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Cross-reactive epitope among proteins in Plasmodium falciparum Maurer's clefts and primate leukocytes and platelets
F W Klotz1, S J Cohen, A Szarfman
1Department of Immunology, Walter Reed Army Institute of Research, Washington, District of Columbia, USA.
Abstract:
Erythrocytes infected with malaria parasites often contain membranous vesicles that are presumed to facilitate macromolecule traffic between the parasite and erythrocyte membranes. One such vesicle network, called Maurer's clefts, is expressed in Plasmodium falciparum-infected erythrocytes and contains a 50-kD polypeptide. Using a monoclonal antibody reactive with this polypeptide, we show that hepatic stages of P. falciparum express an epitope common to this blood-stage antigen. In addition, this epitope is cross-reactive with antigens expressed by primate leukocytes and platelets. Such epitopes may induce autoantibodies commonly seen in patients with malaria.
Insights
Malaria parasites create vesicles like Maurer's clefts in red blood cells. These structures share antigens with primate cells, potentially causing autoantibodies in malaria patients.
Area of Science:
- Malariology
- Immunology
- Cell Biology
Background:
- Erythrocytes infected with malaria parasites, specifically Plasmodium falciparum, develop membranous vesicles known as Maurer's clefts.
- Maurer's clefts are implicated in macromolecule transport between the parasite and the erythrocyte membrane.
- A specific 50-kD polypeptide is a known component of these clefts.
Purpose of the Study:
- To investigate the expression of a specific antigen associated with Maurer's clefts in different life stages of Plasmodium falciparum.
- To determine if this antigen cross-reacts with antigens found in primate leukocytes and platelets.
- To explore the potential role of this cross-reactivity in the development of autoantibodies in malaria patients.
Main Methods:
- Utilized a monoclonal antibody specific to a 50-kD polypeptide found in Maurer's clefts.
- Examined Plasmodium falciparum-infected erythrocytes to detect the antigen's presence in blood stages.
- Analyzed hepatic stages of Plasmodium falciparum for the expression of the common epitope.
- Assessed cross-reactivity with antigens on primate leukocytes and platelets.
Main Results:
- Confirmed the expression of an epitope common to the blood-stage antigen in the hepatic stages of Plasmodium falciparum.
- Demonstrated cross-reactivity of this epitope with antigens present on primate leukocytes and platelets.
- Identified a potential link between this shared epitope and autoantibody formation in malaria.
Conclusions:
- The study reveals a shared epitope between Plasmodium falciparum Maurer's clefts and primate leukocytes/platelets.
- This cross-reactivity offers a plausible explanation for the autoantibodies frequently observed in malaria patients.
- Understanding this molecular mimicry could inform strategies for managing malaria-associated autoimmune complications.