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SARS-CoV-2 vaccination elicits unconventional IgM specific responses in naïve and previously COVID-19-infected individuals

Ruggiero, Alessandra, Piubelli, Chiara, Calciano, Lucia, Accordini, Simone, Valenti, Maria Teresa, Carbonare, Luca Dalle, Siracusano, Gabriel, Temperton, Nigel J., Tiberti, Natalia, Longoni, Silvia Stefania, and others. (2022) SARS-CoV-2 vaccination elicits unconventional IgM specific responses in naïve and previously COVID-19-infected individuals. EBioMedicine, . E-ISSN 2352-3964. (doi:10.1016/j.ebiom.2022.103888) (KAR id:93204)


Background: Currently, evaluation of the IgG antibodies specific for the SARS-CoV-2 Spike protein following vaccination is used worldwide to estimate vaccine response. Limited data are available on vaccine-elicited IgM antibodies and their potential implication in immunity to SARS-CoV-2.

Methods: We performed a longitudinal study to quantify anti-S SARS-CoV-2 IgG and IgM (IgG-S and IgM-S) in health care worker (HCW) recipients of the BNT162b2 vaccine. Samples were collected before administration (T0), at the second dose (T1) and three weeks after T1 (T2). The cohort included 1584 immunologically naïve to SARS-CoV-2 (IN) and 289 with history of previous infection (PI).

Findings: IN showed three patterns of responses: (a) IgG positive/IgM negative (36.1%), (b) coordinated IgM-S/IgG-S responses appearing at T1 (37.4%) and (c) IgM appearing after IgG (26.3%). Coordinated IgM-S/IgG-S responses were associated with higher IgG titres. In IgM-S positive PI, 64.5% were IgM-S positive before vaccination, whereas 32% and 3.5% developed IgM-S after the first and second vaccine dose, respectively. IgM-S positive sera had higher pseudovirus neutralization titres compared to the IgM-S negative.

Interpretation: Coordinated expression of IgG-S and IgM-S after vaccination was associated with a significantly more efficient response in both antibody levels and virus-neutralizing activity. The unconventional IgG-S posi- tive/IgM-S negative responses may suggest a recruitment of cross coronaviruses immunity by vaccination, war- ranting further investigation.

Item Type: Article
DOI/Identification number: 10.1016/j.ebiom.2022.103888
Uncontrolled keywords: SARS-CoV-2; COVID-19; BTN162b2 vaccine; IgG; IgM; Spike
Subjects: Q Science > QR Microbiology > QR355 Virology
Divisions: Divisions > Division of Natural Sciences > Medway School of Pharmacy
Depositing User: Nigel Temperton
Date Deposited: 15 Feb 2022 18:42 UTC
Last Modified: 11 Jan 2024 02:05 UTC
Resource URI: (The current URI for this page, for reference purposes)

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