scholarly journals Structural and immunological characterization of an epitope within the PAN motif of ectodomain I in Babesia bovis apical membrane antigen 1

2020 ◽  
Author(s):  
Amarin Rittipornlertrak ◽  
Boondarika Nambooppha ◽  
Anucha Muenthaisong ◽  
Veerasak Punyapornwithaya ◽  
Saruda Tiwananthagorn ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Apical Membrane ◽  
Cell Epitope ◽  
Babesia Bovis ◽  
Target Antigen ◽  
Bovine Babesiosis ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Domain I

Abstract Background Bovine babesiosis caused by Babesia bovis (B. bovis) affects the cattle industry worldwide with high mobility and mortality. Live-attenuated vaccines are currently used in some of the endemic countries, but their wide use is limited due to various reasons. Although recombinant vaccines have been proposed as an alternative to the live vaccines, such vaccines are not commercially available to date. Apical membrane antigen-1 (AMA-1) is one of the leading candidates for vaccine development against diseases caused by apicomplexan parasite species. In this study, we predicted an epitope from the plasminogen, apple and nematode (PAN) motif of domain I in the B. bovis AMA-1 (BbAMA-1) using a combination of linear and conformational B-cell epitope prediction software. The selected epitope was bioinformatically analyzed, synthesized as a peptide (sBbAMA-1), and then used to immunize a rabbit. Results The anti-sBbAMA-1 serum obtained was evaluated for its growth- and invasion-inhibitory effects on B. bovis merozoites in vitro. Our results demonstrated that the predicted BbAMA-1 epitope, which is located on surface-exposed α-helix of PAN motif in domain I at the apex area, elicits antibodies capable of recognizing the native BbAMA-1 in immunoassays. Importantly, as compared to the control groups, the rabbit anti-sBbAMA-1 serum at dilution of 1:5 significantly inhibited (p < 0.05) the growth of B. bovis merozoites by approximately 50–70% on day 3 and 4 of cultivation and the invasion of merozoites by approximately 60% within 4 h of incubation. Conclusion Our results indicate the epitope predicted from the PAN motif of BbAMA-1 domain I is neutralization-sensitive and may serve as a target antigen for vaccine development against bovine babesiosis caused by B. bovis.

scholarly journals Structural and immunological characterization of an epitope within the PAN motif of ectodomain I in Babesia bovis apical membrane antigen 1 for vaccine development

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11765
Author(s):  
Amarin Rittipornlertrak ◽  
Boondarika Nambooppha ◽  
Anucha Muenthaisong ◽  
Veerasak Punyapornwithaya ◽  
Saruda Tiwananthagorn ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Apical Membrane ◽  
Rabbit Antiserum ◽  
Babesia Bovis ◽  
Inhibitory Effects ◽  
Bovine Babesiosis ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Domain I

Background Bovine babesiosis caused by Babesia bovis (B. bovis) has had a significant effect on the mobility and mortality rates of the cattle industry worldwide. Live-attenuated vaccines are currently being used in many endemic countries, but their wide use has been limited for a number of reasons. Although recombinant vaccines have been proposed as an alternative to live vaccines, such vaccines are not commercially available to date. Apical membrane antigen-1 (AMA-1) is one of the leading candidates in the development of a vaccine against diseases caused by apicomplexan parasite species. In Plasmodium falciparum (P. falciparum) AMA-1 (PfAMA-1), several antibodies against epitopes in the plasminogen, apple, and nematode (PAN) motif of PfAMA-1 domain I significantly inhibited parasite growth. Therefore, the purpose of this study was to predict an epitope from the PAN motif of domain I in the B. bovis AMA-1 (BbAMA-1) using a combination of linear and conformational B-cell epitope prediction software. The selected epitope was then bioinformatically analyzed, synthesized as a peptide (sBbAMA-1), and then used to immunize a rabbit. Subsequently, in vitro growth- and the invasion-inhibitory effects of the rabbit antiserum were immunologically characterized. Results Our results demonstrated that the predicted BbAMA-1 epitope was located on the surface-exposed α-helix of the PAN motif in domain I at the apex area between residues 181 and 230 with six polymorphic sites. Subsequently, sBbAMA-1 elicited antibodies capable of recognizing the native BbAMA-1 in immunoassays. Furthermore, anti-serum against sBbAMA-1 was immunologically evaluated for its growth- and invasion-inhibitory effects on B. bovis merozoites in vitro. Our results demonstrated that the rabbit anti-sBbAMA-1 serum at a dilution of 1:5 significantly inhibited (p < 0.05) the growth of B. bovis merozoites by approximately 50–70% on days 3 and 4 of cultivation, along with the invasion of merozoites by approximately 60% within 4 h of incubation when compared to the control groups. Conclusion Our results indicate that the epitope predicted from the PAN motif of BbAMA-1 domain I is neutralization-sensitive and may serve as a target antigen for vaccine development against bovine babesiosis caused by B. bovis.

