scholarly journals Purification of native histidine-rich protein 2 (nHRP2) from Plasmodium falciparum culture supernatant, infected RBCs, and parasite lysate

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Balwan Singh ◽  
Jessica N. McCaffery ◽  
Amy Kong ◽  
Yong Ah ◽  
Scott Wilson ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Plasmodium Falciparum ◽  
Culture Supernatant ◽  
Biochemical Characterization ◽  
Metal Chelate ◽  
Total Yield ◽  
Nickel Metal ◽  
Sds Page ◽  
Infected Rbcs ◽  
Parasite Lysate

Abstract Background Despite the widespread use of histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs), purified native HRP2 antigen is not standardly used in research applications or assessment of RDTs used in the field. Methods This report describes the purification of native HRP2 (nHRP2) from the HB3 Plasmodium falciparum culture strain. As this culture strain lacks pfhrp3 from its genome, it is an excellent source of HRP2 protein only and does not produce the closely-related HRP3. The nHRP2 protein was isolated from culture supernatant, infected red blood cells (iRBCs), and whole parasite lysate using nickel-metal chelate chromatography. Biochemical characterization of nHRP2 from HB3 culture was conducted by SDS-PAGE and western blotting, and nHRP2 was assayed by RDT, ELISA, and bead-based immunoassay. Results Purified nHRP2 was identified by SDS-PAGE and western blot as a − 60 kDa protein that bound anti-HRP-2 monoclonal antibodies. Mouse anti-HRP2 monoclonal antibody was found to produce high optical density readings between dilutions of 1:100 and 1:3,200 by ELISA with assay signal observed up to a 1:200,000 dilution. nHRP2 yield from HB3 culture by bead-based immunoassay revealed that both culture supernatant and iRBC lysate were practical sources of large quantities of this antigen, producing a total yield of 292.4 µg of nHRP2 from two pooled culture preparations. Assessment of nHRP2 recognition by RDTs revealed that Carestart Pf HRP2 and HRP2/pLDH RDTs detected purified nHRP2 when applied at concentrations between 20.6 and 2060 ng/mL, performing within a log-fold dilution of commercially-available recombinant HRP2. The band intensity observed for the nHRP2 dilutions was equivalent to that observed for P. falciparum culture strain dilutions of 3D7 and US06 F Nigeria XII between 12.5 and 1000 parasites/µL. Conclusions Purified nHRP2 could be a valuable reagent for laboratory applications as well as assessment of new and existing RDTs prior to their use in clinical settings. These results establish that it is possible to extract microgram quantities of the native HRP2 antigen from HB3 culture and that this purified protein is well recognized by existing monoclonal antibody lines and RDTs. Graphical Abstract

scholarly journals Purification of Native Histidine-Rich Protein 2 (Nhrp2) from Plasmodium Falciparum Culture Supernatant, Infected Rbcs, and Parasite Lysate

2021 ◽  
Author(s):  
Balwan Singh ◽  
Jessica N McCaffery ◽  
Amy Kong ◽  
Yong Ah ◽  
Scott Wilson ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Culture Supernatant ◽  
Biochemical Characterization ◽  
Metal Chelate ◽  
Total Yield ◽  
Clinical Settings ◽  
Nickel Metal ◽  
Sds Page ◽  
Infected Rbcs ◽  
Parasite Lysate

Abstract Background: Despite the widespread use of histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs), purified native HRP2 antigen is not standardly used in research applications or assessment of RDTs used in the field.Methods: This report describes purification of native HRP2 (nHRP2) from the HB3 P. falciparum culture strain. As this culture strain lacks pfhrp3 from its genome, it is an excellent source of HRP2 protein only, and does not produce the closely-related HRP3. The nHRP2 protein was isolated from culture supernatant, infected red blood cells (iRBCs), and whole parasite lysate using nickel-metal chelate chromatography. Biochemical characterization of nHRP2 from HB3 culture was conducted by SDS-PAGE and western blotting, and nHRP2 was assayed by RDT, ELISA, and bead-based immunoassay.Results: Purified nHRP2 was identified by SDS-PAGE and western blot as a ~60 kDa protein that bound anti-HRP-2 monoclonal antibodies. Mouse anti-HRP2 monoclonal antibody was found to produce high optical density readings between dilutions of 1:100 and 1:3,200 by ELISA with assay signal observed up to a 1:200,000 dilution. nHRP2 yield from HB3 culture by bead-based immunoassay revealed that both culture supernatant and iRBC lysate were practical sources of large quantities of this antigen, producing a total yield of 292.4 µg of nHRP2 from two pooled culture preparations. Assessment of nHRP2 recognition by RDTs revealed that Carestart Pf HRP2 and HRP2/pLDH RDTs detected purified nHRP2 when applied at concentrations between 20.6 to 2060 ng/mL, performing within a log-fold dilution of commercially-available recombinant HRP2. The band intensity observed for the nHRP2 dilutions was equivalent to that observed for P. falciparum culture strain dilutions of 3D7 and US06 F Nigeria XII between 12.5 and 1,000 parasites/µl.Conclusions: Purified nHRP2 could be a valuable reagent for laboratory applications as well as assessment of new and existing RDTs prior to their use in clinical settings. These results establish that it is possible to extract microgram quantities of the native HRP2 antigen from HB3 culture and that this purified protein is well recognized by existing monoclonal antibody lines and RDTs.

