masterThesis
Perfil de memória e ativação de linfócitos T na leishmaniose visceral
Fecha
2010-12-03Registro en:
RODRIGUES NETO, João Firmino. Perfil de memória e ativação de linfócitos T na leishmaniose
visceral. 2010. 77 f. Dissertação (Mestrado em Bioquímica; Biologia Molecular) - Universidade Federal do Rio Grande do Norte, Natal, 2010.
Autor
Rodrigues Neto, João Firmino
Resumen
Visceral leishmaniasis (VL) in Brazil is a disease caused by Leishmania infantum
chagasi (L.i.chagasi). The clinical evolution post-infection depends on the
vertebrate host immune response, which is genetically mediated. This study
aimed to evaluate the immune response of individuals living in endemic area for
VL in the state of the Rio Grande do Norte, considering individuals with VL under
treatment (n = 9), recovered VL <1 year post treatment (n = 10), > 10 years posttreatment
(n = 9), uninfected individuals living in endemic areas (n = 7),
individuals that lost DTH response (n=6) and asymptomatic individuals for VL
(n=9). Peripheral blood cells were evaluated in the presence and absence of
soluble Leishmania antigens (SLA) and ex vivo, to determine activation,
presence of regulatory cells and memory cells. The Leishmania parasitemia and
anti-Leishmania antibodies were determined respectively by qPCR and ELISA.
Cells from individuals with VL under treatment showed less cell activation after
stimulation with SLA for the markers CD4/CD69, CD8/CD69 and CD8/CD25
compared with VL post treatment treatment (p <0.001). Apparently uninfected
individuals have a higher cell activation than symptomatic VL (p <0.001), with the
exception of CD8/CD25 marker (p = 0.6662). On the other hand, in the ex-vivo
group, significant differences were observed for CD4/CD69, CD8/CD69 and
CD8/CD25 between the 4 groups due to increased cell activation present in cells
of individuals symptomatic LV (p <0.001). VL cells under treatment, ex vivo, have
a lower percentage of memory cells (CD4/CD45RO and CD8/CD45RO) than
individuals VL post-treatment or control group (p = <0.01). Likewise, individuals
with symptomatic VL have fewer regulatory cells when stimulated by SLA
[CD4/CD25 (p = 0.0022) and CD4/FOXP3 (p = 0.0016)] and in the ex-vivo group
(p = 0.0017). Finally, DNA isolated from recovered VL contained Leishmania
DNA, supporting the hypothesis of non-sterile clinical cure for Leishmania
infection. Recovered VL, even 10 years after treatment have high levels of
memory cells, which may be due to the presence of stimulation, either by reexposure
to Leishmania or non-sterile cure