@article{3664d3a21cbb43eda2374a42527a6020,
title = "Secretory IgA and T cells targeting SARS-CoV-2 spike protein are transferred to the breastmilk upon mRNA vaccination",
abstract = "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.",
keywords = "breastmilk T cells, COVID-19, lactating women, maternal vaccination, memory B cells, milk-transferred SARS-CoV-2 protection, milk-transferred spike-reactive T cells, mRNA vaccine, plasmablasts, spike SIgA",
author = "Juliana Gon{\c c}alves and Juliano, {A. Margarida} and N{\'a}dia Charepe and Marta Alenquer and Diogo Athayde and Filipe Ferreira and Margarida Archer and Amorim, {Maria Jo{\~a}o} and F{\'a}tima Serrano and Helena Soares",
note = "Funding Information: We are very grateful to all study participants. We thank Cl?udia Andrade (CEDOC Flow Cytometry Platform), Manuela Correia, Yasmina Orraca, Daniela Silva, and Jos? Ramalho for support. This work was supported by European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and by Gilead G?nese (PGG/009/2017) grants to H.S. RESEARCH 4 COVID-19 to M.J.A. European Union (EU) Horizon 2020 (H2020) grants 823780 and 87103, and Funda??o para a Ci?ncia e Tecnologia (FCT) MOSTMICRO-ITQB grants UIDB/04612/2020 and UIDP/04612/2020 to M. Archer and D.A. J.G. D.A. M.J.A. and H.S. are supported by FCT through grants PD/BD/128343/2017 and 02/SAICT/2020/072552, BD/147987/2019, CEECIND/02373/2020, and CEECIND/01049/2020, respectively. The graphical abstract was created using BioRender.com. J.G. A.M.J. M. Alenquer, D.A. and F.F. designed and performed experiments and analyzed the data. N.C. F.S. J.G. and H.S. enrolled the subjects and collected demographic data. M.J.A. and M. Archer provided critical expertise. H.S. conceptualized the study, designed experiments, analyzed the data, supervised the project, and wrote the manuscript. All authors discussed the results and commented on the manuscript. The authors declare no competing interests. Funding Information: We are very grateful to all study participants. We thank Cl{\'a}udia Andrade (CEDOC Flow Cytometry Platform), Manuela Correia, Yasmina Orraca, Daniela Silva, and Jos{\'e} Ramalho for support. This work was supported by European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and by Gilead G{\'e}nese ( PGG/009/2017 ) grants to H.S., RESEARCH 4 COVID-19 to M.J.A., European Union (EU) Horizon 2020 (H2020) grants 823780 and 87103 , and Funda{\c c}{\~a}o para a Ci{\^e}ncia e Tecnologia (FCT) MOSTMICRO-ITQB grants UIDB/04612/2020 and UIDP/04612/2020 to M. Archer and D.A. J.G., D.A., M.J.A., and H.S. are supported by FCT through grants PD/BD/128343/2017 and 02/SAICT/2020/072552 , BD/147987/2019 , CEECIND/02373/2020 , and CEECIND/01049/2020 , respectively. The graphical abstract was created using BioRender.com . ",
year = "2021",
month = dec,
day = "21",
doi = "10.1016/j.xcrm.2021.100468",
language = "English",
volume = "2",
journal = "Cell Reports Medicine",
issn = "2666-3791",
publisher = "Cell Press",
number = "12",
}