Abstracts (complete list) - Wissenschaft Online

Stephan Schlickeiser, Katharina Tschimmel, Andreas Meisel, Christian Meisel, Inga
Gebuhr, Uwe Pleyer, Hans-Dieter Volk, Birgit Sawitzki
TARGETING N-GLYCOSYLATION AFFECTS APC FUNCTION IN
VITRO AND IN VIVO
Introduction: Transfer of tolerogenic DCs has become an attractive treatment
alternative in transplantation and autoimmunity. Although distinct glycosylation patterns
on tolerogenic immature DCs have been described, the impact of post-translational
protein modification on DC function is still unexplored. Here we analyzed the effect of
hypo-N-glycosylation on DC maturation and allo-stimulatory capacity in vitro and in
vivo.
Methods: BALB/c bone marrow-derived DCs were treated with the specific alpha-1,2mannosidase
inhibitor kifunensine. After 24 h, DCs were matured with LPS, TNFa or anti-
CD40mAb. DC N-glycosylation state (PHA binding), expression of MHCII and CD86 were
analyzed by flow cytometry. Allo-stimulatory capacity of DCs was determined by
analyzing the proliferation of co-cultured allogeneic T cells from naïve C57BL/6 mice.
Capacity of hypo-N-glycosylated endogenous APC to elicit an effective anti-bacterial
response was tested by injecting kifunensine in a mouse model of stroke (MCAO).
Results: We detected a significantly enhanced PHA binding capacity in response to
maturation stimuli. Hypo-N-glycosylation was accompanied by diminished surface
expression of MHCII and CD86 prior and after maturation. LPS-induced activation of
hypo-N-glycosylated DCs dramatically diminished their allo-stimulatory capacity as
proliferation of co-cultured allogeneic T cells was completely abrogated. Control animals
subjected to MCAO developed spontaneous systemic bacterial infections due to stroke
induced immunodepression. Interestingly, injection of kifunensine dramatically
enhanced APC deactivation, increased bacteremia and reduced overall survival rate
from 75 to 37.5 %. In contrast Sham operated mice receiving kifunensine were not
affected.
Conclusions: Our results indicate that, depending on their maturation state, differences
in protein N-glycosylation levels condition DCs to either stimulate or deactivate T cells.
Thus, interference with APC N-glycosylation has high potential for tolerance induction in
transplantation and autoimmune models.