[01] Munsoor Mohammed Munsoor, College of Medical Laboratory Science, Sudan University of Science and Technology, Khartoum, Sudan. [02] Khalda Mirghani Hamza, College of Medical Laboratory Science, Sudan University of Science and Technology, Khartoum, Sudan. [03] Abeer Eltuhami, Institute of Endemic Diseases, Faculty of Medicine, University of Khartoum, Khartoum, Sudan. [04] Ibrahim M. El-Hassan, Institute of Endemic Diseases, Faculty of Medicine, University of Khartoum, Khartoum, Sudan.

Introduction: Antigen-specific antibody-mediated immune responses play an important role in natural protection against clinical malaria, but conflicting estimates of this association have emerged from immuno-epidemiological studies in different geographical settings. This study was aimed at assessing in a standardized manner the relationship between the antibody responses to the most promising malaria vaccine candidate antigens, glutamate rich protein (GLURP) and protection from clinical malaria, in a cohort of Gazira inhabitants, central Sudan. Methods: Standardized ELISA protocols were used to measure IgG and IgG subclass levels to GLURP antigen in plasma samples from 133 central Sudan inhabitant aged 1to 80 years in a hospital based cross-sectional study. The levels of antibodies were related to the severity of malaria as indicated by anemia and parasitemia. The ELISA protocol follows AIA criteria to permit comparisons of results with those achieved in nearby African continents. Results: In the patients with parasitemia <5000 parasite/µl and normal hemoglobin, the results indicate high titres of the above antibodies to the three fragments of GLURP (RO, R1 and R2), although R2 and R0 encountered with significantly higher concentrations of the antibodies compared to patients with high parasitemia and anemia. The results also showed that IgG3 was presented with high concentration followed by IgG1 suggesting their protective role and their major participation in acquisition of immunity to malaria. The results also re-enforce the on going announcement that any future malaria vaccine should include GLURP fragments notably GLURP-R2 and GLURP-R0. Conclusion: The present study provided and presented here the first evaluation of humoral responses to recombinant GLURP in individuals living in Central Part of Sudan. This work also showed the gradual acquisition of immunity to malaria among individuals living in Gazira State in central Sudan. Finally, the study has confirmed the importance of antibodies to GLURP in reducing the risk of clinical malaria in Central Sudan, thus substantiating its potential as a malaria vaccine candidate.

Malaria Immunity, Plasmodium Falciparum GLURP, Malaria in Central Sudan

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