Development of a recombinant Fab-fragment based electrochemical immunosensor for deoxynivalenol detection in food samples

A reliable and cost-effective electrochemical method for the detection of deoxynivalenol (DON) in cereals and cereal-based food samples based on the use of a novel anti-DON Fab fragment is presented. The analytical system employed, Enzyme-Linked-Immunomagnetic-Electrochemical (ELIME) assay, is based on the use of immunomagnetic beads (IMBs) coupled with eight magnetized screen-printed electrodes (8-mScPEs) as electrochemical transducers.

Intravaginal immunization using the recombinant HIV-1 clade-C trimeric envelope glycoprotein CN54gp140 formulated within lyophilized solid dosage forms

Vaccine-mediated prevention of primary HIV-1 infection at the heterosexual mucosal portal of entry may be facilitated by highly optimised formulations or drug delivery devices for intravaginal (i.vag) immunization. Previously we described hydroxyethylcellulose (HEC)-based rheologically structured gel vehicles (RSVs) for vaginal immunization of an HIV-1 vaccine candidate, a soluble recombinant trimeric HIV-1 clade-C envelope glycoprotein designated CN54gp140. Here we investigated the efficacy of lyophilized solid dosage formulations (LSDFs) for prolonging antigen stability and as i.vag delivery modalities. LSDFs were designed and developed that upon i.vag administration they would reconstitute with the imbibing of vaginal fluid to mucoadhesive, site-retentive semi-solids. Mice were immunized with lyophilized equivalents of (i) RSVs, (ii) modified versions of the RSVs more suited to lyophilization (sodium carboxymethyl cellulose (NaCMC)-based gels) and (iii) Carbopol® gel, all containing CN54gp140. NaCMC-based LSDFs provided significantly enhanced antigen stability compared to aqueous-based RSVs. Rheological analysis indicated the NaCMC-based LSDFs would offer enhanced vaginal retention in woman compared to more conventional vaginal gel formulations. All LSDFs were well tolerated in the mouse model. Following i.vag administration, all LSDFs boosted systemic CN54gp140-specific antibody responses in sub-cutaneously primed mice. Induction of CN54gp140-specific antibody responses in the female genital tract was evident. Of all the LSDFs the fastest releasing which was lyophilized Carbopol® gel elicited immune responses comparable to buffer instillation of antigen suggesting that rather than slower sustained release, initial high burst release from the LSDFs may suffice. The boosting of specific immune responses upon i.vag administration indicates that LSDFs are viable mucosal vaccine delivery modalities promoting antigen stability and facilitating intimate exposure of CN54gp140 to the mucosal-associated lymphoid tissue of the female genital tract.

The Effect of Liposome Encapsulation on the Pharmacokinetics of Recombinant Secretory Leukocyte Protease Inhibitor (rSLPI) Therapy after Local Delivery to a Guinea Pig Asthma Model

Inhaled recombinant Secretory Leukocyte Protease Inhibitor (rSLPI) has shown potential for treatment of inflammatory lung conditions. Rapid inactivation of rSLPI by cathepsin L (Cat L) and rapid clearance from the lungs have limited clinical efficacy. Encapsulation of rSLPI within 1,2-Dioleoyl-sn-Glycero-3-[Phospho-L-Serine]:Cholesterol liposomes (DOPS-rSLPI) protects rSLPI against Cat L inactivation in vitro. We aimed to determine the effect of liposomes on rSLPI pharmacokinetics and activity in vitro and after local delivery to the airways in vivo.

Oxidized Recombinant Human Growth Hormone That Maintains Conformational Integrity

Chemical degradations often induce changes in protein conformation and thus influence protein activity and protein stability in solutions. One difficulty in studying of chemical degradations on protein aqueous properties is to obtain sufficient amount of chemically degraded protein which is well characterized. Chemical degradation protocols that are often used may induce also conformation changes and aggregation of the protein. In this article we studied the effect of methionine oxidation on the conformation of recombinant human growth hormone (r-hGH). In literature it is reported that oxidation of methionine residues induces conformation changes on r-hGH. In our study, oxidation of r-hGH was performed by incubation with hydrogen peroxide under mild conditions. Mass spectrometry and chromatographic analysis revealed that oxidation with hydrogen peroxide resulted in more than 90% of oxidized r-hGH. By extensive spectroscopic characterizations no detectable change in conformation and aggregation of r-hGH after oxidation was found. In conclusion, mild oxidation conditions led to selective oxidation of the two more accessible methionine residues of r-hGH (Met(14) and Met(125)) and did not results in any conformation change of the protein. These findings prove that oxidation of human growth hormone does not influence protein conformation and demonstrate the importance of employing mild conditions during production of oxidized protein. (C) 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:110-122, 2011

