CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Changes in cells subsets present in the thymus after systemic Th1 inflammatory/infectious processes.
Autor/es:
NATALIA BAEZ; FABIO CERBAN; RODRIGUEZ GALÁN MARIA CECILIA
Lugar:
Los Cocos-Córdoba
Reunión:
Congreso; LXI Reunión Científica Anual de la Sociedad Argentina de Inmunología.; 2013
Institución organizadora:
Sociedad Argentina de Inmunología
Resumen:
We have demonstrated that during systemic
inflammatory/infectious processes, peripheral mature T cells are able to enter
the thymus. These cells could be distinguished from resident thymocytes based
on the expression of high levels of the surface marker CD44. In this work we
further characterized peripheral T cells residing in the thymus but also evaluated
maturation changes that experience resident thymocytes during
inflammatory/infectious Th1 processes. We found that resident SP (simple
positive) thymocytes (CD44lo) are able to sense systemic
inflammatory stimuli by changing its phenotype similar to mature T cells in
secondary lymphoid organs (SLO). T cells found in SLO express high levels of Qa2
and low levels of CD24. In contrast, immature SP thymocytes expressed the
opposite phenotype (Qa2lo-CD24hi). The inversion in the
expression of these markers is expected to happen when recent thymic emigrants
contact SLO, however, we observe that under certain Th1 systemic situations
(LPS or IL-12+IL-18 in vivo or C. albicans and T. cruzi infections) SP thymocytes adopt the mature phenotype
similar to a peripheral T cell (Qa2hi-CD24lo) (p<0.05,
n=10-15). Regarding peripheral T cells
that invade the thymus under these circumstances, we observed that they reside
mainly in the thymic medulla (by IF staining) and that CD8+ CD44hi
T cells expressed the transcription factor EOMES, characteristic of ?innate CD8
T cells? (p<0.05, n=8). Moreover, migration of the innate CD8+ T
cells is an Ag-independent process probably driven by inflammatory mediators since
CD8+ CD44hi EOMES+ T cells from OT-1 mice
infected with T. cruzi (OVA is not
expressed by the parasite) can also be found in the thymus between 10-14 days
post-infection (p<0.05, n=5). All together, we conclude that the thymus is a
target organ during systemic inflammatory/infectious processes being
infiltrated by mature peripheral innate CD8+ T cells and altering
the normal maturation of immature resident thymocytes