scholarly journals Acute Plasmodium chabaudi chabaudi Malaria Infection Induces Antibodies Which Bind to the Surfaces of Parasitized Erythrocytes and Promote Their Phagocytosis by Macrophages In Vitro

1998 ◽  
Vol 66 (9) ◽  
pp. 4080-4086 ◽  
Author(s):  
Maria M. Mota ◽  
K. Neil Brown ◽  
Anthony A. Holder ◽  
William Jarra
Keyword(s):  
Parasite Clearance ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Activity ◽  
Parasite Line ◽  
Primary Role ◽  
Plasmodium Chabaudi ◽  
Species Specific ◽  
Cellular Immune ◽  
Variant Line

ABSTRACT CBA/Ca mice infected with 5 × 104 Plasmodium chabaudi chabaudi AS-parasitized erythrocytes experience acute but self-limiting infections of relatively short duration. Parasitemia peaks (∼40% infected erythrocytes) on day 10 or 11 and is then partially resolved over the ensuing 5 to 6 days, a period referred to as crisis. How humoral and cellular immune mechanisms contribute to parasite killing and/or clearance during crisis is controversial. Humoral immunity might be parasite variant, line, or species specific, while cellular immune responses would be relatively less specific. For P. c. chabaudi AS, parasite clearance is largely species and line specific during this time, which suggests a primary role for antibody activity. Accordingly, acute-phase plasma (APP; taken fromP. c. chabaudi AS-infected mice at day 11 or 12 postinfection) was examined for the presence of parasite-specific antibody activity by enzyme-linked immunosorbent assay. Antibody binding to the surface of intact, live parasitized erythrocytes, particularly those containing mature (trophozoite and schizont) parasites, was demonstrated by immunofluorescence in APP and the immunoglobulin G (IgG)-containing fraction thereof. Unfractionated APP (from P. c. chabaudi AS-infected mice), as well as its IgG fraction, specifically mediated the opsonization and internalization of P. c. chabaudi AS-parasitized erythrocytes by macrophages in vitro. APP from another parasite line (P. c. chabaudi CB) did not mediate the same effect against P. c. chabaudi AS-parasitized erythrocytes. These results, which may represent one mechanism of parasite removal during crisis, are discussed in relation to the parasite variant, line, and species specificity of parasite clearance during this time.

Tandem antioxidant enzymes confer synergistic protective responses in experimental filariasis

2013 ◽  
Vol 88 (4) ◽  
pp. 402-410 ◽  
Author(s):  
P.R. Prince ◽  
J. Madhumathi ◽  
G. Anugraha ◽  
P.J. Jeyaprita ◽  
M.V.R. Reddy ◽  
...  
Keyword(s):  
Immune Responses ◽  
Redox Regulation ◽  
Protective Efficacy ◽  
Wuchereria Bancrofti ◽  
Parasite Clearance ◽  
Cross Reactivity ◽  
Host Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Helminth Parasites ◽  
Cellular Immune

AbstractHelminth parasites use antioxidant defence strategies for survival during oxidative stress due to free radicals in the host. Accordingly, tissue-dwelling filarial parasites counteract host responses by releasing a number of antioxidants. Targeting these redox regulation proteins together, would facilitate effective parasite clearance. Here, we report the combined effect of protective immune responses trigged by recombinant Wuchereria bancrofti thioredoxin (WbTRX) and thioredoxin peroxidase (WbTPX) in an experimental filarial model. The expression of WbTRX and WbTPX in different stages of the parasite and their cross-reactivity were analysed by enzyme-linked immunosorbent assay (ELISA). The immunogenicity of recombinant proteins and their protective efficacy were studied in animal models when immunized in single or cocktail mode. The antigens showed cross-reactive epitopes and induced high humoral and cellular immune responses in mice. Further, parasite challenge against Brugia malayi L3 larvae in Mastomyscoucha conferred significant protection of 57% and 62% against WbTRX and WbTPX respectively. The efficacy of L3 clearance was significantly higher (71%) (P <  0.001) when the antigens were immunized together, showing a synergistic effect in multiple-mode vaccination. Hence, the study suggests WbTRX and WbTPX to be attractive vaccine candidates when immunized together and provides a tandem block for parasite elimination in the control of lymphatic filariasis.

scholarly journals Antibody Recognition of Rodent Malaria Parasite Antigens Exposed at the Infected Erythrocyte Surface: Specificity of Immunity Generated in Hyperimmune Mice

