Banca de DEFESA: RAFAEL TEIXEIRA TIBURCIO DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAFAEL TEIXEIRA TIBURCIO DOS SANTOS
DATA : 11/06/2019
HORA: 14:00
LOCAL: Auditótio Aluízio Prata - Instituto Gonçalo Moniz/FIOCRUZ
TÍTULO:

EVALUATION OF the ROLE OF HUMAN NEUTROPHILS IN CONTROLLING INFECTION by L. AMAZONENSIS IN DENDRITIC CELLS

PALAVRAS-CHAVES:

neutrophils, dendritic cells, Leishmania, DC-SIGN, lipid mediators

PÁGINAS: 74
GRANDE ÁREA: Ciências Biológicas
ÁREA: Imunologia
RESUMO:

Introduction: Leishmaniasis is a collection of neglected diseases that afflict millions of people on a global scale. This pathology is caused by protozoa belonging to the genus Leishmania whose transmission vectors are phlebotominal arthropods that harbor the parasite. The infection begins during the blood meal of sand flies, when the promastigote forms of the parasite and immunomodulatory salivary components in the skin of the mammalian host occurs. Several types of immune cells participate synergistically in the response against Leishmania. Among these cells, neutrophils, polymorphonuclear cells that play a key role in the recruitment and activation of other immune cells, stand out. Neutrophils are able to establish an intimate dialogue with dendritic cells through membrane receptors such as DC-SIGN, thus promoting the establishment of integrated immune responses in the control of infection. However, little is known about the role of activated neutrophils in the outcome of Leishmania amazonensis infection in human dendritic cells. Objective: The present study sought to investigate the relevance of the interaction between activated neutrophils and infected dendritic cells in the course of in vitro infection by L. amazonensis. Material and methods: Neutrophils and human dendritic cells were purified from peripheral blood from healthy donors. Neutrophils were activated with fibronectin for 1 hour and subsequently incubated with dendritic cells infected by L. amazonensis. Results: Our results indicate the participation of neutrophils in infection control independently of their activation state. Neutralization of enzymes present in the neutrophil granules pointed out that elimination of the parasite occurs independently of such enzymes. We found that the destruction of Leishmania was dependent on direct contact via DC-SIGN between neutrophils and dendritic cells. We note that the production of lipid mediators and maturation of dendritic cells also occurred in a manner dependent on this receptor. Finally, we observed that parasite destruction needed the participation of TNFα and LTB4 produced in the co-culture. Conclusion: Our results have shown that human neutrophils modulate both the maturation and the ability of infected dendritic cells to destroy the parasite in a manner dependent on direct physical contact through DC-SIGN and the subsequent production of TNFα and lipid mediators.

MEMBROS DA BANCA:
Interno - 024.952.207-11 - CAMILA INDIANI DE OLIVEIRA - USP
Presidente - 233.804.895-49 - CLAUDIA IDA BRODSKYN - UFBA
Interno - 2516360 - DEBORACI BRITO PRATES
Externo à Instituição - MARIA OLIVIA AMADO RAMOS BACELLAR - UFBA