Immunophysiology of Pregnancy and Lactation
Coordinator : Dan Corral
Scientific Objectives
The immune system plays a fundamental role in the control of host physiology, including organogenesis and tissue remodeling. Such processes initiate at various developmental stages and throughout the lifespan of an organism, allowing for the rapid adaptation to physiological needs. Pregnancy induces extensive physiological remodeling throughout the body to meet the metabolic demands required for supporting fetal development, maintaining maternal health and preparing for lactation. However, how immune mechanisms integrate and coordinate these physiological adaptations during pregnancy and lactation remains incompletely understood.
The objective of the Immunophysiology of Pregnancy and Lactation lab is to define how the immune system actively orchestrates maternal physiological adaptation during pregnancy and lactation, and how immunological perturbations affect these processes.
Our Projects
AXE 1: Immune Orchestration of Maternal Tissue Remodelling
How do immune cells coordinate mammary gland remodelling and functional adaptation during pregnancy and lactation?
Lactogenesis is a pivotal biological process that ensures the newborn receives essential nutrition and immune protection. During pregnancy, the mammary gland undergoes profound physiological remodelling to support neonatal survival through the production of breast milk, a remarkably complex secretion that integrates metabolic, hormonal, and immunological cues. Successful lactogenesis depends on the precise coordination of epithelial differentiation and stromal remodelling. Disruption of this equilibrium can result in delayed or insufficient milk production, with profound consequences for both maternal and infant health. However, the extent to which the immune system influences mammary gland development and function during pregnancy and lactation remains largely unknown.
Our work demonstrates that the maternal adaptive immune system plays a pivotal role in orchestrating mammary gland differentiation during pregnancy and lactation. A pregnancy-associated type 1 immune program, characterized by the emergence of T-bet⁺ lymphoid cells, is established within the mammary gland and contributes to tissue remodeling and lactogenesis. Within this T-bet⁺ compartment, a distinct subset of unconventional mammary intraepithelial lymphocytes (mIELs) emerges, sharing a common thymic progenitor with natural CD8αα⁺ small intestinal intraepithelial lymphocytes (siIELs). Gestation-associated thymic remodeling promotes the expansion of intraepithelial lymphocyte progenitors (IELp), which subsequently differentiate within the mammary gland in an IL-15–dependent manner. These cells localize to the epithelial layer and actively promote the differentiation and functional maturation of both milk-secreting alveolar and contractile myoepithelial compartments.
Figure. Intravital imaging of the mammary gland in non-pregnant (left) and pregnant (right) mice.
T-bet (green), epithelium (red), vasculature (blue).
Credit: © Olena Kamenyeva, NIAID.
By integrating in vivo genetic and organoid models with advanced transcriptomic and imaging approaches, our laboratory investigates how T-bet⁺ immune cells regulate mammary gland development and functional differentiation during pregnancy. We aim to define which components of mammary remodeling are controlled by T-bet⁺ cells (e.g. epithelial differentiation, extracellular matrix organization, and angiogenesis) and to elucidate the molecular mechanisms underlying these processes. Furthermore, we examine how immune-mediated regulation of the mammary gland shapes milk composition and influences neonatal developmental outcomes.
AXE 2: Maternal Inflammatory Disorders and Mammary Remodeling
To what extent do maternal infections and inflammatory disorders affect pregnancy-induced mammary gland remodeling and its impact on lactogenesis?
For a long time, pregnancy was considered a state of generalized maternal immunosuppression associated with increased susceptibility to infection. It is now clear that the maternal immune system is not simply weakened but dynamically modulated across gestation, with tightly regulated shifts in immune activation and tolerance depending on developmental stage. However, while systemic immune adaptations during pregnancy are increasingly recognized, how tissue-specific immunity is reshaped within remodeling organs remains poorly understood.
The impact of infection and inflammation during pregnancy has been extensively studied at the maternal–fetal interface, where dysregulated immune responses are well-established drivers of adverse obstetric and fetal outcomes. Yet, far less attention has been given to how inflammatory challenges influence maternal tissue adaptation and long-term physiological remodeling.
Mammary epithelium is composed of luminal and basal epithelial progenitor populations that undergo extensive differentiation during pregnancy to ensure successful lactogenesis. This tightly coordinated process drives the expansion and functional maturation of milk-secreting alveolar cells and contractile myoepithelial cells, enabling the gland to meet the nutritional demands of the newborn. Our work demonstrates that mammary epithelial differentiation is actively regulated by lymphoid cells during pregnancy, indicating that immune signals are integral components of this developmental program. This raises the question of how inflammatory disorders interfere with immune-mediated epithelial regulation, potentially compromising tissue remodeling, lactogenic function, and neonatal development. Both local mammary and distal infections are associated with alterations in breast milk leukocyte composition, suggesting shifts in the mammary immune landscape. Given the extensive tissue remodeling and the requirement for tightly controlled immune tolerance during pregnancy, the mammary gland may be particularly vulnerable to systemic immune perturbations as maternal-foetal interface. Inflammatory signals could disrupt immune cell recruitment, activation, and functional polarization within the mammary microenvironment, thereby impairing epithelial differentiation, tissue organization, and secretory capacity.
Using experimental models of infection and autoimmune disease, we investigate how inflammatory challenges alter the mammary immune landscape and tissue remodeling, and assess their impact on lactogenesis and neonatal development.
AXE 3: Tolerance and Immune Memory of Pregnancy and Lactation
How do pregnancy and lactation reshape central and peripheral immune tolerance to mammary antigens, and does this remodeling imprint durable tissue-specific immune memory?
