A novel family of defensin-like peptides from Hermetia illucens with antibacterial properties.

Background: The world faces a major infectious disease challenge. Interest in the discovery, design, or development of antimicrobial peptides (AMPs) as an alternative approach for the treatment of bacterial infections has increased. Insects are a good source of AMPs which are the main effector molecules of their innate immune system.

An attacin antimicrobial peptide, Hill_BB_C10074, from Hermetia illucens with anti-Pseudomonas aeruginosa activity.

Background: There is a global need to develop new therapies to treat infectious diseases and tackle the rise in antimicrobial resistance. To date, the larvae of the Black Solider Fly, Hermetia illucens, have the largest repertoire of antimicrobial peptides derived from insects. Antimicrobial peptides are of particular interest in the exploration of alternative antimicrobials due to their potent action and reduced propensity to induce resistance compared with more traditional antibiotics.

Evaluation of the recombinant proteins RlpB and VacJ as a vaccine for protection against Glaesserella parasuis in pigs.

Background: Glaesserella parasuis, the causative agent of Glӓsser's disease, is widespread in swine globally resulting in significant economic losses to the swine industry. Prevention of Glӓsser's disease in pigs has been plagued with an inability to design broadly protective vaccines, as many bacterin based platforms generate serovar or strain specific immunity. Subunit vaccines are of interest to provide protective immunity to multiple strains of G.

A Secreted RNA Binding Protein Forms RNA-Stabilizing Granules in the Honeybee Royal Jelly.

RNA flow between organisms has been documented within and among different kingdoms of life. Recently, we demonstrated horizontal RNA transfer between honeybees involving secretion and ingestion of worker and royal jellies. However, how the jelly facilitates transfer of RNA is still unknown.

A novel and sensitive functional assay for complement Factor I based on the third proteolytic clip of C3b.

A sensitive assay for the functional activity of complement Factor I is described. This is based on its third proteolytic clip whereby Factor I cleaves cell-bound iC3b to cell-bound C3dg and soluble C3c, thereby abolishing conglutination of the cells. Factor H is required as a co-factor for Factor I activity.

Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs.

is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins.

Experimental confirmation of the C3 tickover hypothesis by studies with an Ab (S77) that inhibits tickover in whole serum.

The complement component 3 (C3) tickover hypothesis was put forward in the early 1970s to account for the spontaneous activation of the alternative complement pathway that occurs after the genetic absence or depletion of Factor I, the enzyme that is essential for the breakdown of C3b. The hypothesis was widely accepted, but experimental demonstration of the tickover was elusive. A phage Ab against C3b that inhibited the alternative complement pathway, but not the classical pathway, was described in 2009.

Further studies of the down-regulation by Factor I of the C3b feedback cycle using endotoxin as a soluble activator and red cells as a source of CR1 on sera of different complotype.

In this paper we have extended our earlier studies of the action of increasing Factor I concentration on complement activation by using a soluble activator, lipopolysaccharide (LPS) endotoxin, and using human erythrocytes as a source of CR1 - the co-factor needed for the final clip of iC3b to C3dg by Factor I. Using this more physiological system, the results show that we can predict that a quite modest increase in Factor I concentration - 22 µg/ml of extra Factor I - will convert the activity of the highest risk sera to those of the lowest risk. Preliminary experiments have been performed with erythrocytes allotyped for CR1 number.

A fusion intermediate gp41 immunogen elicits neutralizing antibodies to HIV-1.

The membrane-proximal external region (MPER) of the human immunodeficiency virus, type 1 (HIV-1) envelope glycoprotein subunit gp41 is targeted by potent broadly neutralizing antibodies 2F5, 4E10, and 10E8. These antibodies recognize linear epitopes and have been suggested to target the fusion intermediate conformation of gp41 that bridges viral and cellular membranes. Anti-MPER antibodies exert different degrees of membrane interaction, which is considered to be the limiting factor for the generation of such antibodies by immunization.

