Classical and alloimmune anaphylactic degranulation of isolated single mast cells.

Viable mast cells, directly isolated by micromanipulation from a mouse peritoneal cell suspension, were deposited on the bottom of microtiter-plate wells and submitted to histamine release. Conventional antigen-induced anaphylactic degranulation as well as direct allogeneic anaphylactic degranulation were strongly inhibited when these mast cells were settled on normal tissue culture plastic surfaces. Nevertheless, normal degranulation could be recovered by pretreatment of the experimental surface with a multipositive charged molecule (poly-L-lysine). Under these conditions, we demonstrate that the degranulation of one isolated mast cell is possible and consequently, as regards the direct allogeneic anaphylactic degranulation, confirm the "self-triggering mechanism" in which the recognition of histocompatibility antigens on the membrane of the mast cell itself is the trigger to the secretory response. The technique of monocellular degranulation described in this paper provides a new tool which leads us to think that the problem of detection of anaphylactic antibody-secreting cells can be solved.