Acanthamoeba spp. monoclonal antibody against a CPA2 transporter: a promising molecular tool for acanthamoebiasis diagnosis and encystment study

Parasitology ◽  
2020 ◽  
Vol 147 (14) ◽  
pp. 1678-1688
Author(s):  
Michele Martha Weber-Lima ◽  
Bianca Prado-Costa ◽  
Alessandra Becker-Finco ◽  
Adriana Oliveira Costa ◽  
Philippe Billilad ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Diagnostic Methods ◽  
Free Living ◽  
Immunoprecipitation Assay ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Amoebic Keratitis ◽  
Low Sensitivity

AbstractFree-living amoeba of the genus Acanthamoeba are ubiquitous protozoa involved in opportunistic and non-opportunistic infection in humans, such as granulomatous amoebic encephalitis and amoebic keratitis. Both infections have challenging characteristics such as the formation of the resistant cysts in infected tissues, hampering the treatment and most usual diagnosis depending on time-consuming and/or low sensitivity techniques. The use of monoclonal antibodies presents itself as an opportunity for the development of more effective alternative diagnostic methods, as well as an important and useful tool in the search for new therapeutic targets. This study investigated the possibility of using a previously produced monoclonal antibody (mAb3), as a diagnostic tool for the detection of Acanthamoeba trophozoites by direct and indirect flow cytometry and immunofluorescence. Immunoprecipitation assay and mass spectrometry allowed the isolation of the antibody's target and suggested it is a transporter part of the CPA (cation: proton antiporter) superfamily. In vitro tests indicate an important role of this target in Acanthamoeba's encystment physiology. Our results support the importance of studying the role of CPA2 transporters in the context of acanthamoebiasis, as this may be a way to identify new therapeutic candidates.

scholarly journals Encystment Induces Down-Regulation of an Acetyltransferase-Like Gene in Acanthamoeba castellanii

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 321 ◽  
Author(s):  
Steven Rolland ◽  
Luce Mengue ◽  
Cyril Noël ◽  
Stéphanie Crapart ◽  
Anne Mercier ◽  
...  
Keyword(s):  
Bioinformatics Analysis ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Adverse Conditions ◽  
Genetic Modifications ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Causative Agents

Acanthamoeba castellanii is a ubiquitous free-living amoeba. Pathogenic strains are causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. In response to adverse conditions, A. castellanii differentiate into cysts, which are metabolically inactive and resistant cells. This process, also named encystment, involves biochemical and genetic modifications that remain largely unknown. This study characterizes the role of the ACA1_384820 Acanthamoeba gene during encystment. This gene encodes a putative N-acetyltransferase, belonging to the Gcn5-related N-acetyltransferase (GNAT) family. We showed that expression of the ACA1_384820 gene was down-regulated as early as two hours after induction of encystment in A. castellanii. Interestingly, overexpression of the ACA1_384820 gene affects formation of cysts. Unexpectedly, the search of homologs of ACA1_384820 in the Eukaryota gene datasets failed, except for some species in the Acanthamoeba genus. Bioinformatics analysis suggested a possible lateral acquisition of this gene from prokaryotic cells. This study enabled us to describe a new Acanthamoeba gene that is down-regulated during encystment.

Comparative analyses of different genetic markers for the detection of Acanthamoeba spp. isolates

2014 ◽  
Vol 59 (3) ◽  
Author(s):  
Monika Derda ◽  
Agnieszka Wojtkowiak-Giera ◽  
Edward Hadaś
Keyword(s):  
Genetic Markers ◽  
Tap Water ◽  
Correct Diagnosis ◽  
Specific Marker ◽  
Pcr Assay ◽  
Free Living ◽  
Detection And Identification ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Treatment Of Infection

AbstractAcanthamoeba are widespread free-living amoebae which may cause granulomatous amoebic encephalitis (GAE), keratitis, skin ulcerations and disseminated tissue infection. An important diagnostic and prognostic factor for the treatment of infection is a quick and correct diagnosis of amoebae strains. The aim of our study was to develop a rapid method for detection and identification of pathogenic Acanthamoeba spp. strains from diagnostic material collected from water. In this study we analysed five amplification-based genetic markers (Aca 16S, Ac6/210, GP, JDP, Nelson) used for identification of pathogenic Acanthamoeba spp. strains isolated in water sources in Poland, Iceland and Sweden. Our results demonstrated the presence of pathogenic Acanthamoeba strains in tap water. PCR assay appeared to be a more rapid and sensitive method to detect the presence of amoebae than the limited conventional techniques. Based on our observations, we can confirm that the use of four out of five genetic markers (Aca 16S, Ac 6/210, JDP, GP, Nelson) may be helpful in identification of Acanthamoeba spp. strains, but only one Aca 16S primer pair is a highly specific marker that distinguishes between pathogenic strains of Acanthamoeba and other free-living amoeba families.