Complotype affects the extent of down-regulation by Factor I of the C3b feedback cycle in vitro.

Sera from a large panel of normal subjects were typed for three common polymorphisms, one in C3 (R102G) and two in Factor H (V62I and Y402H), that influence predisposition to age-related macular degeneration and to some forms of kidney disease. Three groups of sera were tested; those that were homozygous for the three risk alleles; those that were heterozygous for all three; and those homozygous for the low-risk alleles. These groups vary in their response to the addition of exogenous Factor I when the alternative complement pathway is activated by zymosan.

Mixed adjuvant formulations reveal a new combination that elicit antibody response comparable to Freund's adjuvants.

Adjuvant formulations capable of inducing high titer and high affinity antibody responses would provide a major advance in the development of vaccines to viral infections such as HIV-1. Although oil-in-water emulsions, such as Freund's adjuvant (FCA/FIA), are known to be potent, their toxicity and reactogenicity make them unacceptable for human use. Here, we explored different adjuvants and compared their ability to elicit antibody responses to FCA/FIA.

Direct detection of disease associated prions in brain and lymphoid tissue using antibodies recognizing the extreme N terminus of PrPC.

A simple diagnostic test is described for the detection of TSE in bovine, ovine and human brain and lymphoid tissue that obviates the use of proteinase K as a discriminating reagent. The immunoassay utilises high affinity anti-peptide antibodies that appear blind to the normal isoform of prion protein (PrP(C)). These reagents have been produced with novel N-terminal chimeric peptides and we hypothesise that the retention and stability of the extreme N-terminus of PrP in the disease-associated aggregate makes it an operationally specific marker for TSE.

Streptococcal DRS (distantly related to SIC) and SIC inhibit antimicrobial peptides, components of mucosal innate immunity: a comparison of their activities.

"Streptococcal inhibitor of complement" (SIC) and "distantly related to SIC" (DRS) are related virulence factors secreted by M1 and M12 strains of GAS, respectively. The human mucosal innate immune system, important components of which are beta-defensins, secretory leukocyte proteinase inhibitor (SLPI) and lysozyme, provides the first line of defence against microorganisms. We report the interaction between DRS and these proteins; further investigations into the interaction of SIC with the beta-defensins; and compare the sensitivity of M12 and M1 GAS to SLPI.

Inhibition of antimicrobial peptides by group A streptococci: SIC and DRS.

SIC (streptococcal inhibitor of complement) is a 31 kDa protein secreted by a few highly virulent strains of GAS (group A streptococci), predominantly by the M1 strain. Initially described as an inhibitor of the membrane attack complex of complement, it has turned out to be a polyfunctional inhibitor of the innate mucosal immune response. The SIC protein sequence contains three domains: an N-terminal SRR (short repeat region), followed by three longer tandem repeats [LRR (long repeat region)] and a C-terminal PRR (proline-rich region).

Attribution of the various inhibitory actions of the streptococcal inhibitor of complement (SIC) to regions within the molecule.

Some strains of Streptococcus pyogenes secrete a virulence factor called the streptococcal inhibitor of complement (SIC) function. SIC is a polyfunctional protein that interacts with a number of host proteins and peptides, especially with those that are involved in host defense systems. In addition to inhibiting the complement-mediated lysis of cells, SIC inhibits lysozyme, secretory leukocyte proteinase inhibitor, and beta-defensins.

Identification and characterisation of hyaluronate lyase from Streptococcus suis.

Hyaluronate lyase, which catalyses the degradation of hyaluronic acid (HA), has been described from several pathogenic streptococcal species. We describe, for the first time, identification and purification of hyaluronate lyase from the zoonotic pig pathogen Streptococcus suis. We have cloned the hyaluronate lyase gene from S.

The interaction of streptococcal inhibitor of complement (SIC) and its proteolytic fragments with the human beta defensins.