scholarly journals Specificity of the Protective Antibody Response to Apical Membrane Antigen 1

2001 ◽  
Vol 69 (5) ◽  
pp. 3286-3294 ◽  
Author(s):  
Anthony N. Hodder ◽  
Pauline E. Crewther ◽  
Robin F. Anders
Keyword(s):  
Apical Membrane ◽  
Affinity Purification ◽  
Point Mutations ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Potential Vaccine ◽  
Inhibitory Antibodies ◽  
Domain I ◽  
The Impact

ABSTRACT Apical membrane antigen 1 (AMA1) is considered one of the leading candidates for inclusion in a vaccine against blood stages ofPlasmodium falciparum. Although the ama1 gene is relatively conserved compared to those for some other potential vaccine components, numerous point mutations have resulted in amino acid substitutions at many sites in the polypeptide. The polymorphisms in AMA1 have been attributed to the diversifying selection pressure of the protective immune responses. It was therefore of interest to investigate the impact of sequence diversity in P. falciparum AMA1 on the ability of anti-AMA1 antibodies to inhibit the invasion of erythrocytes in vitro by P. falciparummerozoites. For these studies, we used antibodies to recombinantP. falciparum 3D7 AMA1 ectodomain, which was prepared for testing in early clinical trials. Antibodies were raised in rabbits to the antigen formulated in Montanide ISA720, and human antibodies to AMA1 were isolated by affinity purification from the plasma of adults living in regions of Papua New Guinea where malaria is endemic. Both rabbit and human anti-AMA1 antibodies were found to be strongly inhibitory to the invasion of erythrocytes by merozoites from both the homologous and two heterologous lines of P. falciparum. The inhibitory antibodies targeted both conserved and strain-specific epitopes within the ectodomain of AMA1; however, it appears that the majority of these antibodies reacted with strain-specific epitopes in domain I, the N-terminal disulfide-bonded domain, which is the most polymorphic region of AMA1.

scholarly journals In Immunization with Plasmodium falciparum Apical Membrane Antigen 1, the Specificity of Antibodies Depends on the Species Immunized

2007 ◽  
Vol 75 (12) ◽  
pp. 5827-5836 ◽  
Author(s):  
Kazutoyo Miura ◽  
Hong Zhou ◽  
Olga V. Muratova ◽  
Andrew C. Orcutt ◽  
Birgitte Giersing ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Vaccine Development ◽  
Apical Membrane ◽  
Rabbit Model ◽  
Enzyme Linked Immunosorbent Assay ◽  
Allelic Polymorphism ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