scholarly journals Purification of Native Histidine-Rich Protein 2 (nHRP2) from Plasmodium Falciparum Culture Supernatant, Infected Rbcs, and Parasite Lysate

2021 ◽  
Author(s):  
Balwan Singh ◽  
Jessica N. McCaffery ◽  
Amy Kong ◽  
Yong Ah ◽  
Scott A. Wilson ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Culture Supernatant ◽  
Biochemical Characterization ◽  
Metal Chelate ◽  
Total Yield ◽  
Clinical Settings ◽  
Nickel Metal ◽  
Sds Page ◽  
Infected Rbcs ◽  
Parasite Lysate

Abstract Background: Despite the widespread use of histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs), purified native HRP2 antigen is not standardly used in research applications or assessment of RDTs used in the field.Methods: This report describes the purification of native HRP2 (nHRP2) from the HB3 P. falciparum culture strain. As this culture strain lacks pfhrp3 from its genome, it is an excellent source of HRP2 protein only and does not produce the closely-related HRP3. The nHRP2 protein was isolated from culture supernatant, infected red blood cells (iRBCs), and whole parasite lysate using nickel-metal chelate chromatography. Biochemical characterization of nHRP2 from HB3 culture was conducted by SDS-PAGE and western blotting, and nHRP2 was assayed by RDT, ELISA, and bead-based immunoassay.Results: Purified nHRP2 was identified by SDS-PAGE and western blot as a ~60 kDa protein that bound anti-HRP-2 monoclonal antibodies. Mouse anti-HRP2 monoclonal antibody was found to produce high optical density readings between dilutions of 1:100 and 1:3,200 by ELISA with assay signal observed up to a 1:200,000 dilution. nHRP2 yield from HB3 culture by bead-based immunoassay revealed that both culture supernatant and iRBC lysate were practical sources of large quantities of this antigen, producing a total yield of 292.4 µg of nHRP2 from two pooled culture preparations. Assessment of nHRP2 recognition by RDTs revealed that Carestart Pf HRP2 and HRP2/pLDH RDTs detected purified nHRP2 when applied at concentrations between 20.6 to 2060 ng/mL, performing within a log-fold dilution of commercially-available recombinant HRP2. The band intensity observed for the nHRP2 dilutions was equivalent to that observed for P. falciparum culture strain dilutions of 3D7 and US06 F Nigeria XII between 12.5 and 1,000 parasites/µl.Conclusions: Purified nHRP2 could be a valuable reagent for laboratory applications as well as assessment of new and existing RDTs prior to their use in clinical settings. These results establish that it is possible to extract microgram quantities of the native HRP2 antigen from HB3 culture and that this purified protein is well recognized by existing monoclonal antibody lines and RDTs.

The Anticoagulant Properties of a Modified Form of Protein S

1988 ◽  
Vol 60 (02) ◽  
pp. 298-304 ◽  
Author(s):  
C A Mitchell ◽  
S M Kelemen ◽  
H H Salem
Keyword(s):  
Monoclonal Antibody ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Factor Xa ◽  
Protein S ◽  
Human Neutrophil Elastase ◽  
Factor X ◽  
Sds Page

SummaryProtein S (PS) is a vitamin K-dependent anticoagulant that acts as a cofactor to activated protein C (APC). To date PS has not been shown to possess anticoagulant activity in the absence of APC.In this study, we have developed monoclonal antibody to protein S and used to purify the protein to homogeneity from plasma. Affinity purified protein S (PSM), although identical to the conventionally purified protein as judged by SDS-PAGE, had significant anticoagulant activity in the absence of APC when measured in a factor Xa recalcification time. Using SDS-PAGE we have demonstrated that prothrombin cleavage by factor X awas inhibited in the presence of PSM. Kinetic analysis of the reaction revealed that PSM competitively inhibited factor X amediated cleavage of prothrombin. PS preincubated with the monoclonal antibody, acquired similar anticoagulant properties. These results suggest that the interaction of the monoclonal antibody with PS results in an alteration in the protein exposing sites that mediate the observed anticoagulant effect. Support that the protein was altered was derived from the observation that PSM was eight fold more sensitive to cleavage by thrombin and human neutrophil elastase than conventionally purified protein S.These observations suggest that PS can be modified in vitro to a protein with APC-independent anticoagulant activity and raise the possibility that a similar alteration could occur in vivo through the binding protein S to a cellular or plasma protein.

