scholarly journals Identification of the Binding Site of Apical Membrane Antigen 1 (AMA1) Inhibitors Using a Paramagnetic Probe

ChemMedChem ◽  
2019 ◽  
Vol 14 (5) ◽  
pp. 603-612
Author(s):  
Mansura Akter ◽  
Nyssa Drinkwater ◽  
Shane M. Devine ◽  
Simon C. Drew ◽  
Bankala Krishnarjuna ◽  
...  
Keyword(s):  
Binding Site ◽  
Apical Membrane ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Paramagnetic Probe

scholarly journals Expression, Purification, and Biological Characterization of Babesia microti Apical Membrane Antigen 1

2015 ◽  
Vol 83 (10) ◽  
pp. 3890-3901 ◽  
Author(s):  
Prasun Moitra ◽  
Hong Zheng ◽  
Vivek Anantharaman ◽  
Rajdeep Banerjee ◽  
Kazuyo Takeda ◽  
...  
Keyword(s):  
Apical Membrane ◽  
The United States ◽  
Host Cells ◽  
Health Concern ◽  
Babesia Microti ◽  
Type I ◽  
Content Type ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Extracellular Region

The intraerythrocytic apicomplexanBabesia microti, the primary causative agent of human babesiosis, is a major public health concern in the United States and elsewhere. Apicomplexans utilize a multiprotein complex that includes a type I membrane protein called apical membrane antigen 1 (AMA1) to invade host cells. We have isolated the full-lengthB. microtiAMA1 (BmAMA1) gene and determined its nucleotide sequence, as well as the amino acid sequence of the AMA1 protein. This protein contains an N-terminal signal sequence, an extracellular region, a transmembrane region, and a short conserved cytoplasmic tail. It shows the same domain organization as the AMA1 orthologs from piroplasm, coccidian, and haemosporidian apicomplexans but differs from all other currently known piroplasmida, including otherBabesiaandTheileriaspecies, in lacking two conserved cysteines in highly variable domain III of the extracellular region. Minimal polymorphism was detected in BmAMA1 gene sequences of parasite isolates from six babesiosis patients from Nantucket. Immunofluorescence microscopy studies showed that BmAMA1 is localized on the cell surface and cytoplasm near the apical end of the parasite. Native BmAMA1 from parasite lysate and refolded recombinant BmAMA1 (rBmAMA1) expressed inEscherichia colireacted with a mouse anti-BmAMA1 antibody using Western blotting.In vitrobinding studies showed that both native BmAMA1 and rBmAMA1 bind to human red blood cells (RBCs). This binding is trypsin and chymotrypsin treatment sensitive but neuraminidase independent. Incubation ofB. microtiparasites in human RBCs with a mouse anti-BmAMA1 antibody inhibited parasite growth by 80% in a 24-h assay. Based on its antigenically conserved nature and potential role in RBC invasion, BmAMA1 should be evaluated as a vaccine candidate.

scholarly journals CD4+T Cells Acting Independently of Antibody Contribute to Protective Immunity toPlasmodiumchabaudiInfection After Apical Membrane Antigen 1 Immunization

2000 ◽  
Vol 165 (1) ◽  
pp. 389-396 ◽  
Author(s):  
Huji Xu ◽  
Anthony N. Hodder ◽  
Huara Yan ◽  
Pauline E. Crewther ◽  
Robin F. Anders ◽  
...  
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Protective Immunity ◽  
Apical Membrane ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals The Most Polymorphic Residue on Plasmodium falciparum Apical Membrane Antigen 1 Determines Binding of an Invasion-Inhibitory Antibody

2006 ◽  
Vol 74 (5) ◽  
pp. 2628-2636 ◽  
Author(s):  
A. M. Coley ◽  
K. Parisi ◽  
R. Masciantonio ◽  
J. Hoeck ◽  
J. L. Casey ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Apical Membrane ◽  
Site Directed Mutagenesis ◽  
Supporting Evidence ◽  
Inhibitory Antibody ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Immune Pressure ◽  
Polymorphic Residue

ABSTRACT Apical membrane antigen 1 (AMA1) is currently one of the leading malarial vaccine candidates. Anti-AMA1 antibodies can inhibit the invasion of erythrocytes by Plasmodium merozoites and prevent the multiplication of blood-stage parasites. Here we describe an anti-AMA1 monoclonal antibody (MAb 1F9) that inhibits the invasion of Plasmodium falciparum parasites in vitro. We show that both reactivity of MAb 1F9 with AMA1 and MAb 1F9-mediated invasion inhibition were strain specific. Site-directed mutagenesis of a fragment of AMA1 displayed on M13 bacteriophage identified a single polymorphic residue in domain I of AMA1 that is critical for MAb 1F9 binding. The identities of all other polymorphic residues investigated in this domain had little effect on the binding of the antibody. Examination of the P. falciparum AMA1 crystal structure localized this residue to a surface-exposed α-helix at the apex of the polypeptide. This description of a polymorphic inhibitory epitope on AMA1 adds supporting evidence to the hypothesis that immune pressure is responsible for the polymorphisms seen in this molecule.

