Evaluation of suitability of two tools for the diagnosis of canine visceral leishmaniasis.

Background: Leishmaniasis still imposes a heavy burden on many health systems and remains a public health problem. Early diagnosis in dogs, which act as a major reservoir for the pathogen, is central. The intention of epidemiologic studies is to identify the disease early, allowing rapid intervention to reduce its effects.

Proteins-Based Nanoparticles for Benznidazole Enteric Delivery.

Chagas disease, caused by Trypanosoma cruzi (T. cruzi), affects millions worldwide, particularly in Latin America. Despite its prevalence, treatment options remain limited.

Validation of an immunochromatographic assay kit based on colored latex particles for the identification of the canine visceral leishmaniasis.

Visceral leishmaniasis is a zoonotic infectious disease with a severe impact on humans and animals. Infection is transmitted by phlebotomine sand flies. The dogs are main reservoir for human infection.

A lateral flow immunoassay based on colored latex particles for detection of canine visceral leishmaniasis.

Canine visceral leishmaniasis (CVL) is the major source of human visceral leishmaniasis. To control the spread of this disease, early and accurate detection of infected dogs is critical but challenging. The serological diagnosis of CVL remains problematic because there are no reliable commercially available tests.

Effect of Delivery Platforms Structure on the Epidermal Antigen Transport for Topical Vaccination.

Transdermal immunization is highly attractive because of the skin's accessibility and unique immunological characteristics. However, it remains a relatively unexplored route of administration because of the great difficulty of transporting antigens past the outermost layer of skin, the stratum corneum. In this article, the abilities of three poly( N-vinylcaprolactam) (PVCL)-based thermoresponsive assemblies-PVCL hydrogels and nanogels plus novel film forming PVCL/acrylic nanogels-to act as protein delivery systems were investigated.

Development of a simple and economical diagnostic test for canine leishmaniasis.

Visceral leishmaniasis is a public health problem worldwide. The early diagnosis in dogs is crucial, since they are an epidemiologically relevant reservoir of the disease. The aim of a field study is to early identify the disease allowing rapid intervention to reduce its effects.

Diagnosis of toxoplasmosis in pregnancy. Evaluation of latex-protein complexes by immnunoagglutination.

The aim of this work was to obtain a reagent based on latex particles for ruling out acute toxoplasmosis in pregnant women by immunoagglutination (IA). Latex-protein complexes (LPC) were previously synthesized coupling the recombinant protein of Toxoplasma gondii P22Ag and the homogenate of the parasite to latex particles with different size, chemical functionality and charge density. LPC were tested in IA assays against a panel of 72 pregnant women serum samples.

P35 and P22 Toxoplasma gondii antigens abbreviate regions to diagnose acquired toxoplasmosis during pregnancy: toward single-sample assays.

Background: P35 and P22 Toxoplasma gondii proteins are recognized by specific IgG at the early infection stage, making them ideal for acute toxoplasmosis pregnancy control. Both proteins have been studied to discriminate between acute and chronic toxoplasmosis. However, results were hardly comparable because different protein obtainment procedures led to different antigens, the reference panels used were not optimally typified, and avidity tests were either not performed or narrowly examined.

Immunoagglutination test to diagnose Chagas disease: comparison of different latex-antigen complexes.

Objective: To evaluate the diagnostic performance of novel latex-protein complexes obtained from different antigens of Trypanosoma cruzi through immunoagglutination test using a panel of T. cruzi-positive sera, leishmaniasis-positive sera and negative sera for both parasites.

Methods: Complexes' behaviour using total parasite homogenate (TPH), two simple recombinant proteins (RP1 and RP5) and two chimeric recombinant proteins (CP1 and CP2) was comparatively evaluated.

Latex-protein complexes from an acute phase recombinant antigen of Toxoplasma gondii for the diagnosis of recently acquired toxoplasmosis.

