Malaria Ab
Enzyme Immunoassay (ELISA) for the determination of antibodies to Plasmodium species in human sera and plasma. The kit is intended for the screening of blood units and the identification of people that came into contact with the protozoa and developed an immunological response.
Plasmodium species are obligate intracellular protozoa related to Babesia and Toxoplasma. Plasmodium species reproduce sexually in mosquitoes; mosquitoes transmit the resulting sporozoites into humans where the organisms reproduce asexually. The sporozoites multiply within the liver; resulting merozoites invade erythrocytes where the merozoites multiply or mature into male and female gametocytes which eventually will be taken up by a mosquito during a blood meal.
P.falciparum and P.vivax cause approximately 80% and 15%, respectively, of all cases of Malaria.
Malaria is the most severe infectious disease of tropical and subtropical areas of the world that still is heavily affecting millions of people and generating millions of casualties.
The detection of anti P.species antibodies can identify in suspected individuals a case of recent or past malaria.
Recombinant proteins representing immunodominant epitopes of Plasmodium species, are coated onto wells of a microplate.
Recombinant proteins have been carefully selected to ensure the screening of all antibodies to P.species. Serum or plasma samples are added to these wells and, if antibodies specific to P.species (IgG, IgM or IgA) are present in the sample, they will form stable complexes with the recombinant antigens in the well.
Antigen-antibody complexes are then identified through the successive addition of: (1) same biotinylated recombinant proteins specific to P.species and; (2) horseradish peroxidase HRP Streptavidin conjugate.
The hydrolytic activity of horseradish peroxidase allows for the quantification of these antibody-antigen complexes. Peroxidase substrate solution is then added.
During incubation, a blue colour will develop in proportion to the amount of anti P.species antibodies bound to the well, thus establishing their presence or absence in the sample. Wells containing samples negative for anti-P.species antibody remain colourless.
A stop solution is added to each well and the resulting yellow colour is read on a microplate reader at 450 nm.
- Garcia LS et al. Update on Malaria. Clin Microbiol News Lett; 1992, 14:65-9
- Krogstad DJ et al. Plasmodium species (Malaria) principles and practice of infectious diseases, 4th ed, MandellGL et al., 1995, 2415-27.
- Smith JH et al. Malaria: clinical laboratory features. Clin Microbiol News Lett, 1995,17(24): 185-8.