Bibliographic Synthesis of Sero-Epidemiological Studies on Brucellosis in Domestic Ruminants (Cattle, Sheep and Goats) in Cameroon

Brucellosis is a neglected zoonosis in Cameroon but it remains enzootic in some agro-ecological zones of the country. This review aims to describe the current status of this disease in domestic ruminants in Cameroon. In order to know the current status of this disease, a systematic and synthetic review was conducted on brucellosis in domestic ruminants in Cameroon. Different types of studies with serological results were reported and considered. A total of 16 studies from 1980 to 2020 were included in this synthetic review of the literature. Most of the studies were cross-sectional descriptive studies (p = 0.12). However, there were also studies with simplified survey methods, modelling approaches, stratified non-probabilistic and probabilistic surveys. 5095 cases of brucellosis infection were identified in the literature, for which the laboratory diagnosis allowed confirmation of brucellosis in the different species (indirect or direct Elisa in the majority of studies (41%), followed by rose Bengal (26%)). In most cases cattle represent 80% of the most studied species. Associated with this, the northern part of Cameroon was the preferred study area at 70% followed by the west (27%) and the south (3%). The biological material of choice for the studies was serum (75%). In addition, other biological materials (15%) were used. This systematic review has identified the tools used over the last 40 years to diagnose brucella infection in ruminants in Cameroon. However, it highlights the need for continuous monitoring of the spatio-temporal evolution of abortive microorganisms on farms.

mAb Das-1 recognizes 3’-Sulfated Lewis A/C, which is aberrantly expressed during metaplastic and oncogenic transformation of several gastrointestinal Epithelia

Introduction Multiple previous studies have shown the monoclonal antibody Das-1 (formerly called 7E12H12) is specifically reactive towards metaplastic and carcinomatous lesions in multiple organs of the gastrointestinal system (e.g. Barrett’s esophagus, intestinal-type metaplasia of the stomach, gastric adenocarcinoma, high-grade pancreatic intraepithelial neoplasm, and pancreatic ductal adenocarcinoma) as well as in other organs (bladder and lung carcinomas). Beyond being a useful biomarker in tissue, mAb Das-1 has recently proven to be more accurate than current paradigms for identifying cysts harboring advanced neoplasia. Though this antibody has been used extensively for clinical, basic science, and translational applications for decades, its epitope has remained elusive. Methods In this study, we chemically deglycosylated a standard source of antigen, which resulted in near complete loss of the signal as measured by western blot analysis. The epitope recognized by mAb Das-1 was determined by affinity to a comprehensive glycan array and validated by inhibition of a direct ELISA. Results The epitope recognized by mAb Das-1 is 3’-Sulfo-Lewis A/C (3’-Sulfo-LeA/C). 3’-Sulfo-LeA/C is broadly reexpressed across numerous GI epithelia and elsewhere during metaplastic and carcinomatous transformation. Discussion 3’-Sulfo-LeA/C is a clinically important antigen that can be detected both intracellularly in tissue using immunohistochemistry and extracellularly in cyst fluid and serum by ELISA. The results open new avenues for tumorigenic risk stratification of various gastrointestinal lesions.

Population-level seropositivity trend for SARS-Cov-2 in Rio Grande do Sul, Brazil

OBJECTIVE: To describe the evolution of seropositivity in the State of Rio Grande do Sul, Brazil, through 10 consecutive surveys conducted between April 2020 and April 2021. METHODS: Nine cities covering all regions of the State were studied, 500 households in each city. One resident in each household was randomly selected for testing. In survey rounds 1–8 we used the rapid WONDFO SARS-CoV-2 Antibody Test (Wondfo Biotech Co., Guangzhou, China). In rounds 9–10, we used a direct ELISA test that identifies IgG to the viral S protein (S-UFRJ). In terms of social distancing, individuals were asked three questions, from which we generated an exposure score using principal components analysis. RESULTS: Antibody prevalence in early April 2020 was 0.07%, increasing to 10.0% in February 2021, and to 18.2% in April 2021. In round 10, self-reported whites showed the lowest seroprevalence (17.3%), while indigenous individuals presented the highest (44.4%). Seropositivity increased by 40% when comparing the most with the least exposed. CONCLUSIONS: The proportion of the population already infected by SARS-Cov-2 in the state is still far from any perspective of herd immunity and the infection affects population groups in very different levels.

Development of a Dendrimeric Peptide-Based Approach for the Differentiation of Animals Vaccinated with FlagT4G against Classical Swine Fever from Infected Pigs

Classical swine fever virus (CSFV) causes a viral disease of high epidemiological and economical significance that affects domestic and wild swine. Control of the disease in endemic countries is based on live-attenuated vaccines (LAVs) that induce an early protective immune response against highly virulent CSFV strains. The main disadvantage of these currently available LAVs is the lack of serological techniques to differentiate between vaccinated and infected animals (DIVA concept). Here, we describe the development of the FlagDIVA test, a serological diagnostic tool allowing for the differentiation between animals vaccinated with the FlagT4G candidate and those infected with CSFV field strains. The FlagDIVA test is a direct ELISA based on a dendrimeric peptide construct displaying a conserved epitope of CSFV structural protein E2. Although FlagDIVA detected anti-CSFV anti-bodies in infected animals, it did not recognize the antibody response of FlagT4G-vaccinated animals. Therefore, the FlagDIVA test constitutes a valuable accessory DIVA tool in implementing vaccination with the FlagT4G candidate.

