Abstracts (complete list) - Wissenschaft Online

Stefan Welte, Kathrin Pietschmann, Lothar Marischen, Susann Beetz, Ina Martens,
Daniela Wesch, Dieter Kabelitz
Human γδ T lymphocytes express pattern recognition receptors
Pattern recognition receptors such as Toll-like (TLR) and NOD-like receptors recognize
conserved pathogen-associated molecular patterns which distinguish foreign/ dangerous
organisms from the host cells. With respect to human blood derived γδ T lymphocytes,
we found reproducible expression of TLR1, 2, 3, 5, 6, 7 and NOD2 mRNA. To analyze
the functional relevance of the expression of these proteins in more detail, we
stimulated freshly isolated, highly purified γδ T cells with TLR specific surrogate ligands,
e.g. bacterial lipopeptides Pam2CSK4 and Pam3CSK4 for TLR2, poly(I:C) for TLR3,
flagellin for TLR5, and with the NOD2 ligand MDP. In general, all used TLR ligands exert
no or only limited effects by itself but increased the T cell receptor (TCR) stimulated IFNγ
production of γδ T lymphocytes. Furthermore, incubation with TLR ligands enhanced
secretion of TNF-α, RANTES and MIP-1α. MDP caused a small increase in IFN-γ
production of TCR stimulated cells, also in combination with Pam2CSK4 and Pam3CSK4. Furthermore, we investigated freshly isolated Vδ1 and Vδ2 γδ T lymphocytes, the two
major subpopulations in the human blood, separately. Both cell populations express a
similar level of the pattern recognition receptors. In functional tests, Vδ1 γδ T cells
produce only little IFN-γ upon stimulation, whereas Vδ2 γδ T cells are strong IFN-γ
producers. The differential stimulation by the different TLR and NOD ligands is currently
under investigation.
This study was supported by DFG SPP 1110 “Innate Immunity” (Ka 502/8-3).