Streptococcal inhibitor of complement (SIC) is a 31 kDa extracellular protein produced by a few highly virulent strains of Streptococcus pyogenes (in particular the M1 strain). It has been shown additionally to inhibit four further components of the mucosal innate response-lysozyme, secretory leucocyte proteinase inhibitor, human alpha-defensin 1 and the cathelicidin LL-37 which are all bactericidal against Group A Streptococci (GAS). We now show that SIC also inhibits variably the antibacterial action of hBD-1, -2 and -3.

Determination of CD59 protein in normal human serum by enzyme immunoassay, using octyl-glucoside detergent to release glycosyl-phosphatidylinositol-CD59 from lipid complex.

In this study we have optimised the enzyme immunoassay (ELISA) to quantify CD59 antigen in human serum or plasma. The glycosyl-phosphatidylinositol (GPI)-linked form of CD59 is known to complex with serum high-density lipoprotein. For ELISA optimisation, therefore, we investigated the effect of detergents, added to the sample diluent, on the determined values of CD59.

Streptococcal inhibitor of complement inhibits two additional components of the mucosal innate immune system: secretory leukocyte proteinase inhibitor and lysozyme.

Streptococcal inhibitor of complement (SIC) is a 31-kDa extracellular protein of a few, very virulent, strains of Streptococcus pyogenes (particularly M1 strains). It is secreted in large quantities (about 5 mg/liter) and inhibits complement lysis by blocking the membrane insertion site on C5b67. We describe investigations into the interaction of SIC with three further major components of the innate immune system found in airway surface liquid, namely, secretory leukocyte proteinase inhibitor (SLPI), lysozyme, and lactoferrin.

Streptococcal inhibitor of complement (SIC) inhibits the membrane attack complex by preventing uptake of C567 onto cell membranes.

Streptococcal inhibitor of complement (SIC) was first described in 1996 as a putative inhibitor of the membrane attack complex of complement (MAC). SIC is a 31 000 MW protein secreted in large quantities by the virulent Streptococcus pyogenes strains M1 and M57, and is encoded by a gene which is extremely variable. In order to study further the interactions of SIC with the MAC, we have made a recombinant form of SIC (rSIC) in Escherichia coli and purified native M1 SIC which was used to raise a polyclonal antibody.

Antigen S1, encoded by the MIC1 gene, is characterized as an epitope of human CD59, enabling measurement of mutagen-induced intragenic deletions in the AL cell system.

S1 cell membrane antigen is encoded by the MIC1 gene on human chromosome 11. This antigen has been widely used as a marker for studies in gene mapping or in analysis of mutagen-induced gene deletions/mutations, which utilized the human-hamster hybrid cell-line, AL-J1, carrying human chromosome 11. Evidence is presented here which identifies S1 as an epitope of CD59, a cell membrane complement inhibiting protein.

Comparison of C1q-receptors on rat microglia and peritoneal macrophages.

A comparison of the expression and ligand specificity of the C1q (first complement component) receptor on rat microglia and peritoneal macrophages was made. This revealed that radiolabelled C1q was competed from the peritoneal macrophages with intact C1q, and additively displaced by calf-skin collagen and purified C1q globular heads, suggesting the presence of at least two receptors. This was in contrast to microglia, where radiolabelled C1q was displaced with intact C1q and to a modest degree with collagen, but not with globular heads.

Rapid isolation and biochemical characterization of rat C1 and C1q.

Using a human IgG-Sepharose column to which rabbit anti-human IgG was bound (rabbit anti-human/human IgG-Sepharose), human and rat C1 or C1q were isolated from serum in a single step, and the C1q further purified to homogeneity by FPLC. This procedure allowed the rapid isolation of haemolytically active C1 or C1q, with a yield equal to or greater than published methods. The availability of human and rat C1q allowed comparison of the two molecules, revealing differences in their mobility on SDS-PAGE as well as on agarose gel electrophoresis.