2001 ◽  
Vol 69 (4) ◽  
pp. 2535-2541 ◽  
Author(s):  
Maria M. Mota ◽  
K. Neil Brown ◽  
Virgilio E. Do Rosário ◽  
Anthony A. Holder ◽  
William Jarra
Keyword(s):  
Malaria Parasite ◽  
Inbred Mice ◽  
Antibody Activity ◽  
Parasite Line ◽  
Rodent Malaria Parasite ◽  
Hyperimmune Serum ◽  
Rodent Malaria ◽  
Antibody Recognition ◽  
The Face ◽  
Species Specific

ABSTRACT In regions where malaria is endemic, inhabitants remain susceptible to repeated reinfection as they develop and maintain clinical immunity. This immunity includes responses to surface-exposed antigens onPlasmodium sp.-infected erythrocytes. Some of these parasite-encoded antigens may be diverse and phenotypically variable, and the ability to respond to this diversity and variability is an important component of acquired immunity. Characterizing the relative specificities of antibody responses during the acquisition of immunity and in hyperimmune individuals is thus an important adjunct to vaccine research. This is logistically difficult to do in the field but is relatively easily carried out in animal models. Infections in inbred mice with rodent malaria parasite Plasmodium chabaudi chabaudi AS represent a good model for Plasmodium falciparum in humans. This model has been used in the present study in a comparative analysis of cross-reactive and specific immune responses in rodent malaria. CBA/Ca mice were rendered hyperimmune toP. chabaudi chabaudi (AS or CB lines) or Plasmodium berghei (KSP-11 line) by repeated infection with homologous parasites. Serum from P. chabaudi chabaudi AS hyperimmune mice reacted with antigens released from disrupted P. chabaudi chabaudi AS-infected erythrocytes, but P. chabaudi chabaudi CB and P. berghei KSP-11 hyperimmune serum also contained cross-reactive antibodies to these antigens. However, antibody activity directed against antigens exposed at the surfaces of intact P. chabaudi chabaudi-infected erythrocytes was mainly parasite species specific and, to a lesser extent, parasite line specific. Importantly, this response included opsonizing antibodies, which bound to infected erythrocytes, leading to their phagocytosis and destruction by macrophages. The results are discussed in the context of the role that antibodies to both variable and invariant antigens may play in protective immunity in the face of continuous susceptibility to reinfection.

scholarly journals Immunogenicity of Quadrivalent HPV Vaccine in Adolescent Ghanaian Girls 36 Months After Vaccination

2021 ◽  
Author(s):  
Emmanuel Timmy Donkoh ◽  
Edward Tieru Dassah ◽  
Ellis Owusu-Dabo
Keyword(s):  
Adolescent Girls ◽  
Immunoglobulin G ◽  
Hpv Vaccine ◽  
Quadrivalent Vaccine ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Activity ◽  
Primary Role ◽  
Hpv 16 ◽  
Hpv 18

Abstract Introduction Available human papillomavirus (HPV) vaccines could have an important primary role in cervical cancer prevention once their long-term immunogenicity and safety are evaluated at the population level. The aim of this study was to optimize an assay to be used in evaluating the long-term durability of HPV vaccine response following a pilot vaccination of adolescent girls in Ghana. Methods A rapid, high-throughput, indirect enzyme-linked immunosorbent assay (ELISA) was evaluated for the detection and quantitation of anti-HPV L1 (late expression protein: types 6, 11, 16 and 18) immunoglobulin G (IgG) in human serum (n = 89). The performance of the assay was evaluated using serum collected from a cohort of pre-adolescent girls (n = 49) previously vaccinated with a quadrivalent vaccine and non-immune serum obtained from age-matched controls (n = 40). Results The seroprevalence of anti-HPV IgG antibodies was significantly higher among vaccinated than unvaccinated girls for both HPV − 16 (63.3% vs. 12.5%; p < 0.001) and HPV − 18 (34.7% vs. 20.0%; p = 0.042), respectively. Thirty-six months after receiving the third dose of vaccine, significantly higher mean anti–HPV-16 (0.618 vs. 0.145), anti–HPV-18 (0.323 vs. 0.309), and anti–HPV-6 (1.371 vs. 0.981) antibody levels were measured, compared to unvaccinated girls (all p < 0.05). A correlation between optical density and antibody activity indicated assay sensitivity to increasing levels of antibody activity. Conclusion We have successfully developed and implemented a robust and sensitive assay for the evaluation of antibody responses among immunized adolescent girls for monitoring future large-scale HPV vaccination studies in low-income settings. Our results demonstrated greater immunoglobulin G antibody activity within serum drawn from adolescent girls immunized 36 months prior.

