Humoral Response against Native Plasmodium berghei Hemozoin and Synthetic Hemozoin in BALB/c Mice

Aims: Malaria is a disease caused by protozoan parasites of the genus Plasmodium. One of the malaria mechanisms of adaptation to the host is the digestion of hemoglobin by the trophozoite stage. This mechanism provides the amino acids needed by the parasite and is carried out during the erythrocytics schozogony phase, which results in the formation of in soluble pigment crystals named hemozoin (Hz). Hz is responsible for many of the immune pathological complications of malaria, given that this pigment accumulates in various organs in severe cases of the disease.
Here, we evaluated the humoral response in BALB/c mice against native Plasmodium berghei Hz (PbHz) and synthetic Hz (SHz).
Place and Duration of Study: Laboratory of Immunology of Infection Diseases. Department of Cell Biology, Simón Bolívar University, Caracas, Venezuela. This study was performed between January 2012 and June 2012.
Methodology: We determined the humoral response of SHz and PbHz by an enzyme linked immunosorbent assay (ELISA), using hyper-immune sera from mice experimentally infected with P. berghei or Plasmodium yoelii. In addition, SHz was evaluated as antigen by Western Blot and dot-ELISA.
Results: When SHz was employed as antigen, we showed by indirect ELISA that the sera from mice immunized with SHz generated higher titers than sera obtained from mice infected with either Plasmodium species. Moreover, the sera from human infections also recognized SHz as antigen, but showed a better recognition by dot- ELISA or Western Blot than by indirect ELISA.
Conclusion: In summary, our results indicated that SHz can be used as a rapid and successful diagnostic antigen for natural malaria infections by indirect ELISA, dot-ELISA and Western Blot techniques.