Abstracts (complete list) - Wissenschaft Online

Manuela Ahrendt, Reinhard Pabst, Ulrike Bode
Regeneration of transplanted lymph node fragments in the
mesentery to study effects of the gut lymph on lymph node
cytokines and chemokines
The mesenteric lymph nodes (mLN) are important for immune responses and
acquisition of oral tolerance. However, the influence of the gut in forming and regulating
the microenvironment of mLN and mediating immune responses is only partly known.
To study this, rat and mouse mLNs were removed and either fragments of mesenteric
(mLNtx) or peripheral lymph nodes (pLNtx) were transplanted into this region. Two, 4,
6, 8 and 10 weeks after transplantation the lymph node tissue was excised and different
cytokines and also chemokines were analysed by real-time PCR. The regeneration of the
transplants was documented by a re-established flow of lymph from the gut wall to the
lymph node tissue and by immunohistology of typical lymph node compartments.
IL-10 and CCL8 mRNA were expressed at a similar level to mLN in normal untreated
animals, whereas IL-4 regenerated completely after re-construction of the regenerated
lymph nodes. Interestingly, IL-2 was expressed in the pLNtx comparable to the pLN
control. In accordance with this expression pattern, CCR9 expression of the mLNtx was
similar to that of the mLN control, whereas in the pLNtx CCR9 expression was
comparable to that of the pLN control.
On the one hand mLNtx and pLNtx expressed cytokines, e.g. IL-4 and CCL8, in a similar
way after transplantation, suggesting that IL-4 and IL-10 were recruited from the
draining gut wall. On the other hand IL-2 and CCR9 mRNA were expressed comparable
to the control lymph nodes, indicating that these molecules were produced by the
surviving cells.
The regeneration of transplanted LN fragments in the mesentery is a useful technique to
define the role of the gut wall for protein levels of different cytokines and chemokines in
the mLN in inducing immune responses and oral tolerance in the gut immune system.