Natural SARS-CoV-2 Infection Affects Neutralizing Activity in Saliva of Vaccinees

Frontiers in Immunology

Andrea Introini¹  Mario Clerici²  Olga Utyro³  Sergio Strizzi³  Mara Biasin³  Micaela Garziano⁴  Irma Saulle⁴  Sergio Lo Caputo⁵  Mariacristina Poliseno⁵  Teresa Antonia Santantonio⁵ 

[1] Center for Molecular Medicine, Department of Medicine Solna, Division of Infectious Diseases, Karolinska University Hospital, Karolinska Institutet, Solna, Sweden;Don C. Gnocchi Foundation, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation, Milan, Italy;Laboratory of Immunobiology, Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Milan, Italy;Laboratory of Immunology, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy;Unit of Infectious Diseases, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy;

关键词: SARS-CoV-2;    saliva;    neutralizing activity;    antibodies;    variants;   

DOI  :  10.3389/fimmu.2022.820250

来源: DOAJ

【 摘 要 】

BackgroundSARS-CoV-2 transmission mainly occurs through exposure of the upper airway mucosa to infected secretions such as saliva, which are excreted by an infected person. Thus, oral mucosal immunity plays a central role in the prevention of and early defense against SARS-CoV-2 infection. Although virus-specific antibody response has been extensively investigated in blood samples of SARS-CoV-2-infected patients and vaccinees, local humoral immunity in the oral cavity and its relationship to systemic antibody levels needs to be further addressed.Material and MethodsWe fine-tuned a virus neutralization assay (vNTA) to measure the neutralizing activity (NA) of plasma and saliva samples from 20 SARS-CoV-2-infected (SI), 40 SARS-CoV-2-vaccinated (SV), and 28 SARS-CoV-2-vaccinated subjects with a history of infection (SIV) using the “wild type” SARS-CoV-2 lineage B.1 (EU) and the Delta (B.1.617.2) strains. To validate the vNTA results, the presence of neutralizing antibodies (NAbs) to the spike receptor binding domain (RBD) was evaluated with an ELISA assay.ResultsNA to SARS-CoV-2 lineage B.1 (EU) was present in plasma samples from all the tested subjects, with higher titers in SIV compared to both SI and SV. Conversely, NA was detected in saliva samples from 10.3% SV, 45% SI, and 92.6% SIV, with significantly lower titers in SV compared to both SI and SIV. The detection of NAbs in saliva reflected its reduced NA in SV.DiscussionThe difference in NA of plasma vs. saliva was confirmed in a vNTA where the SARS-CoV-2 B.1 and Delta strains were tested head-to-head, which also revealed a reduced NA of both specimens compared to the B.1 variant.ConclusionsThe administration of SARS-CoV-2 vaccines was associated with limited virus NA in the oral cavity, as measured in saliva and in comparison to plasma. This difference was more evident in vaccinees without a history of SARS-CoV-2 infection, possibly highlighting the importance of local exposure at the site of virus acquisition to effectively prevent the infection and block its spread. Nevertheless, the presence of immune escape mutations as possibly represented by the SARS-CoV-2 Delta variant negatively affects both local and systemic efficacy of NA associated with vaccination.

【 授权许可】

Unknown