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| Author(s): |
Nágela Ghabdan Zanluqui
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2021-10-13 |
| Examining board members: |
Jean Pierre Schatzmann Peron;
Fernando de Queiroz Cunha;
Jorge Elias Kalil Filho;
Pryscilla Fanini Wowk
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| Advisor: | Jean Pierre Schatzmann Peron |
| Abstract | |
Flavivirus infections are a cause of great concern around the world due to recurrent epidemics and high mortality rates, being a major public health problem. The relevance of the study of ZIKV infection was highlighted due to the huge number of babies born with microcephaly, especially in Northeast Brazil, and in May 2016 our group proved the causal relationship between ZIKV infection during pregnancy and cases of microcephaly. Knowing that ZIKV, as other flaviviruses, has the ability to modulate the host\'s innate and adaptive immune response, this project aimed to understand the role of neutrophils, and CD8+Foxp3+ T cells, in the control of viral replication and in disease progression in a murine ZIKV infection model. For this, peripheral blood neutrophils from healthy individuals and bone marrow neutrophils from C57BL/6 and SJL animals were used for in vitro experiments, and for in vivo experiments, C57BL/6 IFNAR-/-, C57BL/6 WT, C57BL/6 Foxp3GFP and C57BL/6 CD8-/- mice were infected with ZIKV, followed by the most varied analyzes for viral quantification, gene expression and cell populations of interest. Our results showed that ZIKV was able to infect murine and human neutrophils in vitro without interfering with the half-life, ROS production and NET release of these cells, in addition to not inducing expression of cell activation markers such as MHC-I, MHC-II, CD80, CD86 and IFNAR. Regarding gene expression, only Ifn-b, Axl, Nos2 and Tnf were altered. Additionally, ZIKV-infected neutrophils were detected in blood and placenta from infected mice, and the transfer of in vitro ZIKV-infected neutrophils to pregnant mice was capable to cause systemic infection, in addition to the transfer of viral particles to fetuses, proving that neutrophils can act as a Trojan horse for viral replication and dissemination in ZIKV infection. On the other hand, the infection of mice deficient in CD8+ cells presented an oscillatory profile, with higher viral copies in the serum, while a lower number of viral particles in the spleen compared to the control group. Furthermore, PCRArray analysis showed alterations in the expression of genes related to viral recognition, such as Tlr3 and Nod2 and host immune response Nfkb1, FasL and Ifn-a. The analysis of spleen cell populations showed that ZIKV infection induces an increase in the population of CD8+Foxp3+ T cells, the CD8+regulators. However, these cells induced during ZIKV infection express high levels of FasL and Ly6C and seems to be not responder to ZIKV infection, whereas CD8+Foxp3+ T cells from naïve mice induce greater viral replication in adoptive transfer experiment. Such findings lead us to believe that there is an attempt by the pathogen to modulate the innate and adaptive immune response, in order to facilitate its replication and permanence in the host. In summary, this work sought to elucidate the immunobiology of ZIKV infection during pregnancy, and to correlate it with the susceptibility to Congenital Syndrome Caused by the virus (AU) | |
| FAPESP's process: | 16/07371-2 - Characterization of the role of T CD8+ lymphocytes in Zika virus infection |
| Grantee: | Nagela Ghabdan Zanluqui |
| Support Opportunities: | Scholarships in Brazil - Doctorate |