What are neutralizing antibodies?

The immune response to an infection becomes more effective after one to two weeks, when specific antibodies against the SARS-CoV-2 coronavirus are produced by the body. In a study of 160 cases with minor forms of SARS-CoV-2 COVID-19 among hospital staff in Strasbourg, it was shown that 99% of the people were found to be carrying specific antibodies against the SARS-CoV-2 virus 2-3 weeks after the onset of symptoms. After 4 weeks, the efficacy of these antibodies to neutralise the SARS-CoV-2 virus was detected in 98% of cases, in cell culture. These initial results suggest immune protection after infection with the SARS-CoV-2 virus and need to be validated by further studies. For patients infected with another SARS-CoV-1 coronavirus, antibodies are still present 2 years after the onset of SARS symptoms. The persistence of antibodies, and the duration of immune protection, remains to be determined in the case of SARS-CoV-2 infection.

Researchers are analyzing the blood composition of patients who have recovered from the diseaseCOVID-19, to characterize the antibodies and understand how they have won the part against the virus, and thus understand what the Achilles heel of CoV-2 SARS is. In addition, antibodies directed against the SARS-CoV-2 virus, or its ACE2 receptor present on the surface of infected cells, have been synthesized in the laboratory and will be tested to determine their effectiveness in neutralizing the SARS-CoV-2 virus. Another therapeutic strategy being tested involves transfusing plasma from COVID-19 cured patients to patients with severe SARS-CoV-2 infection. By providing antibodies to the SARS-CoV-2 virus, it is hoped that this transfusion could prevent further disease COVID-19 progression in the most severely affected patients. In some viral infections, such as Dengue fever, antibody levels have been shown to be an important parameter. At certain doses, antibodies can have a perverse effect, making the infection easier rather than fighting it. Thus, the mode of action of antibodies to the SARS-CoV-2 virus must be studied in detail before it can be used as therapy.