Background: The function of dendritic cells (DC), the most important cell population for the induction of specific immune responses, is often altered in cancer patients. Since mistletoe extracts are applied to tumour patients, their influence on the activation/generation of DC was investigated.
Materials and methods: Monocytes from healthy individuals were stimulated with the mistletoe extract (HM) or the mistletoe lectin 3 (ML-3) in the presence or absence of GM-CSF/IL-4.
Results: HM slightly but significantly stimulated the expression of CD83 but not CD1a in the presence of GM-CSF/IL-4, while in their absence only CD86 was activated. In pre-generated immature DC, HM and ML-3 enhanced the expression of CD86 but did not significantly activate CD83/CD1a. There was no relevant influence on the expression of HLA-class-I or class-II molecules.
Conclusion: For the first time, our data demonstrate an influence of a mistletoe extract on the activation/generation of DC, but it remains to be elucidated whether the function of DC is also activated and especially whether this rather slight effect is of importance for tumour patients.