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ORIGINAL RESEARCH article

Front. Immunol.
Sec. Viral Immunology
Volume 15 - 2024 | doi: 10.3389/fimmu.2024.1481416
This article is part of the Research Topic The Immunological Effects of Respiratory Viruses during Pregnancy and Breastfeeding View all 3 articles

Infant respiratory infections modulate lymphocyte homing to breast milk

Provisionally accepted
Yingying Zheng Yingying Zheng 1Simone Correa-Silva Simone Correa-Silva 1Regina Maria Rodrigues Regina Maria Rodrigues 1Eloisa Corrêa De Souza Eloisa Corrêa De Souza 2Fernanda A Macaferri da Fonseca Fernanda A Macaferri da Fonseca 1Alfredo Elias Gilio Alfredo Elias Gilio 2Magda Carneiro-Sampaio Magda Carneiro-Sampaio 1Patricia Palmeira Patricia Palmeira 3*
  • 1 Department of Pediatrics, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo, São Paulo, Brazil
  • 2 Department of Pediatrics, Hospital Universitario, Universidade de Sao Paulo, São Paulo, Brazil
  • 3 Laboratory of Clinical Pediatrics, Laboratory of Medical Research, Clinical Hospital, Faculty of Medicine, University of São Paulo, São Paulo, Brazil

The final, formatted version of the article will be published soon.

    Chemokines and their receptors are essential for leukocyte migration to several tissues, including human milk. Here, we evaluated the homing of T and B lymphocyte subsets to breast milk in response to ongoing respiratory infections in the nursing infant. Blood and mature milk were collected from healthy mothers of nurslings with respiratory infections (Group I) and from healthy mothers of healthy nurslings (Group C). Total lymphocyte, T and B cells, their subset numbers, and the expression of the homing receptors CCR5, CCR6, CCR10, and CXCR3 in these cells were evaluated in milk. Maternal serum and milk chemokine, cytokine, and IgA and IgG antibody levels were also quantified. All milk lymphocyte numbers were greater in Group I than in Group C. All CD4 T-cell subsets expressing CCR5, CCR6, and CXCR3 were higher in Group I. Within the CD8 T-cell subsets, only CCR6 and CXCR3 were higher in Group I, while CCR5 expression was higher in Group I exclusively for activated CD8 T cells. Group I showed greater numbers of all CCR6+ B-cell subsets and CXCR3+ naive B cells and plasma cells than did Group C. Infection of the nurslings promoted increased CCL20, CXCL10, IL-6, IL-8, total IgA, and IgG levels in the milk.Respiratory infections in nursing infants stimulate an increase in cytokines and chemokines in breast milk, facilitating the recruitment and activation of lymphocytes. This process may promote immunological tolerance and help in the maturation of the infant's immune system, providing an additional strategy for passive maternal-infant protection.

    Keywords: breast milk, Infant respiratory infections, mucosal immunology, Lymphocyte homing, chemokine receptor

    Received: 15 Aug 2024; Accepted: 16 Dec 2024.

    Copyright: © 2024 Zheng, Correa-Silva, Rodrigues, Corrêa De Souza, Macaferri da Fonseca, Gilio, Carneiro-Sampaio and Palmeira. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Patricia Palmeira, Laboratory of Clinical Pediatrics, Laboratory of Medical Research, Clinical Hospital, Faculty of Medicine, University of São Paulo, São Paulo, Brazil

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