scholarly journals Natural Human Antibody Responses to Plasmodium vivax Apical Membrane Antigen 1 under Low Transmission and Unstable Malaria Conditions in Sri Lanka

2006 ◽  
Vol 74 (1) ◽  
pp. 798-801 ◽  
Author(s):  
Thilan Wickramarachchi ◽  
Prasad H. Premaratne ◽  
K. L. R. Lakshman Perera ◽  
Sumith Bandara ◽  
Clemens H. M. Kocken ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Plasmodium Vivax ◽  
Malaria Vaccine ◽  
Apical Membrane ◽  
Human Antibody ◽  
Antibody Prevalence ◽  
Low Transmission ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Malaria Vaccine Candidate

ABSTRACT Plasmodium vivax apical membrane antigen 1, an important malaria vaccine candidate, was immunogenic during natural malaria infections in Sri Lanka, where low transmission and unstable malaria conditions prevail. Antibody prevalence increased with exposure in areas where malaria was or was not endemic. A marked isotype switch to cytophilic (immunoglobulin G1 [IgG1]/IgG3) antibodies was evident with increasing exposure exclusively in residents from areas of endemicity.

Evaluation of the genetic diversity of domain II of Plasmodium vivax Apical Membrane Antigen 1 (PvAMA-1) and the ensuing strain-specific immune responses in patients from Sri Lanka

Vaccine ◽  
2011 ◽  
Vol 29 (43) ◽  
pp. 7491-7504 ◽  
Author(s):  
Sajani Dias ◽  
Maheshika Somarathna ◽  
Aresha Manamperi ◽  
Ananias A. Escalante ◽  
Anusha M. Gunasekera ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Sri Lanka ◽  
Immune Responses ◽  
Plasmodium Vivax ◽  
Apical Membrane ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen

scholarly journals Apical Membrane Antigen 1, a Major Malaria Vaccine Candidate, Mediates the Close Attachment of Invasive Merozoites to Host Red Blood Cells

2004 ◽  
Vol 72 (1) ◽  
pp. 154-158 ◽  
Author(s):  
G. H. Mitchell ◽  
A. W. Thomas ◽  
G. Margos ◽  
A. R. Dluzewski ◽  
L. H. Bannister
Keyword(s):  
Malaria Vaccine ◽  
Vaccine Candidate ◽  
Apical Membrane ◽  
Plasmodium Knowlesi ◽  
Red Cells ◽  
Red Cell ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Malaria Vaccine Candidate ◽  
Candidate Molecule

ABSTRACT Apical membrane antigen 1 (AMA-1) of Plasmodium merozoites is established as a candidate molecule for inclusion in a human malaria vaccine and is strongly conserved in the genus. We have investigated its function in merozoite invasion by incubating Plasmodium knowlesi merozoites with red cells in the presence of a previously described rat monoclonal antibody (MAb R31C2) raised against an invasion-inhibitory epitope of P. knowlesi AMA-1 and then fixing the material for ultrastructural analysis. We have found that the random, initial, long-range (12 nm) contact between merozoites and red cells occurs normally in the presence of the antibody, showing that AMA-1 plays no part in this stage of attachment. Instead, inhibited merozoites fail to reorientate, so they do not bring their apices to bear on the red cell surface and do not make close junctional apical contact. We conclude that AMA-1 may be directly responsible for reorientation or that the molecule may initiate the junctional contact, which is then presumably dependent on Duffy binding proteins for its completion.

scholarly journals Phase 1/2a Study of the Malaria Vaccine Candidate Apical Membrane Antigen-1 (AMA-1) Administered in Adjuvant System AS01B or AS02A

PLoS ONE ◽  
2009 ◽  
Vol 4 (4) ◽  
pp. e5254 ◽  
Author(s):  
Michele D. Spring ◽  
James F. Cummings ◽  
Christian F. Ockenhouse ◽  
Sheetij Dutta ◽  
Randall Reidler ◽  
...  
Keyword(s):  
Malaria Vaccine ◽  
Vaccine Candidate ◽  
Apical Membrane ◽  
Phase 1 ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Adjuvant System ◽  
Malaria Vaccine Candidate

scholarly journals Functional Analysis of Plasmodium falciparum Apical Membrane Antigen 1 Utilizing Interspecies Domains

2005 ◽  
Vol 73 (4) ◽  
pp. 2444-2451 ◽  
Author(s):  
Julie Healer ◽  
Tony Triglia ◽  
Anthony N. Hodder ◽  
Alan W. Gemmill ◽  
Alan F. Cowman
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Vaccine ◽  
Apical Membrane ◽  
Parasite Line ◽  
Apical Membrane Antigen 1 ◽  
Apical Membrane Antigen ◽  
Erythrocyte Invasion ◽  
Malaria Vaccine Candidate ◽  
Domain Iii ◽  
Dominant Epitope

ABSTRACT Plasmodium falciparum apical membrane antigen 1 (AMA1) is a leading malaria vaccine candidate whose function has not been unequivocally defined. Partial complementation of function can be achieved by exchanging the AMA1 of P. falciparum (PfAMA1) with that of P. chabaudi (PcAMA1). In this study, parasites expressing chimeric AMA1 proteins were created to identify domains of PfAMA1 critical in erythrocyte invasion and which are important immune targets. We report that specific chimeric AMA1 proteins containing domains I to III from PfAMA1 and PcAMA1 were able to complement PfAMA1 function in erythrocyte invasion. We demonstrate that domain III does not contain dominant epitope targets of antibodies raised against Escherichia coli expressed and refolded PfAMA1 ectodomain. Furthermore, we generated a parasite line in which the N-terminal pro region of PfAMA1 does not undergo proteolytic cleavage and show that its removal is necessary for PfAMA1 function.

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