ABSTRACT At least a million people, mainly African children under 5 years old, still die yearly from malaria, and the burden of disease and death has increased. Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is one of the most promising blood-stage malarial vaccine candidates. However, the allelic polymorphism observed in this protein is a potential stumbling block for vaccine development. To overcome the polymorphism- and strain-specific growth inhibition in vitro, we previously showed in a rabbit model that vaccination with a mixture of two allelic forms of PfAMA1 induced parasite growth-inhibitory antisera against both strains of P. falciparum parasites in vitro. In the present study, we have established that, in contrast to a single-allele protein, the antigen mixture elicits primarily antibodies recognizing antigenic determinants common to the two antigens, as judged by an antigen reversal growth inhibition assay (GIA). We also show that a similar reactivity pattern occurs after immunization of mice. By contrast, sera from rhesus monkeys do not distinguish the two alleles when tested by an enzyme-linked immunosorbent assay or by GIA, regardless of whether the immunogen is a single AMA1 protein or the mixture. This is the first report that a malarial vaccine candidate induced different specificities of functional antibodies depending on the animal species immunized. These observations, as well as data available on human immune responses in areas of endemicity, suggest that polymorphism in the AMA1 protein may not be as formidable a problem for vaccine development as anticipated from studies with rabbits and mice.

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.

scholarly journals Identification of a Highly Antigenic Linear B Cell Epitope within Plasmodium vivax Apical Membrane Antigen 1 (AMA-1)

PLoS ONE ◽  
2011 ◽  
Vol 6 (6) ◽  
pp. e21289 ◽  
Author(s):  
Lilian Lacerda Bueno ◽  
Francisco Pereira Lobo ◽  
Cristiane Guimarães Morais ◽  
Luíza Carvalho Mourão ◽  
Ricardo Andrez Machado de Ávila ◽  
...  
Keyword(s):  
B Cell ◽  
Plasmodium Vivax ◽  
Apical Membrane ◽  
Cell Epitope ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
B Cell Epitope ◽  
Linear B

scholarly journals A Diversity-Covering Approach to Immunization with Plasmodium falciparum Apical Membrane Antigen 1 Induces Broader Allelic Recognition and Growth Inhibition Responses in Rabbits

2008 ◽  
Vol 76 (6) ◽  
pp. 2660-2670 ◽  
Author(s):  
Edmond J. Remarque ◽  
Bart W. Faber ◽  
Clemens H. M. Kocken ◽  
Alan W. Thomas
Keyword(s):  
Plasmodium Falciparum ◽  
Amino Acid ◽  
Growth Inhibition ◽  
Apical Membrane ◽  
Recombinant Expression ◽  
Methylotrophic Yeast ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Amino Acid Variability

ABSTRACT Plasmodium falciparum apical membrane antigen 1 (PfAMA1), a candidate malaria vaccine, is polymorphic. This polymorphism is believed to be generated predominantly under immune selection pressure and, as a result, may compromise attempts at vaccination. Alignment of 355 PfAMA1 sequences shows that around 10% of the 622 amino acid residues can vary between alleles and that linkages between polymorphic residues occur. Using this analysis, we have designed three diversity-covering (DiCo) PfAMA1 sequences that take account of these linkages and, when taken together, on average incorporate 97% of amino acid variability observed. For each of the three DiCo sequences, a synthetic gene was constructed and used to transform the methylotrophic yeast Pichia pastoris, allowing recombinant expression. All three DiCo proteins were reactive with the reduction-sensitive monoclonal antibody 4G2, suggesting the DiCo sequences had conformations similar to those of naturally occurring PfAMA1. Rabbits were immunized with FVO strain PfAMA1 or with the DiCo proteins either individually or as a mixture. Antibody titers and the ability to inhibit parasite growth in vitro were determined. Animals immunized with the DiCo mix performed similarly to animals immunized with FVO AMA1 when measured against FCR3 strain parasites but outperformed animals immunized with FVO AMA1 when assessed against other strains. The levels of growth inhibition (∼70%) induced by the mix of three DiCo proteins were comparable for FVO, 3D7, and HB3, suggesting that a considerable degree of diversity in AMA1 is adequately covered. This suggests that vaccines based upon the DiCo mix approach provide a broader functional immunity than immunization with a single allele.

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