The synthesis and characterization of latex-protein complexes (LPC), from the acute phase recombinant antigen P35 (P35Ag) of Toxoplasma gondii and "core-shell" carboxylated or polystyrene (PS) latexes (of different sizes and charge densities) are considered, with the aim of producing immunoagglutination reagents able to detect recently acquired toxoplasmosis. Physical adsorption (PA) and chemical coupling (CC) of P35Ag onto latex particles at different pH were investigated. Greater amounts of adsorbed protein were obtained on PS latexes than on carboxylated latexes, indicating that hydrophobic forces govern the interactions between the protein and the particle surface.

Optimisation and standardisation of an immunoagglutination assay for the diagnosis of Trypanosoma cruzi infection based on latex-(recombinant antigen) complexes.

Objective: To determine the conditions under which the immunoagglutination assay to detect Chagas disease, obtained from a novel latex-(chimeric recombinant antigen) complex, shows greater discrimination between the responses of a positive control serum and a negative control serum.

Methods: The following variables were determined: (i) the sensitisation mechanism, (ii) the emulsifier employed for protein desorption, (iii) the reaction time, (iv) the ionic strength of the reaction medium, (v) the particle concentration, (vi) the presence of blocking agents, (vii) the presence of polyethyleneglycol as potentiator of reaction and (viii) the antigen and antibody concentrations. The search of optimal conditions was investigated by varying one variable at a time.

Synthesis of latex-antigen complexes from single and multiepitope recombinant proteins. Application in immunoagglutination assays for the diagnosis of Trypanosoma cruzi infection.

The physical adsorption and the chemical coupling of recombinant proteins of Trypanosoma cruzi onto polystyrene and core-shell carboxylated particles were respectively investigated with the ultimate aim of producing latex-protein complexes to be used in an immunoagglutination assay able to detect the Chagas disease. To this effect, two single proteins (RP1 and RP5) and a multiepitope protein derived from three antigenic peptides (CP2) were evaluated, and sensitizations were carried out at different pHs. The maximum physical adsorption was produced at pHs close to the protein isoelectric point (i.

Immunodiagnosis of Chagas disease: Synthesis of three latex-protein complexes containing different antigens of Trypanosoma cruzi.

This article describes the physical adsorption and the chemical coupling of 3 antigenic proteins of Trypanosoma cruzi onto polystyrene (PS) based latexes to be used as novel immunodiagnosis reagents for detecting the Chagas disease. The coupled proteins were a homogenate of T. cruzi, or a recombinant protein (either Ag36 or CP1).

Latex of immunodiagnosis for detecting the Chagas disease. I. Synthesis of the base carboxylated latex.

This article investigates the synthesis of two (monodisperse, carboxylated, and core-shell) latexes, through a batch and a semibatch emulsion copolymerizations of styrene (St) and methacrylic acid (MAA) onto polystyrene latex seeds. A mathematical model of the process was developed that predicts conversion, average particle size, and surface density of carboxyl groups. The model was adjusted to the batch reaction measurements, and then it was used in the design of the semibatch experiment.

Latex of immunodiagnosis for detecting the Chagas disease: II. Chemical coupling of antigen Ag36 onto carboxylated latexes.

A novel immunodiagnosis reagent for detecting the Chagas Disease was developed, by chemical coupling of antigen Ag36 of Trypanosoma cruzi onto two (carboxylated and core-shell) latexes. The coupling reactions involved the use of a carbodiimide intermediate. Bovine serum albumin (BSA) was used as a model protein for determining the appropriate conditions for its physical and chemical coupling.

Contamination by larger particles of two almost-uniform latices: analysis by combined dynamic light scattering and turbidimetry.

Multiangle dynamic light scattering (MDLS) and turbidimetry (T) were applied (both individually and combined) for determining the contamination by larger particles of two almost-uniform polystyrene (PS) latices. Latex 1 was synthesized in our laboratories, and it contained a main population diameter of 340 nm together with a small fraction of larger particles. This latex was used as the base material for producing an immunoassay kit.

Latex particle size distribution by dynamic light scattering: novel data processing for multiangle measurements.

Multiangle dynamic light scattering (DLS) provides a better estimate of particle size distributions (PSD) than single-angle DLS. However, multiangle data treatment requires appropriate weighting of each autocorrelation measurement prior to calculation of the PSD. The weighting coefficients may be directly obtained from (i).