Biochemical characterization of Plasmodium falciparum CTP:phosphoethanolamine cytidylyltransferase shows that only one of the two cytidylyltransferase domains is active

2013 ◽  
Vol 450 (1) ◽  
pp. 159-167 ◽  
Author(s):  
Sweta Maheshwari ◽  
Marina Lavigne ◽  
Alicia Contet ◽  
Blandine Alberge ◽  
Emilie Pihan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cellular Localization ◽  
Biochemical Characterization ◽  
De Novo ◽  
Membrane Lipids ◽  
Polyclonal Antibodies ◽  
Homology Modelling ◽  
Site Directed Mutagenesis ◽  
Recombinant Enzymes ◽  
Parasite Life Cycle

The intra-erythrocytic proliferation of the human malaria parasite Plasmodium falciparum requires massive synthesis of PE (phosphatidylethanolamine) that together with phosphatidylcholine constitute the bulk of the malaria membrane lipids. PE is mainly synthesized de novo by the CDP:ethanolamine-dependent Kennedy pathway. We previously showed that inhibition of PE biosynthesis led to parasite death. In the present study we characterized PfECT [P. falciparum CTP:phosphoethanolamine CT (cytidylyltransferase)], which we identified as the rate-limiting step of the PE metabolic pathway in the parasite. The cellular localization and expression of PfECT along the parasite life cycle were studied using polyclonal antibodies. Biochemical analyses showed that the enzyme activity follows Michaelis–Menten kinetics. PfECT is composed of two CT domains separated by a linker region. Activity assays on recombinant enzymes upon site-directed mutagenesis revealed that the N-terminal CT domain was the only catalytically active domain of PfECT. Concordantly, three-dimensional homology modelling of PfECT showed critical amino acid differences between the substrate-binding sites of the two CT domains. PfECT was predicted to fold as an intramolecular dimer suggesting that the inactive C-terminal domain is important for dimer stabilization. Given the absence of PE synthesis in red blood cells, PfECT represents a potential antimalarial target opening the way for a rational conception of bioactive compounds.

scholarly journals BACTERIAL AGGLUTINATION BY A LECTIN FROM THE LEAVES OF THE MEDICINAL PLANT, PIMENTA DIOICA (L.) MERR

2018 ◽  
Vol 10 (4) ◽  
pp. 35 ◽  
Author(s):  
Surya P H ◽  
Elyas K K ◽  
Deepti Madayi
Keyword(s):  
Escherichia Coli ◽  
Medicinal Plant ◽  
Biochemical Characterization ◽  
Exchange Chromatography ◽  
Bacterial Typing ◽  
Gram Negative ◽  
Sds Page ◽  
Bacterial Filters ◽  
Pimenta Dioica ◽  
Bacterial Agglutination

Objective: The current investigation involves the purification, characterization of the lectin from the leaves of Pimenta dioica (L.) Merr. (Myrtaceae) a medicinal plant, and its application in bacterial typing.Methods: A lectin was purified from the leaves by cation exchange chromatography. SDS PAGE revealed the molecular weight of the purified lectin. Biochemical characterization was carried out by performing various tests. Hemagglutination inhibition was conducted to detect the sugar specificity. Additionally, bacterial agglutination was performed to predict whether the purified lectin was able to agglutinate the bacterial strains.Results: SDS PAGE analysis revealed the lectin to be a tetramer in the range of 43-66 kDa. The purified lectin agglutinated human, avian, and mouse erythrocytes, and was inhibited by 125 mmol of mannose and xylose. The lectin was stable at 0-60 ° C for 30 min and was unaffected by either 2-Mercaptoethanol (2-ME) or Dithiothreitol (DTT) (50-250µM). A pH of 6.0–8.0 was found optimum for its activity and was nearly independent of metal ions. The purified lectin contained about 20% carbohydrate as estimated by Anthrone method. Purified lectin agglutinated the Gram-negative Escherichia coli and Proteus vulgaris.Conclusion: The isolated lectin was found to possess significant hemagglutinating activity. Due to its ability to agglutinate Gram negative bacteria such as Escherichia coli and Proteus vulgaris, it could be used for bacterial typing and for the design of bacterial filters.