Pregnancy represents a unique immunological state in which the maternal immune system must simultaneously support tissue remodeling, maintain tolerance to fetal antigens, and prevent inappropriate responses against self and tissue-specific proteins. The mammary gland, which undergoes extensive differentiation during gestation and lactation, expresses a wide array of milk proteins and tissue-restricted antigens that could potentially trigger autoreactive immune responses. The mammary gland expresses a broad repertoire of tissue-restricted and milk-derived antigens that rise during pregnancy and lactation. These proteins, essential for neonatal nutrition, represent potential targets for autoreactive immune responses. Therefore, the establishment and maintenance of immune tolerance toward mammary and milk antigens are critical to ensure proper tissue remodeling and lactogenic function without triggering inflammation or autoimmunity.
Immune tolerance is established through complementary central and peripheral mechanisms. Central tolerance operates during lymphocyte development in the thymus, where self-reactive T cells are eliminated or diverted toward regulatory lineages. A key role is played by the thymic epithelial compartment, particularly medullary thymic epithelial cells, which express a broad array of tissue-restricted antigens and thereby enable the negative selection or regulatory differentiation of autoreactive clones. Peripheral tolerance subsequently restrains self-reactive cells that escape central selection through regulatory T cells, tolerogenic antigen-presenting cells, and functional inactivation within tissues. These multilayered mechanisms are especially critical during pregnancy, a period characterized by the expression of pregnancy- and lactation-associated antigens. However, whether these tolerance pathways operate as transient adaptations or leave a durable imprint on the mammary immune compartment remains unclear.
The second pregnancy is associated with accelerated mammary gland remodeling and more efficient lactogenic responses, indicating that prior gestation leaves durable biological imprints within the tissue. Indeed, pregnancy induces sustained epigenetic changes in mammary epithelial cells that enhance functional adaptation in subsequent reproductive cycles. In addition, our work has revealed that mammary lymphoid populations display distinct phenotypic characteristics after lactation cease, suggesting that pregnancy-induced immune cells may persist within the gland beyond the initial gestational period. Whether these persistent immune populations contribute to enhanced mammary differentiation and remodeling during a second pregnancy remains to be determined.
Our laboratory aims to define the central and peripheral tolerance mechanisms that establish immune tolerance to mammary and milk-derived antigens during pregnancy, and to determine how pregnancy-induced thymic remodeling reshapes T cell development. We further seek to establish whether these processes lead to durable functional reprogramming of mammary lymphoid cells and how such tissue-specific immunological memory shapes mammary remodeling and lactogenic adaptation across successive reproductive cycles.
Other information
Our team
Publications
2026 |
T-bet-expressing Tr1 cells driven by dietary signals dominate the small intestinal immune landscape Journal Article In: Proc Natl Acad Sci U S A, vol. 123, no. 2, pp. e2520747122, 2026, ISSN: 1091-6490. |
2025 |
Maladaptive immunity to the microbiota promotes neuronal hyperinnervation and itch via IL-17A Journal Article In: Proc Natl Acad Sci U S A, vol. 122, no. 52, pp. e2525146122, 2025, ISSN: 1091-6490. |
Mammary intraepithelial lymphocytes promote lactogenesis and offspring fitness Journal Article In: Cell, vol. 188, no. 6, pp. 1662–1680.e24, 2025, ISSN: 1097-4172. |
2024 |
Sexual dimorphism in skin immunity is mediated by an androgen-ILC2-dendritic cell axis Journal Article In: Science, vol. 384, no. 6692, pp. eadk6200, 2024, ISSN: 1095-9203 (Electronic) 0036-8075 (Linking). |
2023 |
Microbiota configuration determines nutritional immune optimization Journal Article In: Proc Natl Acad Sci U S A, vol. 120, no. 49, pp. e2304905120, 2023, ISSN: 1091-6490. |
2022 |
ILC precursors differentiate into metabolically distinct ILC1-like cells during Mycobacterium tuberculosis infection Journal Article In: Cell Rep, vol. 39, no. 3, pp. 110715, 2022, ISSN: 2211-1247 (Electronic). |
Societal impact
Pregnancy and lactation constitute essential biological adaptations that ensure mammalian survival by providing optimal nutrition and immune protection to the newborn. Yet, the immune mechanisms orchestrating mammary gland remodeling during these transitions remain largely incompletely understood. Building on our recent discovery of T-bet⁺ lymphoid cells as key regulators of lactogenesis, our research program aims to decipher the fundamental principles by which the immune system governs maternal physiological adaptation and how inflammatory perturbations may disrupt this finely tuned equilibrium.
By integrating immunology, tissue physiology, developmental biology, and infectious pathophysiology, this program seeks to define the immune–tissue interactions that drive mammary remodeling, to identify immune signatures associated with optimal versus impaired adaptation, and to link maternal immune regulation to functional outcomes in milk composition and neonatal development. The knowledge generated will contribute to an integrated understanding of the mechanisms that govern maternal physiological adaptation during pregnancy and lactation. By highlighting the structural and regulatory role of the immune system in these major biological transitions, this program will advance recognition of maternal health as a distinct and underexplored field within biomedical research.
Alumni
Collaborations
| Jankovic Dragana , National Institutes of Health, Bethesda, USA |
| Schwartzberg Pamela , National Institutes of Health, Bethesda, USA |
| Bhandoola Avinash , National Institutes of Health, Bethesda, USA |
| Bosselut Rémy, National Institutes of Health, Bethesda, USA |
| Christopher Hunter, University of Pennsylvania, Philadelphia, USA |
| Li Han, Institut Pasteur, Paris, France |
| Neyrolles Olivier, IPBS, Toulouse, France |
Collaborations within the Center:
| Nicolas Blanchard |
| Nicolas Cénac |