scholarly journals Immunogenicity of trimetric spike protein associated to Poly(I:C) plus Alum

2021 ◽  
Author(s):  
Julio dos Santos ◽  
Luan Firmino Cruz ◽  
Alessandra Marcia da Fonseca-Martins ◽  
Diogo Oliveira Maciel ◽  
Gustavo Guadagnini Perez ◽  
...  
Keyword(s):  
B Cells ◽  
Vaccination Strategy ◽  
Lavage Fluid ◽  
Neutralization Assay ◽  
Spike Protein ◽  
Poly I:C ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cellular Immune ◽  
The Impact

The SARS-CoV-2 pandemic has had a social and economic impact worldwide, and vaccination is an efficient strategy for diminishing those damages. New adjuvant formulations are required for the high vaccine demands, especially adjuvant formulations that induce a Th1 phenotype. Herein we assess a vaccination strategy using a combination of Alum and polyinosinic:polycytidylic acid (Poly(I:C)) adjuvants plus the SARS-CoV-2 spike protein in a prefusion trimeric conformation by an intradermal (ID) route. We found high levels of IgG anti-spike antibodies in the serum by enzyme linked immunosorbent assay (ELISA) and high neutralizing titers against SARS-CoV-2 in vitro by neutralization assay, after one or two boosts. By evaluating the production of IgG subtypes, as expected, we found that formulations containing Poly(I:C) induced IgG2a whereas Alum did not. The combination of these two adjuvants induced high levels of both IgG1 and IgG2a. In addition, cellular immune responses of CD4+ and CD8+ T cells producing interferon-gamma were equivalent, demonstrating that the Alum + Poly(I:C) combination supported a Th1 profile. Based on the high neutralizing titers, we evaluated B cells in the germinal centers, which are specific for receptor-binding domain (RBD) and spike, and observed that more positive B cells were induced upon the Alum + Poly(I:C) combination. Moreover, these B cells produced antibodies against both RBD and non-RBD sites. We also studied the impact of this vaccination preparation (S Ptn with Alum + Poly(I:C)) in the lungs of mice challenged with inactivated SARS-CoV-2 virus. We found a production of IgG, but not IgA, and a reduction in neutrophil recruitment in the bronchoalveolar lavage fluid (BALF) of mice, suggesting that our immunization scheme reduced lung inflammation. Altogether, our data suggest that Alum and Poly(I:C) together is a possible adjuvant combination for vaccines against SARS-CoV-2 by the intradermal route.

scholarly journals Paratuberculosis.

1994 ◽  
Vol 7 (3) ◽  
pp. 328-345 ◽  
Author(s):  
C Cocito ◽  
P Gilot ◽  
M Coene ◽  
M de Kesel ◽  
P Poupart ◽  
...  
Keyword(s):  
Cell Wall ◽  
Pcr Amplification ◽  
Johne's Disease ◽  
Johne’S Disease ◽  
Enzyme Linked Immunosorbent Assay ◽  
Polymorphism Analysis ◽  
Mycobacterial Antigen ◽  
Immune Reactions ◽  
Species Specific ◽  
Cellular Immune

Paratuberculosis (Johne's disease) is a chronic, wasting, widespread mycobacteriosis of ruminants. It involves extensive mycobacterial shedding, which accounts for the high contagiousness, and ends with a fatal enteritis. Decreases in weight, milk production, and fertility produce severe economic loss. The DNA of the etiological agent (Mycobacterium paratuberculosis) has a base composition (66 to 67% G+C) within the range of that of mycobacteria (62 to 70% G+C), a size (4.4 x 10(6) to 4.7 x 10(6) bp) larger than that of most pathogenic mycobacteria (2.0 x 10(6) to 4.2 x 10(6) bp), and a high relatedness (> 90%) to Mycobacterium avium DNA. However, the DNAs of the two organisms can be distinguished by restriction fragment length polymorphism analysis. M. paratuberculosis genes coding for a transposase, a cell wall-associated protein (P34), and two heat shock proteins have been cloned and sequenced. Nucleic acid probes (two of which are species specific) are used, after PCR amplification, for M. paratuberculosis identification in stools and milk. As in leprosy, with disease progression, cellular immune reactions decrease and humoral immune reactions increase. Cutaneous testing with sensitins, lymphocyte proliferation assays, and cytokine tests are used to monitor cellular immune reactions in paratuberculosis, but these tests lack specificity. Complement fixation, immunodiffusion, and enzymometric tests based on antibodies to M. paratuberculosis extracts, to mycobacterial antigen complex A36, to glycolipids, and to proteins help identify affected cattle but are not species specific. The carboxyl-terminal portion of the 34-kDa cell wall-associated A36 protein (P34) carries species-specific B-cell epitopes and is the basis for an enzyme-linked immunosorbent assay. Diagnostic tests for paratuberculosis are also used in Crohn's disease, a chronic human ileitis mimicking Johne's disease, in which isolates identified as M. paratuberculosis have been found.

