High-Level Expression, Purification and Characterization of A Recombinant Plasmodium vivax Apical Membrane Antigen 1: Implication for vivax Malaria Vaccine Development
Objective: The apical membrane antigen-1 (AMA-1) is considered as a promising candidate for development of a malaria vaccine against Plasmodium parasites. The correct conformation of this protein appears to be necessary for the stimulation of parasite-inhibitory responses, and these responses, in...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Royan Institute (ACECR), Tehran
2015-10-01
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| Series: | Cell Journal |
| Subjects: | |
| Online Access: | http://celljournal.org/web/journal/article/988/download |
| Summary: | Objective: The apical membrane antigen-1 (AMA-1) is considered as a promising candidate
for development of a malaria vaccine against Plasmodium parasites. The correct
conformation of this protein appears to be necessary for the stimulation of parasite-inhibitory
responses, and these responses, in turn, seem to be antibody-mediated. Therefore, in
the present investigation, we expressed the Plasmodium vivax AMA-1 (PvAMA-1) ectodomain
in Escherichia coli (E. coli), purified it using standard procedures and characterized
it to determine its biological activities for it to be used as a potential target for developing
a protective and safe vivax malaria vaccine.
Materials and Methods: In this experimental investigation, the ectodomain of PvAMA-
1 antigen (GenBank accession no. JX624741) was expressed in the E. coli M15-
pQE30 expression system and purified with immobilized-metal affinity chromatography.
The correct conformation of the recombinant protein was evaluated by Western
blotting and indirect immunofluorescence antibody (IFA) test. In addition, the immunogenic
properties of PvAMA-1 were evaluated in BALB/c mice with the purified protein
emulsified in Freund’s adjuvant.
Results: In the present study, the PvAMA-1 ectodomain was expressed at a high-level
(65 mg/L) using a bacterial system. Reduced and non-reduced sodium dodecyl sulfate-
polyacrylamide gel electrophoresis (SDS-PAGE) as well as Western blot analysis
confirmed the appropriate conformation and folding of PvAMA-1. The evaluation of
immunogenic properties of PvAMA-1 showed that both T helper-1 and 2 cells (Th1
and Th2) responses were present in mice after three immunizations and persisted up
to one year after the first immunization. Moreover, the antibodies raised against the
recombinant PvAMA-1 in injected mice could recognize the native protein localized on
P. vivax parasites.
Conclusion: We demonstrate that our recombinant protein had proper conformation
and folding. Also, there were common epitopes in the recombinant forms corresponding
to native proteins. These results; therefore, indicate that the expressed PvAMA-1
has the potential to be used as a vivax malaria vaccine. |
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| ISSN: | 2228-5806 2228-5814 |