Mucosal Immunity

We review our current understanding of adaptive immune responses to the fetoplacental allograft, emphasizing the divergent responses observed for trophoblast- v

Human milk provides a very wide range of nutrients and bioactive components, including immune factors, human milk oligosaccharides, and a commensal microbiota. These factors are essential for interconnected processes including immunity programming and the development of a normal infant gastrointestinal microbiome. Newborn immune protection mostly relies on maternal immune factors provided through milk. However, studies dealing with an in-depth profiling of the different immune compounds present in human milk and with the assessment of their natural variation in healthy women from different populations are scarce. In this context, the objective of this work was the detection and quantification of a wide array of immune compounds, including innate immunity factors (IL1β, IL6, IL12, INFγ, TNFα), acquired immunity factors (IL2, IL4, IL10, IL13, IL17), chemokines (IL8, Groα, MCP1, MIP1β), growth factors (IL5, IL7,EGF, GCSF, GMCSF,TGFβ2) and immunoglobulins (IgA, IgG, IgM), in milk produced by healthy women of different ethnicities living in different geographic, dietary, socio-economic, and environmental settings. Among the analyzed factors, IgA, IgG, IgM, EGF, TGFβ2, IL7, IL8, Groα, MIP1β were detected in all or most of the samples collected in each population and, therefore, this specific set of compounds might be considered as the “core” soluble immune factors in milk produced by healthy women worldwide. This approach may help define which immune factors are (or are not) common in milk produced by women living in various conditions, and to identify host, lifestyle, and environmental factors that affect the immunological composition of this complex biological fluid.

The potential impact of cervicovaginal bacteria on HIV susceptibility is not well-defined.
Gosmann et al. (2017) identify anaerobic cervicovaginal bacterial communities and
specific taxa highly prevalent in young healthy South African women that increase
their HIV risk. These findings might be leveraged to reduce HIV acquisition in women.

The role of the maternal immune system in reproductive success in humans remains controversial. Here we focus on the events that occur in the maternal decidua during the first few weeks of human pregnancy, because this is the site at which maternal leukocytes initially interact with and can recognize fetal trophoblast cells, potentially involving allorecognition by both T cells and natural killer (NK) cells. NK cells are the dominant leukocyte population in first-trimester decidua, and genetic studies point to a role of allorecognition by uterine NK cells in establishing a boundary between the mother and the fetus. By contrast, definitive evidence that allorecognition by decidual T cells occurs during the first trimester is lacking. Thus, our view is that during the crucial period when the placenta is established, damaging T cell-mediated adaptive immune responses towards placental trophoblast are minimized, whereas NK cell allorecognition contributes to successful implantation and healthy pregnancy. Major human pregnancy disorders arise from the failure of placental trophoblast to access sufficient supplies of maternal oxygen and nutrients. Key to understanding this process are the interactions that occur early in pregnancy between trophoblast cells that invade the decidua and maternal uterine immune cells.

Mucosal Immunology is the official publication of the Society of Mucosal Immunology (SMI). It aims to provide a forum for both basic and clinical scientists to discuss all aspects of immunity and inflammation involving mucosal tissues. The journal reflects the interests of scientists studying gastrointestinal, pulmonary, nasopharyngeal, oral, ocular, and genitourinary immunology through the publication of original research articles, scholarly reviews, and timely commentaries, editorials and letters.

Tenofovir is a preexposure drug used to prevent HIV infection. In clinical trials, tenofovir was effective for men, but not women. Klatt et al. now show that tenofovir efficacy in women depends on the composition of the vaginal microbiome (see the Perspective by Tuddenham and Ghanem). In a clinical trial of 688 women, tenofovir was three times as effective among those with a Lactobacillus -dominant vaginal microbiome as it was among other women. Gardnerella vaginalis tended to predominate in the women for whom tenofovir was less effective, and the authors found that the organism could rapidly metabolize and thereby inactivate the drug.

Science , this issue p. [938][1]; see also p. [907][2]

[1]: /lookup/doi/10.1126/science.aai9383
[2]: /lookup/doi/10.1126/science.aan6103

More than ten thousand liters of air enter the lungs on a given day, but it’s not just oxygen that fills the lungs; pathogens and pollutants also hit