Weak Cross-Lineage Neutralization by Anti SARS-CoV-2 Spike Antibodies after Natural Infection or Vaccination Is Rescued by Repeated Immunological Stimulation

• Published in: Vaccines (Basel) Vol. 9; no. 10; p. 1124
• Main Authors: Caucci, Sara, Corvaro, Benedetta, Tiano, Sofia Maria Luigia, Valenza, Anna, Longo, Roberta, Marinelli, Katia, Ferreri, Monica Lucia, Spiridigliozzi, Patrik, Salvoni, Giovanna, Bagnarelli, Patrizia, Menzo, Stefano
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.10.2021; MDPI
• Subjects: Amino acids; anamnestic response; Antibodies; Antibody response; Automation; BAU; Coronaviruses; COVID; COVID-19; COVID-19 vaccines; Divergence; Evolution; Herd immunity; Immune response; Immunology; Infections; Infectious diseases; Medical personnel; Mutation; Neutralization; Neutralizing; neutralizing antibodies; SARS; Severe acute respiratory syndrome coronavirus 2; Vaccination; vaccine; Vaccine efficacy; Vaccines; Viruses; United States > US; Italy; COVID; vaccine; anamnestic response; vaccine dose; BAU; SARS; neutralizing antibodies
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines9101124

After over one year of evolution, through billions of infections in humans, SARS-CoV-2 has evolved into a score of slightly divergent lineages. A few different amino acids in the spike proteins of these lineages can hamper both natural immunity against reinfection, and vaccine efficacy. In this study, the in vitro neutralizing potency of sera from convalescent COVID-19 patients and vaccinated subjects was analyzed against six different SARS-CoV-2 lineages, including the latest B.1.617.2 (or Delta variant), in order to assess the cross-neutralization by anti-spike antibodies. After both single dose vaccination, or natural infection, the neutralizing activity was low and fully effective only against the original lineage, while a double dose or a single dose of vaccine, even one year after natural infection, boosted the cross-neutralizing activity against different lineages. Neither binding, nor the neutralizing activity of sera after vaccination, could predict vaccine failure, underlining the need for additional immunological markers. This study points at the importance of the anamnestic response and repeated vaccine stimulations to elicit a reasonable cross-lineage neutralizing antibody response.