|Reference : . Do innervation of germinal centre and contacts between FDC and nerve fibers be keys...|
|Scientific congresses and symposiums : Poster|
|Life sciences : Anatomy (cytology, histology, embryology...) & physiology|
|. Do innervation of germinal centre and contacts between FDC and nerve fibers be keys to understand the susceptibility difference between bovines and humans to the BSE agent?|
|Defaweux, Valérie [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Histologie humaine >]|
|Dorban, G. [ > > ]|
|Antoine, Nadine [Université de Liège - ULg > Département de morphologie et pathologie > Histologie >]|
|Heinen, Ernst [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Histologie humaine >]|
|poster et abstract book|
|[en] Background: In regard to BSE and vCJD, the agent tropism for lymphoid tissues is completely different even if the infectious strain responsible and the way of inoculation are identical. During vCJD, the infectious agent crosses the digestive barrier and multiplies in lymphoid organs, before progressively reaching the brain. Indeed, in vCJD, it accumulates in the ileum, tonsils, spleen and appendix of infected individuals. In contrast, in cattle, the BSE agent has a low affinity for lymphoid tissues and mainly accumulates in the nervous system. During preclinical stages, infectivity, other than that in the peripheral nervous system or central nervous system, is confined in the distal ileum of orally infected cattle. So, it appears that, at least in the case of BSE and vCJD, host properties can influence the accumulation of the infectious agent in lymphoid organs.
Objectives and methods: In this study, we analysed by confocale microscopy the mucosal innervation and the interface between nerve fibres and FDC in bovine and human tonsils using a panel of antibodies. Since differences in the innervation of lymphoid organs depending on species and on age have been reported, we analysed two categories of bovines (calves less than 12 months old and bovines older than 24 months) and two categories of humans (patients less than 5 years old and patients older than 25 years).
Results: In both species, ways of innervation by-passing germinal centres could be postulated: nerve fibres are widely distributed in antigen/cell traffic area: the lamina propria, the interfollicular zone and the lymphoepithelial area. We pointed out that, only in tonsils of bovines older than 24 months, nerve fibres are observed to be in contact with FDC. In contrast, in human tonsils, no nerve fibres established contacts with FDC, whatever the age.
Discussion: Innervation of germinal centres can be said to be an age-dependent dynamic process in bovines. The weak innervation of the secondary lymphoid organs could thus be a rate-limiting step to neuroinvasion in humans. This species difference could influence the way of neuroinvasion and thus, the susceptibility of bovines and humans to the BSE agent.
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