scholarly journals Immunity to pathogenic free-living amoebae: role of cell-mediated immunity

1980 ◽  
Vol 29 (2) ◽  
pp. 408-410
Author(s):  
R T Cursons ◽  
T J Brown ◽  
E A Keys ◽  
K M Moriarty ◽  
D Till
Keyword(s):  
Immune System ◽  
Inhibition Test ◽  
Delayed Hypersensitivity ◽  
Cell Mediated Immunity ◽  
Pathogenic Species ◽  
Free Living

The role of cell-mediated immunity in defense against pathogenic free-living amoebae was examined. Both the in vitro macrophage inhibition test and the in vivo delayed hypersensitivity test showed responses to both heterologous and homologous antigens, although homologous systems were the most efficient. It is suggested that exposure to nonpathogenic species of free-living amoebae can stimulate the immune system to be effective against pathogenic species. The significance of cell-mediated immunity as a defense against invasion by pathogenic free-living amoebae is discussed.

scholarly journals A critical role of VLA-4 in erythropoiesis in vivo

Blood ◽  
1996 ◽  
Vol 87 (6) ◽  
pp. 2513-2517 ◽  
Author(s):  
K Hamamura ◽  
H Matsuda ◽  
Y Takeuchi ◽  
S Habu ◽  
H Yagita ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Fetal Liver ◽  
Critical Role ◽  
In Utero ◽  
In Vitro Studies ◽  
Specific Interactions ◽  
Erythroid Progenitors

Hematopoiesis requires specific interactions with the microenvironments, and VLA-4 has been implicated in these interactions based on in vitro studies. To study the role of VLA-4 in hematopoiesis in vivo, we performed in utero treatment of mice with an anti-VLA-4 monoclonal antibody. Although all hematopoietic cells in fetal liver expressed VLA-4, the treatment specifically induced anemia. It had no effect on the development of nonerythroid lineage cells, including lymphoids and myeloids. In the treated liver almost no erythroblast was detected, whereas the erythroid progenitors, which give rise to erythroid colonies in vitro, were present. These results indicate that VLA-4 plays a critical role in erythropoiesis, while it is not critical in lymphopoiesis in vivo.

scholarly journals Isoniazid Conjugated Magnetic Nanoparticles Loaded with Amphotericin B as a Potent Antiamoebic Agent against Acanthamoeba castellanii

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 276
Author(s):  
Kawish Iqbal ◽  
Sumayah Abdelnasir Osman Abdalla ◽  
Ayaz Anwar ◽  
Kanwal Muhammad Iqbal ◽  
Muhammad Raza Shah ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Amphotericin B ◽  
Central Nervous System Infection ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Granulomatous Amoebic Encephalitis ◽  
Nano Drug Delivery ◽  
Free Living Amoeba ◽  
Acanthamoeba Species

The pathogenic free-living amoeba, Acanthamoeba castellanii, is responsible for a rare but deadly central nervous system infection, granulomatous amoebic encephalitis and a blinding eye disease called Acanthamoeba keratitis. Currently, a combination of biguanides, amidine, azoles and antibiotics are used to manage these infections; however, the host cell cytotoxicity of these drugs remains a challenge. Furthermore, Acanthamoeba species are capable of transforming to the cyst form to resist chemotherapy. Herein, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with isoniazid, which were further loaded with amphotericin B (ISO-NPs-AMP) to cause potent antiamoebic effects against Acanthamoeba castellanii. The IC50 of isoniazid conjugated with magnetic nanoparticles and loaded with amphotericin B was found to be 45 μg/mL against Acanthamoeba castellanii trophozoites and 50 μg/mL against cysts. The results obtained in this study have promising implications in drug discovery as these nanomaterials exhibited high trophicidal and cysticidal effects, as well as limited cytotoxicity against rat and human cells.

