Abstracts (complete list) - Wissenschaft Online

ERIETTA STELEKATI, ZANE ORINSKA, ANNALENA BOLLINGER, SILVIA BULFONE-PAUS
Mast cells modulate CD8+ T cell responses.
Mast cells are considered to contribute dominantly to the establishment of an innate
immune response. However, mast cells can also act as important participants of the
adaptive immune response, by regulating the phenotype and function of the adaptive
immunity players (B cells, dendritic cells and T cells). T cells represent a cutting edge
for the induction of adaptive immunity and CD8+ T cells have been reported to be
recruited in vivo by mast cells. Therefore, this study was focused on the crosstalk
between mast cells and CD8+ T cells. The potential of mast cells to induce antigenspecific
CD8+ immune responses was investigated. We could demonstrate that bone
marrow derived mouse mast cells (BMMCs) labelled with OVA-derived OT-I peptide were
able to induce activation, cytokine production and proliferation of transgenic, OT-I
specific CD8+ T cells. Moreover, blocking of cytokine synthesis in BMMCs by mitomycin
C treatment and, to a higher extent, fixation of BMMCs by paraformaldeyde treatment,
decreased their ability to specifically activate CD8+ T cells, thus demonstrating that the
specific activation of CD8+ by BMMCs is dependent both on membrane-bound peptides
and on soluble factors produced by BMMCs. Furthermore, Toll like receptor – specific
pre-priming of BMMCs increased their ability to induce antigen specific CD8+ responses.
Finally, BMMCs were able to induce antigen specific proliferation of naïve primary CD8+
T cells in vivo, as measured by CFSE staining. Taken together, these data demonstrate
that mast cells can potently induce antigen specific CD8+ responses. This function of
mast cells can be modulated by Toll like receptor signals. Thus, it is suggested that
mast cells play a key regulatory role at the cross-roads of innate and adaptive immunity.