Pregnancy enhances antiviral immunity independent of type I IFN but dependent on IL-17-producing γδ T cells in the nasal mucosa.

Pregnancy is associated with profound changes in immunity. However, pregnancy-related respiratory immune adaptations in response to influenza infection and their impact on disease severity remain unclear. Here, we describe, in a preclinical model of mid-gestation pregnancy, a mechanism of enhanced host defense against influenza A virus (IAV) localized to the nasal cavity that limits viral replication and reduces the magnitude of intrapulmonary immune responses.

BCG immunization induces CX3CR1 effector memory T cells to provide cross-protection via IFN-γ-mediated trained immunity.

After a century of using the Bacillus Calmette-Guérin (BCG) vaccine, our understanding of its ability to provide protection against homologous (Mycobacterium tuberculosis) or heterologous (for example, influenza virus) infections remains limited. Here we show that systemic (intravenous) BCG vaccination provides significant protection against subsequent influenza A virus infection in mice. We further demonstrate that the BCG-mediated cross-protection against influenza A virus is largely due to the enrichment of conventional CD4 effector CX3CR1 memory αβ T cells in the circulation and lung parenchyma.

Neonatal imprinting of alveolar macrophages via neutrophil-derived 12-HETE.

Resident-tissue macrophages (RTMs) arise from embryonic precursors, yet the developmental signals that shape their longevity remain largely unknown. Here we demonstrate in mice genetically deficient in 12-lipoxygenase and 15-lipoxygenase (Alox15 mice) that neonatal neutrophil-derived 12-HETE is required for self-renewal and maintenance of alveolar macrophages (AMs) during lung development. Although the seeding and differentiation of AM progenitors remained intact, the absence of 12-HETE led to a significant reduction in AMs in adult lungs and enhanced senescence owing to increased prostaglandin E production.

Transplacental and Breast Milk Transfer of IgG1 Are Both Required for Prolonged Protection of Offspring Against Influenza A Infection.

The immune system during pregnancy teeters between maintaining fetal tolerance and providing protection against pathogens. Due to this delicate balance, pregnant women and their offspring often have increased susceptibilities to infection. During the first year of life, infant immunity against infection is mainly mediated passively transferred maternal antibodies.

Dietary protein intake in older adults undergoing cardiac surgery.

Background: Older adults undergoing major surgery have increased protein requirements in the postoperative period, but there are limited data describing actual protein intake following cardiac surgery.

Methods And Results: We performed a prospective sub-study within a registry of older adults ≥60 years of age undergoing cardiac surgery at a tertiary care centre. A dietician administered a food frequency questionnaire before surgery and 1-4 months after surgery.

Nucleic Acid Sensing in Allergic Disorders.

Recent advances indicate that there is crosstalk between allergic disorders and nucleic acid sensing. Triggers that activate inflammatory mechanisms via nucleic acid sensors affect both allergic phenotypes and anti-viral responses, depending on the timing and the order of exposure. Viral respiratory infections, such as those caused by the rhinovirus, influenza, and respiratory syncytial virus, are the most frequent cause of significant asthma exacerbations through effects mediated predominantly by TLR3.