due to the mutations. Researchers will not know how pronounced the weakened antibody response may be for several weeks.
The recognition characteristics of a virus as a pathogen are altered in such a way that they could largely escape the immune system’s attack. The rapid aerosol spread also helps the viruses spread from person to person, host cell to host cell. Also, the mutations help in infecting the human host cells more easily.
The exact properties of the omicron variant now need to be analyzed in more detail in terms of dangerousness. However, the sequence of the genetic material in the virus suggests that there is cause for concern, the scientists already confirm: The type of the virus from Wuhan in China is altered at 50 positions in the genome compared to the new variant Omikron. Another cause for concern is the 30 mutations in the spike protein, which is the sting responsible for entry into human host cells. Antibodies usually neutralize spike proteins. The antibody proteins thus render the virus harmless. However, in the case of Omikron, the negative effects caused by changes in the sting are particularly dangerous.
Normally, the antibody-antigen (virus) reaction works like a lock-and-key model, so that antibodies render the virus harmless. Mutations of the amino acids in the genetic material of the viruses, by exchanging amino acids or losing sections of genetic material altogether, can give rise to dangerous virus variants such as Omikron.
In the case of Omikron, however, the exchange of the amino acid at position 484 of 1,300 amino acids in the code of the spike protein is particularly crucial because it alters the binding sites of the virus (lock-and-key-model). This ultimately means that the insensitivity to neutralizing antibodies already formed increases. However, there are also corresponding changes at other sites of the spike protein, which leads to the development of resistance, which in turn means that the existing antibodies then lose their effectiveness. However, data from the laboratory will provide clarity in the coming weeks on the extent to which Omikron can escape the grip of antibodies that have already been formed.
Source: www.zeit.de