The immune response of rats injected in the footpads with protein antigens mixed with Bordetella pertussis organisms or with complete Freund's adjuvant has been investigated.
All the animals produced a high concentration of precipitating antibody in a short period of time. A different type of antibody, able to transfer passive cutaneous anaphylaxis and mast cell damage in normal rats, could also be demonstrated in many of the sera of these animals. This anaphylactic antibody appeared early during immunization, was present in low titers, and disappeared from the serum in about 4 weeks. The presence and titer of the anaphylactic antibody did not show any correlation with the concentration of total precipitating antibody.
The conditions for passive cutaneous anaphylaxis in rats, with rat anaphylactic antibody, were investigated. The optimal sensitization required a latent period of 16 hr and persisted at the skin site for many days.
The significance of these findings is discussed.