Analysis of the Plasmodium vivax apical membrane antigen-1 gene from re-emerging Korean isolates

2003 ◽  
Vol 90 (4) ◽  
pp. 325-329 ◽  
Author(s):  
Joon-Yong Chung ◽  
Eui-Hyun Chun ◽  
Jin-Ho Chun ◽  
Weon-Gyu Kho
Keyword(s):  
Plasmodium Vivax ◽  
Apical Membrane ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals High-Level Expression of Plasmodium vivax Apical Membrane Antigen 1 (AMA-1) in Pichia pastoris: Strong Immunogenicity in Macaca mulatta Immunized with P. vivax AMA-1 and Adjuvant SBAS2

1999 ◽  
Vol 67 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Clemens H. M. Kocken ◽  
Martin A. Dubbeld ◽  
Annemarie Van Der Wel ◽  
Jack T. Pronk ◽  
Andrew P. Waters ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Plasmodium Vivax ◽  
Apical Membrane ◽  
Gel Filtration ◽  
Methylotrophic Yeast ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
High Level

ABSTRACT The apical membrane antigen 1 (AMA-1) family is a promising family of malaria blood-stage vaccine candidates that have induced protection in rodent and nonhuman primate models of malaria. Correct conformation of the protein appears to be essential for the induction of parasite-inhibitory responses, and these responses appear to be primarily antibody mediated. Here we describe for the first time high-level secreted expression (over 50 mg/liter) of thePlasmodium vivax AMA-1 (PV66/AMA-1) ectodomain by using the methylotrophic yeast Pichia pastoris. To prevent nonnative glycosylation, a conservatively mutagenized PV66/AMA-1 gene (PV66Δglyc) lacking N-glycosylation sites was also developed. Expression of the PV66Δglyc ectodomain yielded similar levels of a homogeneous product that was nonglycosylated and was readily purified by ion-exchange and gel filtration chromatographies. Recombinant PV66Δglyc43–487 was reactive with conformation-dependent monoclonal antibodies. With the SBAS2 adjuvant,Pichia-expressed PV66Δglyc43–487 was highly immunogenic in five rhesus monkeys, inducing immunoglobulin G enzyme-linked immunosorbent assay titers in excess of 1:200,000. This group of monkeys had a weak trend showing lower cumulative parasite loads following a Plasmodium cynomolgi infection than in the control group.

scholarly journals Further investigation of the characteristics and biological function of Eimeria tenella apical membrane antigen 1

Parasite ◽  
2020 ◽  
Vol 27 ◽  
pp. 70
Author(s):  
Qingjie Wang ◽  
Qiping Zhao ◽  
Shunhai Zhu ◽  
Bing Huang ◽  
Shuilan Yu ◽  
...  
Keyword(s):  
Rna Binding ◽  
Apical Membrane ◽  
Mapk Signaling ◽  
Eimeria Tenella ◽  
Host Cells ◽  
Differentially Expressed ◽  
Type I ◽  
Dependent Manner ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

Apical membrane antigen 1 (AMA1) is a type I integral membrane protein that is highly conserved in apicomplexan parasites. Previous studies have shown that Eimeria tenella AMA1 (EtAMA1) is critical for sporozoite invasion of host cells. Here, we show that EtAMA1 is a microneme protein secreted by sporozoites, confirming previous results. Individual and combined treatment with antibodies of EtAMA1 and its interacting proteins, E. tenella rhoptry neck protein 2 (EtRON2) and Eimeria-specific protein (EtESP), elicited significant anti-invasion effects on the parasite in a concentration-dependent manner. The overexpression of EtAMA1 in DF-1 cells showed a significant increase of sporozoite invasion. Isobaric tags for relative and absolute quantitation (iTRAQ) coupled with LC-MS/MS were used to screen differentially expressed proteins (DEPs) in DF-1 cells transiently transfected with EtAMA1. In total, 3953 distinct nonredundant proteins were identified and 163 of these were found to be differentially expressed, including 91 upregulated proteins and 72 downregulated proteins. The DEPs were mainly localized within the cytoplasm and were involved in protein binding and poly(A)-RNA binding. KEEG analyses suggested that the key pathways that the DEPs belonged to included melanogenesis, spliceosomes, tight junctions, and the FoxO and MAPK signaling pathways. The data in this study not only provide a comprehensive dataset for the overall protein changes caused by EtAMA1 expression, but also shed light on EtAMA1’s potential molecular mechanisms during Eimeria infections.

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