Abstracts (complete list) - Wissenschaft Online

Cédric VONARBOURG, Andreas DIEFENBACH
NK CELLS EXPRESSING CLASS II MHC MOLECULES: SEPARATE
LINEAGE OR JUST NK CELLS ?
NKG2D is a stimulatory immunoreceptor constitutively expressed by all NK cells, a
subset of NKT cells and the gd T cells of the skin. NKG2D interacts with a group of class
I MHC-like molecules (NKG2D ligands, NKG2DL) that are upregulated on stressed cells
whereas normal cells do not express these molecules. The NKG2D receptor/ligand
system functions as a sentinel system to alert the immune system to endogenous
cellular stress. Recent data from our lab indicated that vaccination of mice with NKG2DL
+ tumor cells (but not with the parental NKG2DL- cells) leads to enhanced priming of
tumor antigen-specific CD8 T cell responses. We wanted to investigate the molecular
mechanism of how NKG2D-mediated innate immune activation leads to the
enhancement of adaptive immunity. We hypothesized that NKG2D could regulate the
function of antigen presenting cells (APC). During these studies, we identified a
population of NKG2D+ cells co-expressing class II MHC which resides in the lymph
nodes (ca. 30-40% of all NK cells) whereas this population was rather small in the
spleen (