Insects can rapidly clear microbial infections by producing a variety of immune-induced molecules including antibacterial and͞or antifungal peptides͞polypeptides. In this report, we present the isolation, structural characterization, and biological properties of two variants of a group of bioactive, slightly cationic peptides, referred to as alloferons. Two peptides were isolated from the blood of an experimentally infected insect, the blow fly Calliphora vicina (Diptera), with the following amino acid sequences: HGVSGHGQH-GVHG (alloferon 1) and GVSGHGQHGVHG (alloferon 2). Although these peptides have no clear homologies with known immune response modifiers, protein database searches established some structural similarities with proteins containing amino acid stretches similar to alloferon. In vitro experiments reveal that the synthetic version of alloferon has stimulatory activities on natural killer lymphocytes, whereas in vivo trials indicate induction of IFN production in mice after treatments with synthetic alloferon. Additional in vivo experiments in mice indicate that alloferon has antiviral and antitumoral capabilities. Taken together, these results suggest that this peptide, which has immunomodulatory properties, may have therapeutic capacities. The fact that insects may produce cytokine-like materials modulating basic mechanisms for human immunity suggests a source of anti-infection and antitumoral biopharmaceuticals.insect innate immunity ͉ cytokine-like ͉ immunomodulatory peptide

Members of the family Picornaviridae, in particular, enteroviruses, represent a serious threat to human health. They are responsible for numerous pathologies ranging from mild disease to fatal outcome. Due to the limited number of safe and effective antivirals against enteroviruses, there is a need for search and development of novel drugs with various mechanisms of activity against enteroviruses-induced pathologies. We studied the effect of dihydroquercetin (DHQ), a flavonoid from larch wood, on the course of pancreatitis of white mice caused by coxsackievirus B4 (CVB4). DHQ was applied intraperitoneally at doses of 75 or 150 mg/kg/day once a day for 5 days postinfection (p.i.) starting on day 1 p.i., and its effect was compared to that of the reference compound ribavirin. The application of DHQ resulted in a dose-dependent decrease in the virus titer in pancreatic tissue, reaching, at the highest dose, 2.4 logs on day 5 p.i. Also, the application of DHQ led to restoration of antioxidant activity of pancreatic tissue that was impaired in the course of pancreatitis. Morphologically, pancreatic tissue of DHQ-treated animals demonstrated less infiltration with inflammatory cells and no signs of tissue destruction compared to placebo-treated mice. Both ribavirin- and DHQ-treated animals developed fewer foci of pancreatic inflammation per mouse, and these foci contained fewer infiltrating cells than those in placebo-treated mice. The effect of DHQ was comparable to or exceeded that of ribavirin. Taken together, our results suggest high antiviral activity of DHQ and its promising potential in complex treatment of viral pancreatitis.

Alloferon is a 13-amino acid peptide isolated from the bacteria-challenged larvae of the blow fly Calliphora vicina. The pharmaceutical value of the peptide has been well demonstrated by its capacity to stimulate NK cytotoxic activity and interferon (IFN) synthesis in animal and human models, as well as to enhance antiviral and antitumor activities in mice. Antiviral and the immunomodulatory effectiveness of alloferon have also been supported clinically proved in patients suffering with herpes simplex virus (HSV) and human papilloma virus (HPV) infections. To elucidate molecular response to alloferon treatment, we initially screened a model cell line in which alloferon enhanced IFN synthesis upon viral infection. Among the cell lines tested, Namalva was chosen for further proteomic analysis. Fluorescence difference gel electrophoresis (DIGE) revealed that the levels of a series of antioxidant proteins decreased after alloferon treatment, while at least three glycolytic enzymes and four heat-shock proteins were increased in their expression levels. Based on the result of our proteomic analysis, we speculated that alloferon may activate the NF-kappaB signaling pathway. IkappaB kinase (IKK) assay, Western blot analysis on IkappaBalpha and its phosphorylated form at Ser 32, and an NF-kappaB reporter assay verified our proteomics-driven hypothesis. Thus, our results suggest that alloferon potentiates immune cells by activating the NF-kappaB signaling pathway through regulation of redox potential. Since NF-kappaB activation is involved in IFN synthesis, our results provide further clues as to how the alloferon peptide may stimulate IFN synthesis.