Human transferrin receptor can mediate SARS-CoV-2 infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been detected in almost all organs of coronavirus disease-19 patients, although some organs do not express angiotensin-converting enzyme-2 (ACE2), a known receptor of SARS-CoV-2, implying the presence of alternative receptors and/or co-receptors. Here, we show that the ubiquitously distributed human transferrin receptor (TfR), which binds to diferric transferrin to traffic between membrane and endosome for the iron delivery cycle, can ACE2-independently mediate SARS-CoV-2 infection. Human, not mouse TfR, interacts with Spike protein with a high affinity (K ~2.

Transferrin Is Up-Regulated by Microbes and Acts as a Negative Regulator of Immunity to Induce Intestinal Immunotolerance.

Cross-talks (e.g., host-driven iron withdrawal and microbial iron uptake between host gastrointestinal tract and commensal microbes) regulate immunotolerance and intestinal homeostasis.

An inhibitor of leukotriene-A hydrolase from bat salivary glands facilitates virus infection.

SignificanceAn immunosuppressant protein (MTX), which facilitates virus infection by inhibiting leukotriene A hydrolase (LTAH) to produce the lipid chemoattractant leukotriene B (LTB), was identified and characterized from the submandibular salivary glands of the bat . To the best of our knowledge, this is a report of an endogenous LTAH inhibitor in animals. MTX was highly concentrated in the bat salivary glands, suggesting a mechanism for the generation of immunological privilege and immune tolerance and providing evidence of viral shedding through oral secretions.

Iron-Deficiency and Estrogen Are Associated With Ischemic Stroke by Up-Regulating Transferrin to Induce Hypercoagulability.

Rationale: Epidemiological studies have identified an associate between iron deficiency (ID) and the use of oral contraceptives (CC) and ischemic stroke (IS). To date, however, the underlying mechanism remains poorly understood. Both ID and CC have been demonstrated to upregulate the level and iron-binding ability of Tf (transferrin), with our recent study showing that this upregulation can induce hypercoagulability by potentiating FXIIa/thrombin and blocking antithrombin-coagulation proteases interactions.

Purification and characterization of a novel anti-coagulant from the leech Hirudinaria manillensis.

Protease inhibitors have been reported rarely from the leech . In this study, we purified a novel protease inhibitor (bdellin-HM-2) with anticoagulant properties from . With a molecular weight of 1.

As-CATH4 and 5, two vertebrate-derived natural host defense peptides, enhance the immuno-resistance efficiency against bacterial infections in Chinese mitten crab, Eriocheir sinensis.

Host defense peptides (HDPs), a class of conserved components of animal innate immune system, possess direct antimicrobial activities against invading pathogens and broadly participate in boosting and modulating host immune responses. Cathelicidins is an important family of HDPs that has been identified exclusively in vertebrates. Considering the relatively conserved innate immune system between invertebrates and vertebrates, it is speculated that HDPs from vertebrates may also possess modulating functions on invertebrate innate immune system.