Induction of a passive cutaneous anaphylaxis inhibitory factor in mice.

The administration of a purified protein from Dactylis glomerata pollen, named Dactylis inhibitory protein (DIP), to Balb/C mice results in the production of a heat-resistant seric factor that blocks the passive cutaneous anaphylaxis (PCA) reaction in rat skin. This PCA inhibitory factor (PCA-IF) was purified following different purification procedures and analyzed in sodium dodecyl sulfate polyacrylamide gel. Amongst the array of bands detected it was possible to ascribe the inhibitory activity to a protein band of 76,000 daltons but only when it was associated either with another protein band of 69,000 daltons (obtained after a one-step purification procedure) or two other protein bands of 55,000 and 26,000 daltons (obtained after a three-step purification procedure). The inhibitory activity of the PCA-IF is present at a low level in normal Balb/C mice sera and is enhanced after DIP treatment of the mice.