Department of Immunopathology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan.
Published: July 2010
AI Article Synopsis
Article Abstract
The recirculation of leukocytes is essential for proper immune responses. However, the molecular mechanisms that regulate the entry of leukocytes into the lymphatics remain unclear. Here we show that plexin-A1, a principal receptor component for class III and class VI semaphorins, was crucially involved in the entry of dendritic cells (DCs) into the lymphatics. Additionally, we show that the semaphorin Sema3A, but not Sema6C or Sema6D, was required for DC transmigration and that Sema3A produced by the lymphatics promoted actomyosin contraction at the trailing edge of migrating DCs. Our findings not only demonstrate that semaphorin signals are involved in DC trafficking but also identify a previously unknown mechanism that induces actomyosin contraction as these cells pass through narrow gaps.
Specialized memory CD4 T cells that reside long-term within tissues are critical components of immunity at portals of pathogen entry. In the lung, such tissue-resident memory (TRM) cells are activated rapidly after infection and promote local inflammation to control pathogen levels before circulating T cells can respond. However, optimal clearance of Influenza A virus can require TRM and responses by other virus-specific T cells that reach the lung only several days after their activation in secondary lymphoid organs.
Salt-sensitive blood pressure is a clinical phenotype defined as exaggerated blood pressure responses to salt loading and salt depletion. This characteristic occurs in 25% of the general population and 50% of patients with hypertension and contributes to the pathogenesis of hypertension in some patients. Hypertension is associated with chronic inflammatory responses and has immune cell accumulation in several hypertensive target organs, including the brain, kidneys, heart, blood vessels, and the perivascular adipose tissue, and these cellular responses likely exacerbate hypertension.
Dendritic cells (DCs) are crucial in understanding how HIV infects individuals, particularly in the female genital tract, which is a primary entry point for the virus.
Researchers studied different types of genital DCs at the single cell level to see how they respond to HIV right after exposure.
They discovered distinct DC subsets with unique responses: CD14+ DCs primarily triggered an antimicrobial response, while CD1c+ DC2s activated inflammasome pathways and interferon responses, highlighting potential strategies for preventing HIV infection.
At the presynaptic active zone, voltage-gated Ca channels (Cas) mediate Ca entry for neurotransmitter release. Cas are a large family of proteins, and different subtypes have distinct localizations across neuronal somata, dendrites and axons. Here, we review how neurons establish and maintain a specific Ca repertoire at their active zones.
- The bursa of Fabricius (BF) is a crucial organ in birds for B-cell development, arising from the cloaca during embryonic growth.
- Researchers found that specific precursors for B cells, macrophages, and dendritic cells migrate to the BF, with a new cell type, EIV-E12+, playing a key role in initiating the formation of lymphoid follicles.
- Experiments with chick-duck and chick-quail combinations indicate that EIV-E12+ cells act as transient inducers for lymphoid follicle formation, but they aren't direct precursors of B or dendritic cells.
