Immunological unresponsiveness induced by non-phagocytosable immobilized hapten.

A study has been made of the effect of hapten attached to a non-phagocytosable carrier on the immune responses of guinea-pigs. Fragments of polyurethane sponge covalently linked with picryl groups were found to be non-immunogenic when introduced into the animals by a variety of routes. Animals implanted intraperitoneally with picrylated sponge fragments and subjected to a course of immunization with picryl chloride showed impaired immune responses to the hapten as measured by skin tests and antibody determinations. A critical factor determining whether unresponsiveness resulted was whether the fragment was wrapped in omentum. When the haptenated sponge remained outside the omentum both circulating antibody and delayed dermal reactivity were suppressed. When it was placed within the omentum the suppressive effect was seen on skin sensitivity but not on antibody production. This evidence together with information gathered on cellular infiltrates found in sponge sections suggest that hapten coupled sponge fragments induce immune unresponsiveness by selectively trapping white cells essential at the antigen-recognition stage of the immune response.