Immunohistochemical diagnosis of onychomycosis by monoclonal antibodies detection of dermatophyte T. rubrum

Introduction/Objective Onychomycosis is one of the most common nail infection disorders, caused predominantly by T. rubrum. Currently, PAS stain is the gold standard for histological onychomycosis detection. However, it does not differentiate between the types of fungi. In addition, PAS stains will only provide a positive or negative result. This leaves physicians to prescribe medications that may be ineffective in treating the root cause of the infection. By discerning the causative specie, physicians can provide a more targeted and effective anti-fungal therapy. A novel monoclonal antibody can be utilized to improve histological findings of T. rubrum. Our study takes a step forward to bring the monoclonal antibody into histological application. We have developed a new monoclonal antibody stain which binds to T. rubrum in vitro. For our project, we will perform in vivo staining on clinical nail samples using the novel monoclonal antibody. Developing a new applicable technique will benefit patients with onychomycosis as well as promote research in targeted identification of other infectious pathologies. Methods/Case Report Data from Bach Dx’s collaboration demonstrate isolation and validation of mice monoclonal antibody candidates for T. rubrum. Isotype IgG1/kappa 17B6 had the highest binding pair signal to the analyte. Direct ELISA of 17B6.1E3 shows immunoreactivity to T. rubrum. HRP and AP conjugates to 17B6 mice monoclonal antibody are produced (Rockland Immunochemicals Inc. Gilbertsville, PA). Histology slides analyzed for routine onychomycosis analysis at Bach Diagnostics are subject to secondary analysis. 220 retrospective, unstained nail slides from 55 patients will be stained using the 17B6 stains. 40 patients were known to have tested for onychomycosis caused by T. rubrum, 5 by Candida albicans, 5 by T. interdigitale, and 5 tested negative. All samples were confirmed by histology and molecular tests. H&E, PAS, and naked antibody stains will serve as controls. HRP and AP conjugated 17B6 monoclonal antibody stains will be optimized to Quantum Hdx (StatLab Lodi, CA) on July 12th, 2021 when the stains are scheduled to arrive. Images will be captured by light microscopy, and analyzed quantitatively and qualitatively. Results (if a Case Study enter NA) We hope to show preferential staining of antibody stains to positive T. rubrum cases by end of July 2021. Conclusion Conclusion pending based on results.

Local Ancestry to Identify Selection in Response to Trypanosome Infection in Baoulé x Zebu Crossbred Cattle in Burkina Faso

The genomes of crossbred (admixed) individuals are a mosaic of ancestral haplotypes formed by recombination in each generation. The proportion of these ancestral haplotypes in certain genomic regions can be responsible for either susceptibility or tolerance against pathogens, and for performances in production traits. Using a medium-density genomic marker panel from the Illumina Bovine SNP50 BeadChip, we estimated individual admixture proportions for Baoulé x Zebu crossbred cattle in Burkina Faso, which were tested for trypanosome infection by direct ELISA from blood samples. Furthermore, we calculated local ancestry deviation from average for each SNP across 29 autosomes to identify potential regions under selection in the trypanotolerant Baoulé cattle and their crossbreds. We identified significant deviation from the local average ancestry (above 5 and 10% genome-wide thresholds) on chromosomes 8 and 19 in the positive animals, while the negative ones showed higher deviation on chromosomes 6, 19, 21, and 22. Some candidate genes on chromosome 6 (PDGFRA) and chromosome 19 (CDC6) have been found associated to trypanotolerance in West African taurines. Screening for FST outliers in trypanosome positive/negative animals we detected seven variants putatively under selection. Finally, we identified a minimum set of highly ancestry informative markers for routine admixture testing. The results of this study contribute to a better understanding of the genetic basis of trypanotolerance in Baoulé cattle and their crossbreeds. Furthermore, we provide a small informative marker set to monitor admixture in this valuable indigenous breed. As such, our results are important for conserving the genetic uniqueness and trypanotolerance of Baoulé cattle, as well as for the improvement of Baoulé and Zebu crossbreds in specific community-based breeding programs.

