immunology of infectious and parasitic diseases - XXXVII Congress ...

TRYPANOSOMA CRUZI PARASITE INDUCES RELEASE OF NEUTROPHIL
EXTRACELLULAR TRAPS (NETs).
Daniel Sousa-Rocha 1 ; Larissa Figueiredo Alves Diniz 1 ; Mariana Thomaz-
Tobias 1 ; Priscila Silva Sampaio Souza 1 ;Bruna Castilho Soto Campanha 1 ;
Phileno Pinge-Filho 2 ; Karina Alves Toledo 1
1 Faculdade de Ciências e Letras de Assis, UNESP - Univ Estadual Paulista;
2 Universidade Estadual de Londrina.
Introduction: Diseases triggered by protozoa consist of serious public health
problem, mainly due to high relative mortality associated with them. The
Chagas Disease, described for the first time by Carlos Chagas in 1909, which
the aetiological agent is the Trypanosoma cruzi, can develop fatal events as
inflammation of the myocardium, the meninges and brain regions. Currently,
control of replication of the parasite by drugs involves intense immune response
included innate immunity cells such as monocytes, eosinophils and neutrophils.
NETs (Neutrophil Extracellular Traps) have been described as a new
mechanism of the microbicide neutrophils to
quickly capture and kill many pathogens, including bacteria, fungi and parasites
as Toxoplasma gondii and Leishmania sp. Here, our aim was to investigate if
T.cruzi parasite and its soluble molecules are able to stimulate to form and
release NETs from human neutrophils. Methods: In order to answer our
questions, human neutrophils were isolated from blood by using sedimentation
gelatin method and co-cultivated with different number of parasites or different
doses of soluble extract from T.cruzi parasite. The end of incubation the cells
were (i) fixated and incubated with DAPI for analysis by fluorescence
microscopy or (ii) incubated with MTT salt.
Results: Images acquired and analyzed has been demonstrated that T.cruzi
and its soluble molecules induced NET release by human neutrophils in a
parasite number- and dose-dependent manner. This release was similar to
positive control (fMLP 10 -6 M) and opposite to negative control (RPMI only).
Interestingly, when the neutrophils were incubated with the parasite, we could
see small bright blue dots on the NETs. This effect did not observed when
neutrophils were incubated with soluble molecules from parasite. During coincubation,
cell viability was not affected since the MTT salt was equally
metabolized in all tested conditions. Conclusion: Together, our preliminary
results suggest that T.cruzi and its soluble molecules are able to induce the