Change in sensitivity to lysophosphatidylserine of mouse bone marrow-derived mast cells during cultivation with fibroblasts.

Lysophosphatidylserine (lysoPS) is known to enhance IgE-mediated activation of rodent connective tissue mast cells (CTMCs). In the present study, we investigated the effect of lysoPS on degranulation of interleukin-3-dependent mouse bone marrow-derived mucosal mast cells (BMMCs) and of their CTMC-like differentiated cells. In the absence of lysoPS, BMMCs released approximately 20% of their histamine when sensitized with anti-dinitrophenyl (DNP) IgE and challenged with DNP-conjugated antigen. When stimulated in the presence of lysoPS, no appreciable enhancement was observed. On the other hand, histamine release from BMMCs, which had differentiated to CTMC-like cells by co-culture with 3T3 fibroblasts, was enhanced 2- to 3-fold by the addition of lysoPS. The maximum potentiation was observed at 5 x 10(-6) M lysoPS. These results suggest that mast cells might acquire their dependence on exogenous lysoPS during differentiation from mucosal mast cells to CTMC-like cells.