scholarly journals Role of interleukin-1 and tumour necrosis factor in leukocyte recruitment to acute dermal inflammation

1992 ◽  
Vol 1 (5) ◽  
pp. 347-353 ◽  
Author(s):  
Andrew C. Issekutz ◽  
Nancy Lopes ◽  
Thomas B. Issekutz
Keyword(s):  
Monoclonal Antibody ◽  
Umbilical Vein ◽  
Interleukin 1 ◽  
E Coli ◽  
Tnf Α ◽  
Lps Activation ◽  
Necrosis Factor

The cytokines IL-1 and TNF-α are involved in inflammation and their production is stimulated by various agents, especially endotoxin (LPS). Here, using the human IL-1 receptor antagonist (IL-1RA) and a new monoclonal antibody (mAb 7F11) to rabbit TNF, the role of endogenous IL-l and TNF production in acute (3h) leukocyte (PMNL) recruitment to dermal inflammation in rabbits has been studied. IL-1RA inhibited by 27% the PMNL accumulation in reactions induced by killed Escherichia coli (p < 0.05) but not by LPS. The monoclonal antibody to TNF inhibited by 27% and 38% (p < 0.002) the PMNL accumulation in LPS and E. coli reactions respectively, but a combination of the mAb with IL-1RA was not more effective. Treatment of human umbilical vein endothelium with LPS for 3 h activated endothelium to induce PMNL transendothelial migration in vitro, which was not inhibited by IL-1RA, antibody to TNF-α, IL-1 or to IL-8. In conclusion, TNF and IL-1 may partially mediate acute PMNL infiltration in vivo to LPS and Gram negative bacteria, but there is a major IL-1/TNF independent mechanism, at least in dermal inflammation, which may be due to direct LPS activation of the microvasculature or perhaps the generation of cytokines other than IL-1 and TNF.

scholarly journals Inhibition of murine B and T lymphopoiesis in vivo by an anti-interleukin 7 monoclonal antibody.

1993 ◽  
Vol 178 (1) ◽  
pp. 257-264 ◽  
Author(s):  
K H Grabstein ◽  
T J Waldschmidt ◽  
F D Finkelman ◽  
B W Hess ◽  
A R Alpert ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
B Cells ◽  
B Cell ◽  
Culture Methods ◽  
Cell Stage ◽  
Interleukin 7 ◽  
Slow Turnover

The effects of interleukin 7 (IL-7) on the growth and differentiation of murine B cell progenitors has been well characterized using in vitro culture methods. We have investigated the role of IL-7 in vivo using a monoclonal antibody that neutralizes IL-7. We find that treatment of mice with this antibody completely inhibits the development of B cell progenitors from the pro-B cell stage forward. We also provide evidence that all peripheral B cells, including those of the B-1 and conventional lineages, are derived from IL-7-dependent precursors. The results are consistent with the rapid turnover of B cell progenitors in the marrow, but a slow turnover of mature B cells in the periphery. In addition to effects on B cell development, anti-IL-7 treatment substantially reduced thymus cellularity, affecting all major thymic subpopulations.

scholarly journals Proteolytic processing of a protein involved in sperm-egg fusion correlates with acquisition of fertilization competence.

1990 ◽  
Vol 111 (1) ◽  
pp. 69-78 ◽  
Author(s):  
C P Blobel ◽  
D G Myles ◽  
P Primakoff ◽  
J M White
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Developmental Stages ◽  
Biochemical Properties ◽  
Proteolytic Processing ◽  
Molecular Forms ◽  
Membrane Glycoprotein ◽  
Processing Step

A protein located on the surface of guinea pig sperm (PH-30) has been implicated in the process of sperm-egg fusion (Primakoff, P., H. Hyatt, and J. Tredick-Kline. 1987. J. Cell Biol. 104:141-149). In this paper we have assessed basic biochemical properties of PH-30 and have analyzed the molecular forms of PH-30 present at different stages of sperm maturation. We show the following: (a) PH-30 is an integral membrane glycoprotein; (b) it is composed of two tightly associated and immunologically distinct subunits; (c) both subunits are made as larger precursors; (d) processing of the two subunits occurs at different developmental stages; (e) the final processing step occurs in the region of the epididymis where sperm become fertilization competent; (f) processing can be mimicked in vitro; (g) processing exposes at least two new epitopes on PH-30-one of the newly exposed epitopes is recognized by a fusion-inhibitory monoclonal antibody. These results are discussed in terms of the possible role of PH-30 in mediating fusion with the egg plasma membrane.

