Mechanisms of Immunologic Injury of Rat Peritoneal Mast Cells

Summary Rabbits injected with concentrated rat peritoneal mast cells emulsified with Freund’s adjuvant produced an antiserum, Ra anti-RMC, capable of sensitizing peritoneal mast cells for histamine release by complement in normal serum. An absolute requirement for second component and sixth component of complement was established by demonstrating that serum genetically deficient in these components failed to produce histamine release unless reconstituted with the respective purified component. The cytotoxic nature of the reaction was indicated by the association of histamine release with the uptake of vital dye. The specificity of Ra anti-RMC for mast cells was indicated by: the ability of the antiserum to sensitize concentrated mast cells (90% purity) for complement-dependent histamine release, the removal of sensitizing activity by absorbing the antiserum with concentrated mast cells, and the immunofluorescent demonstration that the antiserum interacts with antigen(s) on the surface of the mast cell. The capacity of Ra anti-RMC to sensitize rat mast cells for cytotoxic histamine release was demonstrated in vivo in skin and peritoneal cavity.