scholarly journals Feline Immunodeficiency Virus Vif Localizes to the Nucleus

2000 ◽  
Vol 74 (6) ◽  
pp. 2533-2540 ◽  
Author(s):  
Udayan Chatterji ◽  
Chris K. Grant ◽  
John H. Elder
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Primary Role ◽  
Cytoplasmic Localization ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Hiv Type 1 ◽  
Species Specific

ABSTRACT Monoclonal antibodies prepared against recombinant Vif derived from the 34TF10 strain of feline immunodeficiency virus (FIV) were used to assess the expression and localization of Vif in virus-infected cells. Analyses by Western blotting and by immunoprecipitation from cells infected with FIV-34TF10 revealed the presence of a single 29-kDa species specific for virus-infected cells. Confirmation of antibody specificity was also performed by specific immunoprecipitation of in vitro-transcribed and -translated recombinant Vif. Localization experiments were also performed on virus-infected cells, using different fixation procedures. Results for methanol fixation protocols similar to those reported for localization of human immunodeficiency virus (HIV) Vif showed a predominant cytoplasmic localization for FIV Vif, very similar to localization of HIV type 1 Vif and virtually identical to the localization observed for the Gag antigens of the virus. However, with milder fixation procedures that used 2% formaldehyde at 4°C, FIV Vif was strongly evident in the nucleus. The localization was distinct from the nuclear localization noted with Rev and did not involve the nucleolus. Attempts to show colocalization or coprecipitation of Vif with Gag antigens were unsuccessful. In addition, Vif was not detected in purified FIV virions. The results are consistent with the notion that the primary role of Vif in virus infection initiates in the nucleus.

Novel Toxin-antitoxin System Xn-mazEF from Xenorhabdus nematophi-la: Identification, Characterization and Functional Exploration

2020 ◽  
Vol 16 ◽  
Author(s):  
Jogendra Singh Nim ◽  
Mohit Yadav ◽  
Lalit Kumar Gautam ◽  
Chaitali Ghosh ◽  
Shakti Sahi ◽  
...  
Keyword(s):  
Interaction Analysis ◽  
Functional Characterization ◽  
Host Cells ◽  
System Control ◽  
Xenorhabdus Nematophila ◽  
Functional Features ◽  
Dynamics Simulations ◽  
Species Specific ◽  
Rna Interaction

Background: Xenorhabdus nematophila maintains species-specific mutual interaction with nematodes of Steinernema genus. Type II Toxin Antitoxin (TA) systems, the mazEF TA system controls stress and programmed cell death in bacteria. Objective: This study elucidates the functional characterization of Xn-mazEF, a mazEF homolog in X. nematophila by computational and in vitro approaches. Methods: 3 D- structural models for Xn-MazE toxin and Xn-MazF antitoxin were generated, validated and characterized for protein - RNA interaction analysis. Further biological and cellular functions of Xn-MazF toxin were also predicted. Molecular dynamics simulations of 50ns for Xn-MazF toxin complexed with nucleic acid units (DU, RU, RC, and RU) were performed. The MazF toxin and complete MazEF operon were endogenously expressed and monitored for the killing of Escherichia coli host cells under arabinose induced tightly regulated system. Results: Upon induction, E. coli expressing toxin showed rapid killing within four hours and attained up to 65% growth inhibition, while the expression of the entire operon did not show significant killing. The observation suggests that the Xn-mazEF TA system control transcriptional regulation in X. nematophila and helps to manage stress or cause toxicity leading to programmed death of cells. Conclusion: The study provides insights into structural and functional features of novel toxin, XnMazF and provides an initial inference on control of X. nematophila growth regulated by TA systems.

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