DEMONSTRATION OF Cl-INHIBITOR COMPLEXES IN PLASMA BY HIGHLY SENSITIVE RADIOIMMUNOASSAYS USING A MONOCLONAL ANTIBODY AGAINST A NEODETERMINANT ON COMPLEXED Cl-INHIBITOR

1987 ◽  
Author(s):  
J H Nuijens ◽  
C C M Huijbregets ◽  
L G Thijs ◽  
C E Hack
Keyword(s):  
Monoclonal Antibody ◽  
Contact System ◽  
Factor Xii ◽  
Optimal Conditions ◽  
Spleen Cells ◽  
Highly Sensitive ◽  
Factor Xiia

Levels of factor XIIa- and kallikrein-Cl inhibitor (Cl-Inh) complexes in plasma reflect activation of the contact system in vivo. Here, we report the development of radioimmunoassays (RIAs) for these complexes using a monoclonal antibody (mAb K0K12) that reacts with a neodeterminant exposed on Cl-Inh after interaction with proteases. mAb K0K12 was obtained by a fusion experiment with spleen cells of a mouse hyperimmunized with Cl-Inh complexes.Experiments with purified Cl-Inh incubated with either Cls or elastase revealed that the determinant for mAb KOK12 is exposed on complexed as well as proteolytically inactivated (modified) Cl-Inh.Radioimmunoassays (RIAs) for the detection of factor Xlla-Cl-Inh and kallikrein-Cl-Inh complexes were performed as follows: mAb K0K12 was coupled to Sepharose and incubated with the sample to be tested. Binding of Cl-Inh complexes was detected by a subsequent incubation with 125I-antibodies against factor XII or (pre)kallikrein.With these RIAs, activation of 0.1% of factor XII or prekal-likrein in plasma is easily detected.Optimal conditions for blood sampling and processing were established, i.e. conditions that prevented any in vitro activation of factor XII and prekallikrein. Levels of factor XIIa-Cl-Inh and kallikrein-Cl-Inh complexes in plasma samples from normal donors were less than 0.1 U/ml (100 U/ml is the maximal amount of Cl-Inh complexes generated in pooled plasma by DXS). Considerably higher, and fluctuating levels were observed in patients with diseases such as septicaemia. These highly sensitive RIAs will facilitate studies concerning the role of the contact system in human pathophysiology.

PMN adherence to cat ischemic-reperfused mesenteric vascular endothelium under flow: role of P-selectin

1994 ◽  
Vol 76 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. M. Lefer ◽  
X. L. Ma
Keyword(s):  
Monoclonal Antibody ◽  
Vascular Endothelium ◽  
Polymorphonuclear Leukocyte ◽  
Mesenteric Artery ◽  
Ischemia And Reperfusion ◽  
Shear Rates ◽  
Arterial Endothelium

We studied polymorphonuclear leukocyte (PMN) adherence to cat ischemic-reperfused mesenteric artery and vein endothelia under conditions of flow in vitro. Under physiological shear rates, only a few PMNs adhered to non-ischemic-reperfused arterial and venous endothelia (11 +/- 2 and 20 +/- 3 PMN/mm2, respectively). However, after 60 min of ischemia and 20 or 120 min of reperfusion, a significant increase in PMN adherence to arterial endothelium was observed. At 20 min of reperfusion, 44 +/- 4 PMN/mm2 adhered, and at 120 min postreperfusion, 63 +/- 12 PMN/mm2 adhered (P < 0.01 from control). Moreover, a greater degree of PMN adherence occurred on the venous than on the arterial endothelium. Thus, 159 +/- 10 and 198 +/- 12 PMN/mm2 adhered to mesenteric venous endothelium isolated after 20 and 120 min reperfusion, respectively (P < 0.01 vs. arteries). Furthermore, addition of PB 1.3 (20 micrograms/ml), a monoclonal antibody against P-selectin, 5 min before perfusion with PMNs significantly attenuated the increase in PMN adherence to both arterial and venous endothelia (P < 0.01). These results indicate that PMN-endothelial interaction also occurs in conduit vessels after ischemia and reperfusion, although a more profound PMN adherence occurs in veins.

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