免疫学：回復期患者におけるSARS-CoV-2の交差中和抗体応答

Convalescent COVID-19 patients maintain a robust neutralizing antibody response after recovery, which, in some cases includes antibodies that can neutralize other coronaviruses, finds a paper published in Nature Microbiology. This case study improves our understanding of the immune response to SARS-CoV-2 and has implications for the treatment of the infection and for vaccine development.

Neutralizing antibodies, which are made by white blood cells called B cells, help to defend the body from invading pathogens by neutralizing their biological activity. However, little is known about the neutralizing antibodies that form in response to SARS-CoV-2 infection.

Xiaowang Qu and colleagues analysed the sera from 67 patients who were convalescing from COVID-19 in Hunan, China, and found that the majority of the patients maintained levels of neutralizing antibodies one month after leaving the hospital, and that some of the sera could cross-neutralize SARS-CoV and MERS-CoV. They found stronger neutralizing antibody responses in patients who had recovered from severe COVID-19. This response was associated with higher frequency of circulating immune cells called T follicular helper (TFH) cells, which help B cells to produce antibodies, compared to individuals who recovered from non-severe COVID-19.

The authors conclude that TFH cells may have a role in the initiation or maintenance of the neutralizing antibody responses. Furthermore, the cross-reactivity of SARS-CoV-2 neutralizing antibodies to other coronaviruses suggests that it may be possible to design a pan-coronavirus vaccine that protects against multiple coronaviruses.