Objectives and design: We investigated the effects of microbial components on the uptake of microbes by mast cells (MCs), and studied the change in cytokine production in MCs after bacterial uptake.
Material or subjects: LAD2 human mast cells, cord-blood and peripheral-blood derived MCs were employed to analyze their surface molecule expression and cytokine generation by flow cytometry. Bacterial internalization in these MCs was observed by confocal microscopy and flow cytometry.
Results: Complement receptor 3 expression was augmented by LTA but not by PGN or 3CpG-oligodeoxynucleotide. LTA also enhanced the uptake of opsonized bacteria (over twofold augmentation). After bacterial uptake, MCs augmented the production of chemoattractant cytokines for neutrophils, while Th1 and Th2 cytokine production showed little or no change.
Conclusions: LTA increases the capability of the MC as a sentinel in the host immune response, and some bacterial components direct human MC function towards innate immunity after pathogen infection.