The Eosinophil Response to Toxoids and its Inhibition by Antitoxin

Intraperitoneal injections of specific toxoid induce a prolonged eosinophilia in the peritoneal exudate of BDF₁ mice previously immunized with tetanus toxoid combined with an adjuvant of pertussis vaccine. An injection of diphtheria toxoid into tetanus-primed mice induces a transient local eosinophilia which peaks at 24 hours. A challenging injection of tetanus toxoid produced a greater 24 hour eosinophil response and, in addition, a persisting accumulation of eosinophils peaking at 3 days and still evident at days 5 and 7. Injections of heterologous antitetanus globulins or isologous immune serum did not affect the transient eosinophilia, but did suppress the accumulation of eosinophils during the second or prolonged phase of the response to challenge.

Since humoral antibody prevented the antigen from inititating the eosinophil response in animals primed to respond to a challenging injection, it was concluded that antigen-antibody reactions per se could not be responsible for the prolonged phase of the eosinophil response. It was suggested that antibody may block the antigen from complexing with sensitized cells, thereby preventing the release of eosinophilotactic factors.