Antibodies to Specific Domains of Erythrocyte Membrane Protein-1 and Its Relationship with Protection from Severe Malarial Anemia: A Prospective Study Among Ghanaian Children
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Background: erythrocyte membrane protein-1 (EMP-1) is important in malaria pathogenicity as it mediates -infected erythrocytes cytoadherence to host endothelial microvasculature receptors. Naturally acquired antibodies against specific EMP-1 antigens may be beneficial in clinical malaria protection. This study determined antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of EMP-1 in children with malaria in Tamale, Ghana.
Methods: Sixty -infected children, and 30 controls, aged 1-12 years were recruited for this case-control study from April to July 2023 in Northern Ghana. Participants with uncomplicated malaria had asexual in peripheral blood and Hb ≥ 5.0 g/dL, and severe malaria was diagnosed when participants had Hb < 5.0 g/dL in addition to asexual in peripheral blood. Blood cell indices were measured using hematology analyzer, and IgG antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of EMP-1 and pro-inflammatory cytokines were detected using enzyme-linked immunosorbent assay. Data were analyzed using SPSS version 26.0.
Results: The prevalence of EMP-1 IgG antibodies among -infected children and the uninfected group was 65.0% and 6.7%, respectively. EMP-1 IgG antibodies were present in 83.3% of uncomplicated malaria cases, and 46.7% in severe malaria subjects. Plasma levels of EMP-1 IgG antibodies were elevated in participants with uncomplicated malaria compared to those with severe malaria ( < 0.001). Hemoglobin, RBC, HCT, and platelet were significantly lower among -infected children without EMP-1 IgG antibodies than among those with the antibodies. Prevalence of anemia among children with EMP-1 IgG antibodies and those without the antibodies were 74.4% and 100%, respectively.
Conclusion: The high prevalence of EMP-1 IgG antibodies to DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains observed in participants with uncomplicated malaria, and the relationship between EMP-1 IgG antibodies and blood cell parameters could indicate that the antibodies may be related to effective erythropoietic response in malaria. Immune antibodies against DBLα2, CIDRα1, DBLβ12, and DBLγ6 domains of EMP-1 may suppress the deteriorating effects of EMP-1 antigens and provide immune protection against severe malarial anemia in children.