scholarly journals Naturally acquired antibody response to a Plasmodium falciparum chimeric vaccine candidate GMZ2.6c and its components (MSP-3, GLURP, and Pfs48/45) in individuals living in Brazilian malaria-endemic areas

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Barbara Oliveira Baptista ◽  
Ana Beatriz Lopes de Souza ◽  
Evelyn Kety Pratt Riccio ◽  
Cesare Bianco-Junior ◽  
Paulo Renato Rivas Totino ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Antibody Response ◽  
Vaccine Candidate ◽  
Chimeric Protein ◽  
The State ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Multi Stage ◽  
Endemic Areas ◽  
Different Levels

Abstract Background The GMZ2.6c malaria vaccine candidate is a multi-stage Plasmodium falciparum chimeric protein which contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, a fusion protein of GLURP and MSP-3, that has been shown to be well tolerated, safe and immunogenic in clinical trials performed in a malaria-endemic area of Africa. However, there is no data available on the antigenicity or immunogenicity of GMZ2.6c in humans. Considering that circulating parasites can be genetically distinct in different malaria-endemic areas and that host genetic factors can influence the immune response to vaccine antigens, it is important to verify the antigenicity, immunogenicity and the possibility of associated protection in individuals living in malaria-endemic areas with different epidemiological scenarios. Herein, the profile of antibody response against GMZ2.6c and its components (MSP-3, GLURP and Pfs48/45) in residents of the Brazilian Amazon naturally exposed to malaria, in areas with different levels of transmission, was evaluated. Methods This study was performed using serum samples from 352 individuals from Cruzeiro do Sul and Mâncio Lima, in the state of Acre, and Guajará, in the state of Amazonas. Specific IgG, IgM, IgA and IgE antibodies and IgG subclasses were detected by Enzyme-Linked Immunosorbent Assay. Results The results showed that GMZ2.6c protein was widely recognized by naturally acquired antibodies from individuals of the Brazilian endemic areas with different levels of transmission. The higher prevalence of individuals with antibodies against GMZ2.6c when compared to its individual components may suggest an additive effect of GLURP, MSP-3, and Pfs48/45 when inserted in a same construct. Furthermore, naturally malaria-exposed individuals predominantly had IgG1 and IgG3 cytophilic anti-GMZ2.6c antibodies, an important fact considering that the acquisition of anti-malaria protective immunity results from a delicate balance between cytophilic/non-cytophilic antibodies. Interestingly, anti-GMZ2.6c antibodies seem to increase with exposure to malaria infection and may contribute to parasite immunity. Conclusions The data showed that GMZ2.6c protein is widely recognized by naturally acquired antibodies from individuals living in malaria-endemic areas in Brazil and that these may contribute to parasite immunity. These data highlight the importance of GMZ2.6c as a candidate for an anti-malarial vaccine.

scholarly journals C-Terminal Invariable Domain of VlsE Is Immunodominant but Its Antigenicity Is Scarcely Conserved among Strains of Lyme Disease Spirochetes

2001 ◽  
Vol 69 (5) ◽  
pp. 3224-3231 ◽  
Author(s):  
Fang Ting Liang ◽  
Lisa C. Bowers ◽  
Mario T. Philipp
Keyword(s):  
Lyme Disease ◽  
Antibody Response ◽  
Human Serum ◽  
Synthetic Peptide ◽  
Species Complex ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Variable Surface ◽  
Entire Sequence ◽  
Carboxyl Terminal

ABSTRACT VlsE, the variable surface antigen of Borrelia burgdorferi, contains two invariable domains located at the amino and carboxyl terminal ends, respectively, and a central variable domain. In this study, both immunogenicity and antigenic conservation of the C-terminal invariable domain were assessed. Mouse antiserum to a 51-mer synthetic peptide (Ct) which reproduced the entire sequence of the C-terminal invariable domain of VlsE from B. burgdorferi strain B31 was reacted on immunoblots with whole-cell lysates extracted from spirochetes of 12 strains from the B. burgdorferi sensu lato species complex. The antiserum recognized only VlsE from strain B31, indicating that epitopes of this domain differed among these strains. When Ct was used as enzyme-linked immunosorbent assay (ELISA) antigen, all of the seven monkeys and six mice that were infected with B31 spirochetes produced a strong antibody response to this peptide, indicating that the C-terminal invariable domain is immunodominant. None of 12 monkeys and only 11 of 26 mice that were infected with strains other than B31 produced a detectable anti-Ct response, indicating a limited antigenic conservation of this domain among these strains. Twenty-six of 33 dogs that were experimentally infected by tick inoculation were positive by the Ct ELISA, while only 5 of 18 serum samples from dogs clinically diagnosed with Lyme disease contained detectable anti-Ct antibody. Fifty-seven of 64 serum specimens that were collected from American patients with Lyme disease were positive by the Ct ELISA, while only 12 of 21 European samples contained detectable anti-Ct antibody. In contrast, antibody to the more conserved invariable region IR6 of VlsE was present in all of these dog and human serum samples.

