Assessment of the humoral immune response against Plasmodium vivax antigens in patients with malaria relapses.

• Grant number: 24/05218-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2024
• End date: April 30, 2025
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: Fabio Trindade Maranhão Costa
• Grantee: Mariana Ribeiro Gonçalves
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 17/18611-7 - Development of new tools for search and validation of molecular targets for therapy against Plasmodium vivax, AP.TEM

Abstract

Plasmodium vivax is the most prevalent species that causes human malaria outside Africa and its biology poses a challenge to eradicating the disease. The characteristics of this species include the ability to cause recurrences, which correspond to the reappearance of clinical signs and peripheral parasitemia weeks to months after diagnosis and treatment of the initial infection. To theRecurrences can have several causes, among which the reactivation of latent hepatic forms of the parasite, the hypnozoites, stands out, which is called relapse. In the context of controlling and eliminating the disease, the identification of individuals carrying hypnozoites, which occurs silently and undetectably by conventional diagnostic methods, is crucial in controlling this disease. In this way, we intend to characterize the dynamics of the antibody response against P. vivax blood antigens inindividuals with vivax malaria admitted to the Fundação de Medicina Tropical (Manaus-AM) who presented, or did not, recurrences of malaria over a period of90-day follow-up. The antibody response against P. vivax blood antigens(AMA-1, MSP1-19 and CSP vk210) will be determined by conventional ELISA serology in plasma samples collected throughout follow-up and correlated with clinical, demographic, epidemiological and parasitological data of patients admitted to the cohort, including parasite biomass through quantification. of pLDH. To date, approximately 250 patients have been recruited, with a frequency of recurrences of 19.7% that occurred between 31-90 days after admission to the study. However, as a genuinely true reference for relapses, we will also analyze samples of individuals who presented recurrences outside the malaria endemic area admitted to FIOCRUZ-RJ. The results obtained in this study will be useful to identify a signature of biomarkers capable of detecting individuals at high risk of experiencing relapse episodes, which can be used in epidemiological surveillance and as a guiding tool for intervention.