Ancestral sequence reconstruction has been widely used to test evolution-based hypotheses. The genome of the European tick vector, Ixodes ricinus, encodes for defensin peptides with diverse antimicrobial activities against distantly related pathogens. These pathogens include fungi, Gram-negative, and Gram-positive bacteria, i.e., a wide antimicrobial spectrum. Ticks do not transmit these pathog...

Defensins are a large family of positively-charged antimicrobial peptides that have been implicated innate immunity. Although known for their ability to directly kill bacteria, the mechanisms by which defensins regulate host-pathogen interactions remain elusive. Herein, we deleted entire Defensin gene cluster (3 million base pairs) in keratinocyte-intrinsic manner and observed enhanced suscepti...

Human aand b-defensins are cationic, amphipathic effector peptides of the innate immune system with broad antimicrobial activity [1]. a-defensins are produced by neutrophils (human neutrophil peptides [HNP] 1–4), as well as by epithelial cells in the gut and genitourinary tract (human defensins [HD] 5 and 6). bdefensins (human b-defensins [HBD] 1–4) are constitutively expressed by epithelial ce...

Alpha-defensins are peptides secreted by polymorphonuclear cells and provide antimicrobial protection mediated by disruption of the integrity of bacterial cell walls. Staphylokinase is an exoprotein produced by Staphylococcus aureus, which activates host plasminogen. In this study, we analyzed the impact of interaction between alpha-defensins and staphylokinase on staphylococcal growth. We obse...

Impaired expression of alpha-defensin antimicrobial peptides and overproduction of the proinflammatory cytokine IL-1beta have been associated with inflammatory bowel disease. In this study, we examine the interactions between alpha-defensins and IL-1beta and the role of defensin deficiency in the pathogenesis of inflammatory bowel disease. It was found that matrix metalloproteinase-7-deficient ...

COMMENTARY We would like to comment on the comprehensive review of Karantanos and Gazouli in Annals of Gastroenterology [1] about genetics and innate immunity in inflammatory bowel disease (IBD). The authors appreciate the important role of innate immune sensing and the production of antimicrobial peptides in maintaining the integrity of the mucosal barrier. Pertinent studies on the subject are...

Human polymorphonuclear leukocytes (PMN) contain three antimicrobial and cytotoxic peptides which belong to a family of mammalian granulocyte peptides named defensins. To determine their potential availability for extracellular microbicidal or cytotoxic events, we quantified the extracellular release of defensins after stimulation of human PMN with phorbol myristate acetate and opsonized zymosa...

infections heavily relies on strategies which aim to inhibit and kill pathogens with high specificity. These strategies are very successful and antibiotics have contributed to increasing human life expectancy more than any other class of therapeutic drugs. However, antibiotics are losing efficacy as a result of high selection pressure and rapid resistance development. Thus, strategies that rely...