Deteksi Level Antibodi Pada Serum Darah Anjing Kintamani Pasca Vaksinasi Rabies dengan Direct ELISA

The success of rabies vaccination is characterized by the growth of seropositive antibody titers (?0.5 IU) after vaccination. One of the tests conducted to monitor antibody growth is ELISA (Enzyme Linked Immunosorbent Assay). This study aimed to determine the effect of different vaccine doses on the growth of rabies antibodies in kintamani dogs. The study was conducted using an experimental method with a study design using 2 variables, namely the difference in vaccine doses (0.5 and 0.75 cc) and the times of blood collection (1, 2 and 3 months after vaccination). Each vaccine dose was given to three kintamani dogs. Antibodies were measured using ELISA and data were analyzed with paired sample t-test between the treatment dose of 0.75 cc and 0.5 cc at months 1.2 and 3 after vaccination. The results showed that at first month the antibody titer were 2,12 IU at a dose of 0.75 cc and 3.72 IU at a dose of 0.5 cc. At second months, antibody titers were 7.74 IU (0.75 cc dose) and 10.85 IU (0.5 cc dose), while at third month, antibody titers were 5.73 IU (0.75 cc) and 9.00 IU (0.5 cc). Vaccine doses administered produce antibody titer levels that did not differ significantly between 0.75 cc and 0.5 cc doses. Keyword: Antibody, ELISA, Kintamani Dog, Rabies

3'-Sulfated Lewis A is a Biomarker for Metaplastic and Oncogenic Transformation of Several Gastrointestinal Epithelia

Introduction: Multiple previous studies have shown the monoclonal antibody Das-1 (formerly called 7E12H12) specifically recognizes metaplastic and carcinomatous lesions in multiple organs of the gastrointestinal system (e.g. Barrett's esophagus, intestinal-type metaplasia of the stomach, gastric adenocarcinoma, high-grade pancreatic intraepithelial neoplasm, and pancreatic ductal adenocarcinoma) as well as in other organs (bladder and lung carcinomas). Beyond being a useful biomarker in tissue, mAb Das-1 has recently proven to be more accurate than current paradigms for identifying cysts harboring advanced neoplasia. Though this antibody has been used extensively for clinical, basic science, and translational applications for decades, its epitope has remained elusive. Methods: In this study, we chemically deglycosylated a standard source of antigen, which resulted in near complete loss of the signal as measured by western blot analysis. The epitope recognized by mAb Das-1 was determined by affinity to a comprehensive glycan array and validated by inhibition of a direct ELISA. Results: The epitope recognized by mAb Das-1 is 3'-Sulfo-Lewis A (3'-Sulfo-LeA). 3'-Sulfo-LeA is broadly reexpressed across numerous GI epithelia and elsewhere only after metaplastic and carcinomatous transformation. Discussion: 3'-Sulfo-LeA is a clinically important antigen that can be detected both intracellularly in tissue using immunohistochemistry and extracellularly in cyst fluid and serum by ELISA. The results open new avenues for tumorigenic risk stratification of various gastrointestinal lesions.

Survey of Commercial Food Products for Detection of Walnut (Juglans regia) by Two ELISA Methods and Real Time PCR

Labeling of food allergens in accordance with legal regulations is important to protect the health of allergic consumers. The requirements for detecting allergens in foods involve adequate specificity and sensitivity to identify very small amounts of the target allergens in complex food matrices and processed foods. In this work, one hundred commercial samples were analyzed for walnut detection using three different methods: a sandwich enzyme-linked immunosorbent assay (ELISA) kit based on polyclonal antibodies, a direct ELISA using a recombinant multimeric scFv, and a real time PCR. The most sensitive method was real time PCR followed by sandwich ELISA kit and multimeric scFv ELISA. There was agreement between the three methods for walnut detection in commercial products, except for some heat-treated samples or those that contained pecan. The walnut ELISA kit was less affected by sample processing than was the multimeric scFv ELISA, but there was cross-reactivity with pecan, producing some false positives that must be confirmed by real time PCR. According to the results obtained, 7.0 to 12.6% of samples (depending on the analytical method) contained walnut but did not declare it, confirming there is a risk for allergic consumers. Moreover, there was one sample (3.7%) labelled as containing walnut but that tested negative for this tree nut. Genetic and immunoenzymatic techniques offer complementary approaches to develop a reliable verification for walnut allergen labeling.

POLYCLONAL ANTIBODIES AGAINST HUMAN PLASMINOGEN: PURIFICATION, CHARACTERIZATION AND APPLICATION

The plasminogen/plasmin system plays a crucial role in fibrinolysis and regulation of cell functions in a wide range of normal and pathological processes. Investigation of plasminogen/plasmin functions requires the availability of well-characterized and effective molecular tools, such as antibodies. In the present work, the isolation and characterization of rabbit polyclonal antibodies against human plasminogen are described and approaches for the identification of plasminogen and its fragments using the purified antibodies are demonstrated. For the antibodies isolation, standard animal immunization and blood collection procedures, serum isolation, protein salting out and affinity chromatography were performed. For the antibodies characterization and application, the following methods were used: enzyme linked immunoassay (ELISA), Western blotting, FITC-protein conjugation, flow cytometry and spectrofluorometry. The obtained polyclonal rabbit anti-human plasminogen antibodies interacted with human Glu- and Lys-plasminogen, kringles 1-3 and 1-4 of plasminogen, mini-plasminogen, the heavy and light chain of plasmin. We propose the application of anti-plasminogen antibodies for the direct ELISA, Western blot analysis, and for flow cytometry and spectrofluorometric analysis of plasminogen binding with cells. The obtained anti-plasminogen antibodies are promising tools for the investigation of plasminogen/plasmin system functions, either fibrinolytic or signaling.