Phagocytic and tumor necrosis factor alpha response of human mast cells following exposure to Gram-negative and Gram-positive bacteria

Recent studies have implicated rodent mast cells in the innate immune respo nse to infectious bacteria. We report that cord blood-derived human mast ce lls (CBHMC) obtained from culture of cord blood progenitors phagocytozed an d killed various gram-negative and gram-positive bacteria and simultaneousl y released considerable amounts of tumor necrosis factor alpha. Overall, th e extent of the endocytic and exocytic response of CBHMC correlated with th e number of adherent bacteria. Thus, human mast cells are intrinsically cap able of mediating microbial recognition and of actively contributing to the host defense against bacteria.