Avaliação da capacidade de extratos proteicos de Plasmodium falciparum em estimular a produção de anticorpos específicos e induzir hemólise de eritrócitos humanos não infectados na presença do sistema complemento

Abstract

Malaria is a parasitic infectious disease, caused by protozoa of the genus Plasmodium and characterized by acute fever, chills, sweating and headache. six species cause human malaria in the world: P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi and P. simium. Most cases of severe human malaria are attributed to infections by Plasmodium falciparum, considered the most aggressive due to tissue hypoxia resulting from several factors, including severe anemia. According to the 2017 World Malaria Report, there were about 219 million cases of malaria and 435.000 deaths from the disease each year. As an intracellular parasite, Plasmodium depends on the host to survive and genetically determined factors can influence the individual's susceptibility to clinically developing malaria, especially those that result in hematological changes. Thus, the present study aims to evaluate the participation of the complement system in the genesis of the phenomenon of hemolysis induced by Plasmodium falciparum in in vitro models and, in the second moment, to develop and standardize in vitro methodologies for understanding the mechanism of hemolysis of treated human erythrocytes with total P. falciparum proteins mediated by the complement system. For this, the methodology includes the in vitro cultivation of the W2 strain of Plasmodium falciparum, in addition to animal experimentation using Swiss mice immunized with protein extract from the culture of P. falciparum for the production of polyclonal serum, in addition to autologous hemolytic assays and determination of fragments complement by flow cytometry. The protein profiles visualized through polyacrylamide gel electrophoresis (SDS-PAGE), allows the identification of soluble P. falciparum proteins. The immunization of animals with processed extracts of P. falciparum enabled the production of functional murine anti-P falciparum antibodies that can even be used as a polyclonal serum.