Protection of cattle against a natural infection of Fasciola hepatica by vaccination with recombinant cathepsin L1 (rFhCL1)

The liver fluke, Fasciola hepatica causes liver fluke disease, or fasciolosis, in ruminants such as cattle and sheep. An effective vaccine against the helminth parasite is essential to reduce our reliance on anthelmintics, particularly in light of frequent reports of resistance to some frontline drugs. In our study, Friesian cattle (13 per group) were vaccinated with recombinant F. hepatica cathepsin L1 protease (rFhCL1) formulated in mineral-oil based adjuvants, Montanide (TM) ISA 70VG and ISA 206VG. Following vaccination the animals were exposed to fluke-contaminated pastures for 13 weeks. At slaughter, there was a significant reduction in fluke burden of 48.2% in the cattle in both vaccinated groups, relative to the control non-vaccinated group, at p

Evaluation of hepatic changes and local and systemic immune responses in goats immunized with recombinant Peroxiredoxin (Prx) and challenged with Fasciola hepatica

Protection against Fasciola hepatica in goats immunized with Peroxiredoxin (Prx) was assessed. The experimental trial consisted of three groups of seven animals: group 1 were unimmunized and uninfected, group 2 were immunized with adjuvant only and group 3 were immunized with recombinant Prx in adjuvant (immunized and infected). Immunization with Prx in Quil A adjuvant, group 3, induced a reduction in fluke burden of 33.04% when compared to adjuvant control, group 2, although this difference was not significant. The hepatic gross and microscopical morphometric study revealed lower damage in the Prx-immunized compared to group 2 (p

STIMULATION OF PHOSPHOLIPASE C-BETA(2) BY RECOMBINANT GUANINE-NUCLEOTIDE-BINDING PROTEIN BETA-GAMMA DIMERS PRODUCED IN A BACULOVIRUS/INSECT CELL EXPRESSION SYSTEM - REQUIREMENT OF GAMMA-SUBUNIT ISOPRENYLATION FOR STIMULATION OF PHOSPHOLIPASE-C

Recombinant wild-type beta(1) gamma(1) dimers of signal-transducing guanine nucleotide-binding proteins (G proteins) and beta(1) gamma 1 dimers carrying a mutation known to block gamma-subunit isoprenylation (beta(1) gamma(1)C71S) were expressed in baculovirus-infected insect cells. Both wild-type and mutant beta(1) gamma(1) dimers were found in soluble fractions of infected cells upon subcellular fractionation. Anion exchange chromatographic and metabolic-radiolabeling studies revealed that the soluble beta(1) gamma(1) preparation contained approximately equal amounts of non-isoprenylated and isoprenylated beta(1) gamma(1) dimers. Soluble wild-type and mutant beta(1) gamma(1) dimers and native beta(1) gamma(1) dimers purified from bovine retina were reconstituted with recombinant phospholipase C-beta(2). Only isoprenylated beta(1) gamma(1) dimers were capable of stimulating phospholipase C-beta(2). The results show that gamma-subunit isoprenylation and/or additional post-translational processing of the protein are required for beta gamma subunit stimulation of phospholipase C.

Development of liposome gel based formulations for intravaginal delivery of the recombinant HIV-1 envelope protein CN54gp140

Mucosally-administered vaccine strategies are widely investigated as a promising means of preventing HIV infection. This study describes the development of liposomal gel formulations, and novel lyophilised variants, comprising HIV-1 envelope glycoprotein, CN54gp140, encapsulated within neutral, positively charged or negatively charged liposomes. The CN54gp140 liposomes were evaluated for mean vesicle diameter, polydispersity, morphology, zeta potential and antigen encapsulation efficiency before being incorporated into hydroxyethyl cellulose (HEC) aqueous gel and subsequently lyophilised to produce a rod-shaped solid dosage form for practical vaginal application. The lyophilised liposome-HEC rods were evaluated for moisture content and redispersibility in simulated vaginal fluid. Since these rods are designed to revert to gel form following intravaginal application, mucoadhesive, mechanical (compressibility and hardness) and rheological properties of the reformed gels were evaluated. The liposomes exhibited good encapsulation efficiency and the gels demonstrated suitable mucoadhesive strength. The freeze-dried liposome-HEC formulations represent a novel formulation strategy that could offer potential as stable and practical dosage form.