To show this, time of exposure to diesel exhaust was based on the developmental process of the thymus [ 33, 34].
More importantly, we demonstrate that PCV2 strongly impacts T-cell selection processes in the thymus.
CdxA and Nkx2 have been shown to be markers for endoderm germ layer patterning during gastrulation, a process necessary for formation of the thymus [ 54].
Collectively, they demonstrate that the principal genetic mechanisms currently known to regulate thymus organogenesis in the mouse are conserved in humans, and that key cellular processes, including the developmental origin of the thymus in the third pharyngeal pouches, are also conserved.
In lymph nodes (LN), which reflect the result of the differentiation process in the thymus, we observed a clear decrease in total cell numbers as well as in CD4, CD8, CD4 Treg and B-cell numbers (Table 1).
The DP cells may not participate in the anti-influenza immune response and their presence in the lung may simply be a consequence of an inflammatory process occurring in the vicinity of the thymus.
The widely held view is that these changes are caused by a combination of lifelong exposure to various pathogens and the gradual involution of the thymus, an irreversible process during which functional thymic tissue becomes progressively replaced by fat (Steinmann et al., 1985).
When T cells are being formed, they go through a culling process in the thymus, a gland near the heart.
Broadly, natural Treg arise during the normal process of maturation in the thymus, are selected on the basis of specificity for self antigens, express surface CD25 and Foxp3, and employ cell contact-dependent suppressive mechanisms.
Thin sections of the thymus tissue were obtained and placed on a glass and further processed for immuno-histochemistry.
