Peptides of the liver stage antigen-1 (LSA-1) of Plasmodium falciparum bind to human hepatocytes.
ABSTRACT Synthetic peptides from the liver stage antigen-1 (LSA-1) antigen sequence were used in HepG2 cell and erythrocyte binding assays to identify regions that could be involved in parasite invasion. LSA-1 protein peptides 20630 ((21)INGKIIKNSEKDEIIKSNLRY(40)), 20637 ((157)KEKLQGQQSDSEQERRAY(173)), 20638 ((174)KEKLQEQQSDLEQERLAY(190)) and 20639 (191KEKLQEQQSDLEQERRAY(207)) had high binding activity in HepG2 assays. Were located in immunogenic regions; peptide cell binding was saturable. Peptide 20630 bound specifically to 48kDa HepG2 membrane surface protein. LSA-1 peptides 20630 ((21)INGKIIKNSEKDEIIKSNLRY(40)) and 20633 ((81)DKELTMSNVKNVSQTNFKSLY(100)) showed specific erythrocyte binding activity and inhibited merozoite invasion of erythrocytes in vitro. A monkey serum prepared against LSA-1 20630 peptide analog (CGINGKNIKNAEKPMIIKSNLRGC) inhibited merozoite invasion in vitro. The data suggest LSA-1 "High Activity Binding Peptides" could play a possible role in hepatic cell invasion as well as merozoite invasion of erythrocytes.
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ABSTRACT: A fully effective antimalarial vaccine must contain multiple proteins from the different development stages of Plasmodium falciparum parasites involved in host-cell invasion or their biologically active fragments. It must therefore include sporozoite molecules able to induce protective immunity by blocking the parasite's access to hepatic cells, and/or proteins involved in the development of this stage, amongst which are included the Liver Stage Antigen-1 (LSA-1) and the Sporozoite and Liver Stage Antigen (SALSA). Our studies have focused on the search for an association between the structure of high activity binding peptides (HABPs), including both conserved native and their modified analogues, and their ability to bind to the MHC Class II HLA-DR molecules during formation of the MHCII-peptide-TCR complex leading to inducing the appropriate immune response. These studies are part of a logical and rational strategy for developing multi-stage, multi-component, minimal subunit-based vaccines, mainly against the P. falciparum malaria.Biochemical and Biophysical Research Communications 06/2009; 384(4):455-60. · 2.28 Impact Factor
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ABSTRACT: The identification and characterization of hypothetical membrane proteins from Mycobacterium tuberculosis have led to a better understanding of the mechanisms used by this pathogen to invade and survive inside host cells. This study assessed the presence, transcription, localization and possible biological activity of the conserved hypothetical protein Rv0180c from M. tuberculosis. Bioinformatics analyses indicated that Rv0180c contains a signal peptide, six possible transmembrane helices and a Plasmodium Export Element (PEXEL)-like motif. PCR analyses showed the presence of the Rv0180c gene in strains from the M. tuberculosis complex; but transcription was not detected in Mycobacterium microti. Sera against synthetic peptides of Rv0180c recognized two protein bands in M. tuberculosis H37Rv sonicate: a ∼48-kDa band close to the predicted molecular mass of Rv0180c (47.6 kDa), and a 63-kDa band probably caused by protein modifications. Moreover, the same sera located the protein on the surface of M. tuberculosis H37Rv bacilli by immunoelectron microscopy. Twenty-three synthetic peptides spanning the entire length of Rv0180c were tested for their ability to bind to U937 and A549 cells, finding nine high-activity binding peptides (HABPs) specific for both cell types, two HABPs specific for A549 cells (namely 31032 and 31044) and two HABPs specific for U937 cells (namely 31025 and 31041). HABPs inhibited invasion of M. tuberculosis H37Rv into A549 or U937 cells by significant percentages and facilitated internalization of latex beads in A549 cells. The Rv0180c HABPs herein reported could be preliminary candidates to be assessed as components of a multiepitope, chemically synthesized, subunit-based vaccine against tuberculosis.Peptides 09/2010; 32(1):1-10. · 2.61 Impact Factor
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ABSTRACT: Binding assays were carried out with 20 amino acid long peptides covering the complete 200-kDa Liver stage antigen (LSA) 3 protein sequence to identify its HepG2 cell binding regions. Seventeen HepG2 cell high-activity binding peptides (HABPs) were identified in the LSA-3 protein. Seven HABPs were found in the nonrepeat (NRA) region A; five of these formed a 100 amino acid long HepG2 cell binding region located between residues 21Ile and 120Thr. Six HABPs were found in the R2 region and another four in the NRB2 region. LSA-3 protein HABPS bound saturably to HepG2 cells having nanomolar affinity constants and bound specifically to 31, 44, and 70 kDa HepG2 cell membrane proteins. Some of them were located in antigenic and immunogenic LSA-3 protein regions. Immunofluorescence and immunoblotting assays using goat sera immunized with LSA-3 protein peptides recognized P. falciparum (FCB-2 strain) erythrocyte stage proteins (58, 68, 72, 81, 86, 160, and 175 kDa). This reactivity was due mainly to the VEESVAEN motif present in some erythrocyte stage proteins. However, our results suggest that antibodies against LSA-3 regions had a crossed reaction with another 86-kDa protein, and that this crossed reaction was due to a motif present in the NRA region.Journal of Molecular Medicine 10/2004; 82(9):600-11. · 4.74 Impact Factor
Peptides 24 (2003) 1453
Erratum to “Peptides of the liver stage antigen-1 (LSA-1) of
Plasmodium falciparum bind to human hepatocytes”
[Peptides 24 (2003) 647–657]?
Javier E. Garc´ ıa, Alvaro Puentes, Ramsés López, Ricardo Vera, Jorge Suárez, Luis Rodr´ ıguez,
Hernando Curtidor, Marisol Ocampo, Diana Tovar, Martha Forero, Adriana Bermudez,
Jimena Cortés, Mauricio Urquiza, Manuel E. Patarroyo∗
Fundación Instituto de Inmunolog´ ıa de Colombia, Universidad Nacional de Colombia, Bogotá, Colombia
The publisher regrets that errors occurred in Table 2 of the above article. The correct Table 2 follows:
LSA-1 protein high binding peptides and sera analogues invasion and development inhibition assays
% Invasion inhibition % Development inhibition
100?M 200?M 100?M 200?M
10 ± 4
48 ± 1
13 ± 2
100 ± 2
34 ± 2
88 ± 1
100 ± 2
100 ± 2
0 ± 3
15 ± 4
0 ± 5
100 ± 2
0 ± 3
85 ± 1
57 ± 2
100 ± 2
70 ± 5
8.8 ± 7
9.5 ± 5
100 ± 4
Peptides belonging to LSA-1 (20630 and 20633) inhibited in vitro merozoite invasion of erythrocytes. Peptide 20633 has the highest degree of inhibition
parasite invasion and development. Peptide 6762 was used as positive control. As shown, of the two sera assayed, one monkey 11 sera, inhibited invasion by
70%, whilst the other two behaved as did the control.
?doi of original article 10.1016/S0196-9781(03)00135-9.
∗Corresponding author. Tel.: +57-1-4815219/3158919; fax: +57-1-4815269.
E-mail addresses: email@example.com (J.E. Garc´ ıa), firstname.lastname@example.org (M.E. Patarroyo).
0196-9781/$ – see front matter © 2003 Elsevier Inc. All rights reserved.