Inhibition of anaphylactic histamine release and pulmonary distress in rats by nonspecific IgE

Myeloma IgE, obtained from ascitic fluid of rats previously inoculated with the IgE-producing cell line IR-162, was administered in prophylactic and therapeutic regimens to rats passively and actively sensitized to ovalbumin. Administration of myeloma IgE prior to passive sensitization resulted in approximately 95% inhibition of anaphylactic histamine release and significant protection from anaphylactic pulmonary distress. Myeloma IgE treatment prior and subsequent to active sensitization brought about a 70-80% inhibition of anaphylactic histamine release. A similar pattern of protection was seen in animals that received 5 but not 3 weekly myeloma IgE treatments subsequent to active sensitization. These findings indicate that treatment with nonspecific IgE prior to sensitization is effective in blocking anaphylactic reactions but competition with cell-bound IgE in sensitized animals requires prolonged administration of relatively large quantities of 'nonsense' IgE.