scholarly journals Enzyme-Linked Immunosorbent Assay for Detection of Plasmodium falciparum Histidine-Rich Protein 2 in Blood, Plasma, and Serum

2008 ◽  
Vol 15 (6) ◽  
pp. 1012-1018 ◽  
Author(s):  
Carolyne M. Kifude ◽  
Halli G. Rajasekariah ◽  
David J. Sullivan ◽  
V. Ann Stewart ◽  
Evelina Angov ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Immunosorbent Assay ◽  
Whole Blood ◽  
Linear Range ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Target Concentration ◽  
Intervention Trials ◽  
Lower Limits ◽  
Asexual Cycle

ABSTRACT Microscopy, the gold standard for the detection and quantification of malaria parasites in blood, is in many aspects deficient for this purpose. The method is poorly reproducible and can be inaccurate because Plasmodium falciparum parasites sequester for a portion of each asexual cycle. Due to these deficiencies, biomarkers such as P. falciparum histidine-rich protein 2 (PfHRP2) are increasingly being used. In this study, we evaluated the use of a commercial PfHRP2 enzyme-linked immunosorbent assay (ELISA) kit with some procedural modifications. We determined the linear range of the assay, including the lower limits of detection and quantitation, using recombinant PfHRP2 (rPfHRP2). In 10 repeat experiments, the linear range of optical densities (ODs) at 450 to 650 nm was from 0.05 ± 0.002 to 2.28 ± 0.042, corresponding to 3.91 to 250 ng/ml of rPfHRP2. The coefficient of variation (CV) at each target concentration ranged from 1.93 to 8.07%. Using cultured parasites, we confirmed the linear range of ODs as well as the association between the PfHRP2 ELISA results and the microscopic parasite densities. For whole-blood samples spiked with cultured, washed, ring-stage-infected red blood cells (iRBCs), the linear range was 11.7 to 750 iRBCs/μl, with CVs of 0.29 to 7.56%. The same spiked samples evaluated by microscopists had similar sensitivities, but the CVs were unacceptably high (20.7 to 161.6%). Stock rPfHRP2 was stable through four freeze-thaw cycles (P < 0.05; paired t test). When different patient sample types at different concentrations within the linear range of the assay are compared, the recoveries of PfHRP2 from blood and serum were within ±20%, whereas the recoveries from plasma ranged between +35 and −41%. We conclude that PfHRP2 ELISA using whole-blood and serum samples is a suitable adjunct to microscopy and could ultimately benefit malaria intervention trials.

scholarly journals Decreased Serum Antibody Responses to RecombinantPneumocystisAntigens in HIV-Infected and Uninfected Current Smokers

2010 ◽  
Vol 18 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Kristina Crothers ◽  
Kieran R. Daly ◽  
David Rimland ◽  
Matthew Bidwell Goetz ◽  
Cynthia L. Gibert ◽  
...  
Keyword(s):  
Antibody Response ◽  
Serum Antibody ◽  
Antibody Responses ◽  
Surface Glycoprotein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chronic Obstructive ◽  
Tobit Regression ◽  
Serum Samples ◽  
Cross Sectional ◽  
Prospective Longitudinal

ABSTRACTSerologic studies can provide important insights into the epidemiology and transmission ofPneumocystis jirovecii. Exposure toP. jiroveciican be assessed by serum antibody responses to recombinant antigens from the major surface glycoprotein (MsgC), although factors that influence the magnitude of the antibody response are incompletely understood. We determined the magnitudes of antibody responses toP. jiroveciiin comparison to adenovirus and respiratory syncytial virus (RSV) in HIV-infected and uninfected patients and identified predictors associated with the magnitude of the response. We performed a cross-sectional analysis using serum samples and data from 153 HIV-positive and 92 HIV-negative subjects enrolled in a feasibility study of the Veterans Aging Cohort 5 Site Study (VACS 5). Antibodies were measured using an enzyme-linked immunosorbent assay (ELISA). Independent predictors of antibody responses were determined using multivariate Tobit regression models. The results showed that serum antibody responses toP. jiroveciiMsgC fragments were significantly and independently decreased in current smokers. Antibodies toP. jiroveciialso tended to be lower with chronic obstructive pulmonary disease (COPD), hazardous alcohol use, injection drug use, and HIV infection, although these results were not statistically significant. These results were specific toP. jiroveciiand did not correlate with adenovirus. Antibody responses to RSV were in the inverse direction. Thus, current smoking was independently associated with decreasedP. jiroveciiantibody responses. Whether smoking exerts an immunosuppressive effect that affects theP. jiroveciiantibody response, colonization, or subsequent risk for disease is unclear; prospective, longitudinal studies are needed to evaluate these findings further.

