Abstracts (complete list) - Wissenschaft Online

Besir Okur, Rainer Glauben, Arvind Batra, Thorsten Stroh, Inka Fedke, Jeannette
Pietsch, Martin Zeitz, Britta Siegmund
Effects of Leptin on T helper cell polarisation
Leptin is an adipokine, initially described as regulator of food intake. Recent data
suggest an additional regulatory function in the immune system, for instance
stimulation of naïve T cells in the presence of leptin enhances polarisation to a Th1
phenotype. Aim of the present study was to characterize the effect of leptin on T cell
polarisation applying antigen-specific and unspecific systems. Naive CD4 + T cells from
Balb/c, leptin-deficient ob/ob and ovalbumine-TCR transgenic DO11.10 mice were
stimulated in vitro under polarising conditions either specifically in the presence of
antigen presenting cells (APC) and the specific antigen or unspecifically via anti-CD3
anti-CD28. As described previously stimulation of naive T-cells under non-polarising
conditions in the presence of leptin did increase the amount of Th1 cells. Furthermore,
under polarizing conditions in the antigen-unspecific system leptin not only increased
the polarization of Th1 cells, but furthermore induced a significant decrease of the
amount of Th2 cells. However, when applying the antigen-specific system under
polarising conditions, effects of leptin were more diverse and varied depending on the
antigen and APC chosen: In vitro stimulation of naive DO11.10 T-cells in the presence
of leptin did not affect the amount of Th1 cells and restimulation even decreased the
percentage of Th1 polarised cells. This effect was equally evident using WT or ob/ob
APCs. Similarly, polarisation to Th2 cells was not affected by leptin and restimulation in
the presence of WT APCs with ovalbumine resulted in increased, but restimulation with
OVA-peptide led to decreased Th2 polarization. In summary, our data further provide
strong evidence that the adipokine leptin does affect T helper cell polarisation. However,
this effect strongly depends on the type of antigen chosen, suggesting that in vivo leptin
effects might be far more intricately balanced than prior reports based on unspecific
studies in vivo may have suggested.