scholarly journals Production and characterization of monoclonal antibodies to the edta extract of Leptospira interrogans, serovar icterohaemorrhagiae

1996 ◽  
Vol 29 (5) ◽  
pp. 483-489
Author(s):  
Lilian Terezinha de Queiroz Leite ◽  
Mauricio Resende ◽  
Wanderley de Souza ◽  
Elizabeth R.S. Camargos ◽  
Matilde Cota Koury
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Western Blot ◽  
Silver Staining ◽  
Colloidal Gold ◽  
Leptospira Interrogans ◽  
Outer Envelope ◽  
Lethal Challenge ◽  
Sds Page

Monoclonal antibodies (MABs) ivere produced against an etbylenediaminetetraacetate (EDTA) extract of Leptospira interrogans serovar icterohaemorrhagiae being characterized by gel precipitation as IgM and IgG (IgGl and IgG2b). The EDTA extract was detected as several bands by silver staining in SDS-PAGE. In the Western blot the bands around 20 KDa reacted with a monoclonal antibody, 47B4D6, and was oxidized by periodate and was not digested by pronase, suggesting that the determinant is of carbohydrate nature, lmmunocytochemistry, using colloidal gold labeling, showed that an EDTA extract determinant recognized by monoclonal antibody 47B4D6, is localized under the outer envelope of serovar icterohaemorrhagiae. Hoe AIAB raised against the EDTA extract was not able to protect hamsters from lethal challenge with virulent homologous leptospires.

scholarly journals Immunohistochemical and immunochemical characterization of a new endothelial cell-specific antigen.

1986 ◽  
Vol 34 (2) ◽  
pp. 209-214 ◽  
Author(s):  
J U Alles ◽  
K Bosslet
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Specific Antigen ◽  
Similar Molecular Weight ◽  
Immunochemical Characterization ◽  
Sds Page

A new monoclonal antibody (moab BW 200) of IgG3 kappa-isotype was generated which recognizes an epitope located on an antigen molecule restricted to human neoplastic and non-neoplastic endothelial cells. The molecular weight of the antigen was determined using immunoprecipitation analysis followed by SDS-PAGE. Despite its similar molecular weight to FVIII-RAG, the antigen detected by moab BW 200 was shown to be different from FVIII-RAG.

scholarly journals Generating and characterizing the anti-human CD45 monoclonal antibody

2020 ◽  
Vol 23 (3) ◽  
pp. 665-672
Author(s):  
Giang Huong Ta ◽  
Huy Quoc Nguyen ◽  
Quan Dang Nguyen
Keyword(s):  
Monoclonal Antibody ◽  
Western Blotting ◽  
Jurkat Cells ◽  
Spleen Cells ◽  
Myeloma Cells ◽  
E Coli ◽  
Common Marker ◽  
Sds Page ◽  
Hybridoma Technology ◽  
Mab Production

Introduction: CD45 is a common marker of leukocytes. Anti-human CD45 monoclonal antibody (MAb) has been used widely in diagnosing and monitoring hematologic diseases. The aim of this study was to generate an anti-human CD45 MAb, which can be used in research and diagnosis. Methods: Recombinant human CD45RO antigen was expressed from E. coli BL21 (DE3), purified and analyzed by SDS-PAGE and Western blotting. The purified CD45RO antigen was used to immunize Balb/c mice. Spleen cells from immunized mouse were collected and fused with P3X63Ag8.653 myeloma cells to form hybridoma. Anti-CD45 antibody-secreting capacity of hybridoma clones was evaluated by ELISA assay. Anti-CD45 MAb from the culture supernatant of the chosen hybridoma clone was purified by affinity chromatography. The MAb was characterized the biochemical characteristics and biological activity. Results: Recombinant human CD45RO antigen was expressed and purified from E.coli BL21 (DE3). Injection of purified CD45RO antigen provoked the immune response in Balb/c mice. Hybridoma clones were generated successfully by the fusion of spleen cells from the selected immunized-mouse and myeloma cells. Among these hybridoma clones, one with the highest yield of MAb production was identified. The isotype of the anti-CD45 MAb created in this work is IgG2b, while its the light chain is kappa (k) type. The affinity of this MAb with CD45RO antigen is high with Kd value at the picomolar level. The anti-CD45 MAb can interact with CD45 naturally expressed on the surface of Jurkat cells in Western blotting and fluorescent immuno-staining assay. Conclusion: We have developed successfully an anti-human CD45 MAb using hybridoma technology, which can recognize CD45 in ELISA, Western blotting, and fluorescent immuno-staining analysis. Although further investigations are necessary, obviously, our anti-human CD45 MAb is potential for research and diagnosis applications.

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