High concentrations of neutrophil defensins from airway and blood have been reported in patients with inflammatory lung diseases, but their exact role is unclear. We investigated the direct effect of defensins on the lungs of mice. Intratracheal instillation of purified defensins (5-30 mg/kg) induced a progressive reduction in peripheral arterial O(2) saturation, increased lung permeability, an...

Mammals have evolved complex self-defence mechanisms to protect themselves from infection. This innate immune system comprises a large family of hundreds of peptides and proteins which have potent antibiotic activity at nanomolar concentrations. The defensins are a group of small cationic peptides which contain a high proportion of positively charged and hydrophobic amino acids. Their exact mec...

The first cyclic peptide discovered in animals is an antimicrobial octadecapeptide that is expressed in leukocytes of rhesus monkeys. The peptide, termed rhesus θ-defensin 1 (RTD-1) is the prototype of a new family of antimicrobial peptides, which like the previously characterized αand β-defensin families, possesses broad spectrum microbicidal activities against bacteria, fungi, and protects mo...

The release of gene-encoded antimicrobial peptides by epithelial cells is thought to contribute to innate mucosal immunity. Defensins are a predominant class of such antimicrobial peptides in mammals. These cysteine-rich cationic peptides have antibiotic activity against a wide range of bacteria and other microbes. In the mammalian small intestine, Paneth cells at the base of the crypts of Lieb...

Human defensins are innate immune defense peptides with a remarkably broad repertoire of anti-pathogen activities. In addition to modulating immune response, inflammation, and angiogenesis, disintegrating bacterial membranes, and inactivating bacterial toxins, defensins are known to intercept various viruses at different stages of their life cycles, while remaining relatively benign towards hum...

Proliferative retinopathies, such as those complicating prematurity and diabetes, are major causes of blindness. A prominent feature of these retinopathies is excessive neovascularization, which is orchestrated by the hypoxia-induced vascular endothelial growth factor (VEGF) stimulating endothelial cells and the integrin-mediated adhesive interactions of endothelial cells with extracellular mat...

Profound loss of CD4+ T cells, progressive impairment of the immune system, inflammation, and sustained immune activation are the characteristics of human immunodeficiency virus-1 (HIV-1) infection. Innate immune responses respond immediately from the day of HIV infection, and a thorough understanding of the interaction between several innate immune cells and HIV-1 is essential to determine to ...

Three oyster defensin variants (Cg-Defh1, Cg-Defh2, and Cg-Defm) were produced as recombinant peptides and characterized in terms of activities and mechanism of action. In agreement with their spectrum of activity almost specifically directed against Gram-positive bacteria, oyster defensins were shown here to be specific inhibitors of a bacterial biosynthesis pathway rather than mere membrane-a...

BACKGROUND During pregnancy the immune system of the mother must protect any activation that may negatively affect the fetus. Changes in susceptibility to infection as well as resolution of some autoimmune disorders represent empirical evidence for pregnancy related alterations in immunity. Sex hormones reach extremely high levels during pregnancy and have been shown to have direct effects on m...

background: the rise of opportunistic fungal infections highlights the need for development of new antimicrobial agents. antimicrobial peptides (amps) and antifungal peptides (afps) are among the agents with minimal resistance being developed against them, therefore they can be used as structural templates for design of new antimicrobial agents. methods: in the present study four antifungal pep...