scholarly journals Solution structure of a Plasmodium falciparum AMA-1/MSP 1 chimeric protein vaccine candidate (PfCP-2.9) for malaria

2010 ◽  
Vol 9 (1) ◽  
pp. 76 ◽  
Author(s):  
Heng Peng ◽  
Yunfei Hu ◽  
Aiguo Zhou ◽  
Changwen Jin ◽  
Weiqing Pan
Keyword(s):  
Plasmodium Falciparum ◽  
Solution Structure ◽  
Vaccine Candidate ◽  
Chimeric Protein ◽  
Protein Vaccine

scholarly journals Serological markers for hepatitis a among captive and free-living wild mammals in the State of Pará, Brazil

2021 ◽  
Vol 42 (3Supl1) ◽  
pp. 1635-1646
Author(s):  
Marcella Katheryne Marques Bernal ◽  
◽  
Alex Júnior Souza de Souza ◽  
Heloisa Marceliano Nunes ◽  
Andreza Pinheiro Malheiros ◽  
...  
Keyword(s):  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Animal Health ◽  
The State ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Free Living ◽  
Wild Mammals ◽  
Basic Sanitation ◽  
The Impact

The hepatitis A virus (HAV, Hepatovirus A) in humans has a relevant impact on public health, especially in geographic regions with poor basic sanitation, such as the Brazilian Amazon. Isolates related to hepatoviruses have been described in non human primates, chiropterans, marsupials, rodents, marmots, shrews, and terrestrial hedgehogs. However, the circulation of these viruses in the Amazonian mammal fauna remains unexplored. This study aimed to evaluate the prevalence of antibodies against this hepatovirus in captive and free-living wild mammals belonging to the orders Didelphimorphia, Primates, Carnivora, and Artiodactyla. Serum samples from 71 animals, from three municipalities in the State of Pará (Belém, Santarém, and Capitão-Poço) were tested for total anti-HAV and anti-HAV IgM through enzyme-linked immunosorbent assay (ELISA). Total anti-HAV antibodies were detected in 29.5% (21/71) of non-human primates, 8.4% (6/71) of carnivores, and 5.6% (4/71) of didelphos. All tayassuidos 0% (0/2) were seronegative. Anti-HAV IgM antibodies were not detected in any of the samples tested. The highest total anti-HAV seropositivity in the municipalities studied was in Santarém with 54.24% (12/22), followed by Capitão Poço with 50% (15/30), and then Belém with 21.05% (4/19). Among the seropositive animals, animals kept in exposure cages showed 43.9% (18/41), quarantined animals with 60% (9/15), and free-living animals with 26.6% (4/15). The serological results indicated a profile of previous exposure to hepatovirus among these animals. Therefore, additional studies to characterize HAV-related viruses in captive and free living wild animals need to be conducted to better understand the impact of the circulation of this virus on human and animal health.

scholarly journals Characterization of a Borrelia burgdorferi VlsE Invariable Region Useful in Canine Lyme Disease Serodiagnosis by Enzyme-Linked Immunosorbent Assay

2000 ◽  
Vol 38 (11) ◽  
pp. 4160-4166 ◽  
Author(s):  
Fang Ting Liang ◽  
Richard H. Jacobson ◽  
Reinhard K. Straubinger ◽  
Amy Grooters ◽  
Mario T. Philipp
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Antibody Response ◽  
Immunosorbent Assay ◽  
Protein A ◽  
Immunoblot Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Entire Study ◽  
Variable Surface

Sera collected from dogs experimentally infected withBorrelia burgdorferi by tick inoculation were analyzed for an antibody response to each of the six invariable regions (IRs; i.e., IR1 to IR6) of VlsE, the variable surface antigen of B. burgdorferi. Six synthetic peptides (C1 to C6), which reproduced the six IR sequences were used as peptide-based, enzyme-linked immunosorbent assay (ELISA) antigens. Two IRs, IR2 and IR6, were found to be immunodominant. Studies with serially collected serum samples from experimentally infected dogs revealed that the antibody response to IR6 appears earlier and is stronger than that to IR2. Thus, the IR6 sequence alone appeared to be sufficient for serodiagnosis. When C6 alone was used as antigen, the peptide-based ELISA was positive in 7 of 23 dogs (30%) as early as 3 weeks postinfection. All dogs (n = 33) became strongly positive 1 or 2 weeks later, and this response persisted for the entire study, which lasted for 69 weeks. Of 55 sera submitted by veterinarians from dogs suspected of having Lyme disease, 19 were also positive by the C6 ELISA, compared to 20 positives detected by immunoblot analysis using cultured B. burgdorferi lysates as antigen. The sensitivity of using C2 and C6 together for detecting specific antibody in both experimentally infected and clinically diagnosed dogs was not better than sensitivity with C6 alone, confirming that C6 suffices as a diagnostic probe. Moreover, the C6 ELISA yielded 100% specificity with serum samples collected from 70 healthy dogs, 14 dogs with infections other than B. burgdorferi, and 15 animals vaccinated with either outer surface protein A, whole-spirochete vaccines, or the common puppy-vaccines. Therefore, this C6 ELISA was both sensitive and specific for the serodiagnosis of canine Lyme disease and could be used with vaccinated dogs.

