Korean J Parasitol.  2012 Mar;50(1):15-21. 10.3347/kjp.2012.50.1.15.

A Recombinant Plasmodium vivax Apical Membrane Antigen-1 to Detect Human Infection in Iran

• Motevalli Haghi A
• Khoramizade MR
• Nateghpour M
• Mohebali M
• Edrissian
• Eshraghian MR
• Sepehrizadeh Z

• KMID: 1364890
• DOI: http://doi.org/10.3347/kjp.2012.50.1.15

Abstract

In Iran, Plasmodium vivax is responsible for more than 80% of the infected cases of malaria per year. Control interventions for vivax malaria in humans rely mainly on developed diagnostic methods. Recombinant P. vivax apical membrane antigen-1 (rPvAMA-1) has been reported to achieve designing rapid, sensitive, and specific molecular diagnosis. This study aimed to perform isolation and expression of a rPvAMA-1, derived from Iranian patients residing in an endemic area. Then, the diagnostic efficiency of the characterized Iranian PvAMA-1 was assessed using an indirect ELISA method. For this purpose, a partial region of AMA-1 gene was amplified, cloned, and expressed in pET32a plasmid. The recombinant His-tagged protein was purified and used to coat the ELISA plate. Antibody detection was assessed by indirect ELISA using rPvAMA-1. The validity of the ELISA method for detection of anti-P. vivax antibodies in the field was compared to light microscopy on 84 confirmed P. vivax patients and compared to 84 non-P. vivax infected individuals. The ELISA cut-off value was calculated as the mean+2SD of OD values of the people living in malaria endemic areas from a south part of Iran. We found a cut-off point of OD=0.311 that showed the best correlation between the sera confirmed with P. vivax infection and healthy control sera. A sensitivity of 81.0% and specificity of 84.5% were found at this cut off titer. A good degree of statistical agreement was found between ELISA using rPvAMA-1 and light microscopy (0.827) by Kappa analysis.

Keyword

Plasmodium vivax; AMA-1; recombinant antigen; ELISA; microscopy; Iran

MeSH Terms

Antibodies, Protozoan/blood/immunology
Antigens, Protozoan/*blood/genetics/immunology
Diagnostic Tests, Routine/*methods
Enzyme-Linked Immunosorbent Assay/*methods
Female
Humans
Iran
Malaria, Vivax/blood/*diagnosis/immunology/*parasitology
Male
Membrane Proteins/blood/genetics/immunology
Plasmodium vivax/isolation & purification/*physiology
Protozoan Proteins/blood/genetics/immunology
Sensitivity and Specificity