Secretory IgA and T Cells Targeting SARS-CoV-2 Spike Protein Are Transferred to the Breastmilk Upon mRNA Vaccination

• Autor(a) principal: Gonçalves, J
• Data de Publicação: 2021
• Outros Autores: Juliano, AM, Charepe, N, Alenquer, M, Athayde, D, Ferreira, F, Archer, M, Amorim, MJ, Serrano, F, Soares, H
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.17/3960
• topic: MAC MED MAF; Antibodies, Viral / blood; Antibodies, Viral / immunology; COVID-19 / immunology; COVID-19 / prevention & control; COVID-19 Vaccines / immunology*; Female; Humans; Immunity, Maternally-Acquired; Immunoglobulin A, Secretory / immunology*; Lactation / immunology; Memory B Cells / immunology; Milk, Human / immunology*; SARS-CoV-2 / immunology*; Spike Glycoprotein, Coronavirus / immunology*; T-Lymphocytes / immunology*; mRNA Vaccines / immunology; Vaccination

In view of the scarcity of data to guide decision making, we evaluated how BNT162b2 and mRNA-1273 vaccines affect the immune response in lactating women and the protective profile of breastmilk. Compared with controls, lactating women had a higher frequency of circulating RBD memory B cells and higher anti-RBD antibody titers but similar neutralizing capacity. We show that upon vaccination, immune transfer to breastmilk occurs through a combination of anti-spike secretory IgA (SIgA) antibodies and spike-reactive T cells. Although we found that the concentration of anti-spike IgA in breastmilk might not be sufficient to directly neutralize SARS-CoV-2, our data suggest that cumulative transfer of IgA might provide the infant with effective neutralization capacity. Our findings put forward the possibility that breastmilk might convey both immediate (through anti-spike SIgA) and long-lived (via spike-reactive T cells) immune protection to the infant. Further studies are needed to address this possibility and to determine the functional profile of spike T cells.