An ELISA kit with two detection modes for the diagnosis of lymphatic filariasis

2014 ◽  
Vol 89 (5) ◽  
pp. 552-558 ◽  
Author(s):  
S. Wongkamchai ◽  
W. Satimai ◽  
S. Loymek ◽  
H. Nochot ◽  
J.J. Boitano
Keyword(s):  
Lymphatic Filariasis ◽  
Low Cost ◽  
Kappa Statistic ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Laboratory Equipment ◽  
Elisa Kit ◽  
Naked Eye ◽  
Test Kit ◽  
Endemic Areas

AbstractThe aim of this study was to develop a low-cost antifilarial immunoglobulin (Ig) G4 detection kit for the diagnosis of lymphatic filariasis. The kit was designed to be used by minimally trained personnel without the constraints of expensive laboratory equipment. We provide a description of the development and validation of a single-serum-dilution based enzyme-linked immunosorbent assay (ELISA) kit with ready-to-use reagents for measuring antifilarial IgG4 antibodies. The kit was tested on residents in Brugia malayi-endemic areas in southern Thailand. Detection was performed by naked-eye observation of the resultant colour of the immunological reactivity. The coefficient of variation (CV) was used to assess the reproducibility of the results. Long-term stability was measured over a 6-month period. Sensitivity of the test kit was 97% when compared with microfilariae detection in thick blood smears. Specificity was 98.7% based on the sera of 57 patients living outside the endemic areas who were infected with other parasites and 100 parasite-free subjects. All positive CVs were < 10%. The test kit was remarkably stable over 6 months. Field validation was performed by the detection of antifilarial IgG4 in 4365 serum samples collected from residents of brugian filariasis-endemic areas and compared with outcome colours of the test samples by the naked eye. Subsequent ELISA evaluation of these results using an ELISA reader indicated high agreement by the kappa statistic. These results demonstrate that the test kit is efficient and useful for public health laboratories as an alternative tool for the diagnosis of lymphatic filarial infection.

scholarly journals Use of Moraxella catarrhalis Lipooligosaccharide Mutants To Identify Specific Oligosaccharide Epitopes Recognized by Human Serum Antibodies

2009 ◽  
Vol 77 (10) ◽  
pp. 4548-4558 ◽  
Author(s):  
Johanna M. Schwingel ◽  
Katie J. Edwards ◽  
Andrew D. Cox ◽  
Hussein Masoud ◽  
James C. Richards ◽  
...  
Keyword(s):  
Immune Response ◽  
Antibody Response ◽  
Human Serum ◽  
Moraxella Catarrhalis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Antibody ◽  
Serum Antibodies ◽  
Serum Samples ◽  
Carbohydrate Epitopes ◽  
Tract Infections

ABSTRACT Moraxella catarrhalis is a causative agent of otitis media in children and lower respiratory tract infections in adults suffering from chronic obstructive pulmonary disease (COPD). This strict human pathogen continues to be a significant cause of disease in this broad spectrum of patients because there is no available vaccine. Although numerous putative vaccine antigens have been described, little is known about the human immune response to M. catarrhalis infection in vivo. Human serum antibodies are directed at a number of surface proteins, and lipooligosaccharides (LOS) and detoxified LOS may be an effective immunogen in mice. In this study, we used a specific LOS-based enzyme-linked immunosorbent assay (ELISA), containing the three major M. catarrhalis serotypes together with a complete series of truncated LOS mutants, to detect the development of new antibodies to specific regions of the oligosaccharide molecule. We compared serum samples from COPD patients who had recently cleared an M. catarrhalis infection to serum samples collected prior to their infection. Variability in the antibody response to LOS was observed, as some patients developed serotype-specific antibodies, others developed antibodies to the LOS of each serotype, others developed broadly cross-reactive antibodies, and some did not develop new antibodies. These newly developed human antibodies are directed at both side chains and core structures in the LOS molecule. This LOS-based ELISA can be used to dissect the human antibody response to both internal and external carbohydrate epitopes, thus providing a better understanding of the humoral immune response to M. catarrhalis LOS epitopes developed during natural infection.

Sign in / Sign up

Export Citation Format

Share Document