Intracameral injection of antigen potentiates the production of antigen-specific T cell proteins in serum after the induction of delayed-type hypersensitivity.

PURPOSE To determine whether the introduction of antigen into the anterior chamber induces the production of extracellular antigen-specific T cell proteins (T cell antigen-binding molecules [TABM] specific for the antigen. METHODS Balb/c mice received an intracameral or subconjunctival injection of trinitrophenylated spleen cells (TNP spleen cells) before skin sensitization and challenge with picrychloride. The production of TNP-specific TABM in serum was quantified by enzyme-linked immunosorbent assay-based antigen binding and immunoblotting using a rabbit antiserum raised against a monoclonal antigen-specific T cell protein that induces suppressor T cells. RESULTS Intracameral, but not subconjunctival, injection of TNP spleen cells before contact sensitization increased the level of TNP-specific TABM in serum. At 2 days, TABM levels began to rise and peaked at 5 days after contact sensitization. Anterior chamber injection of TNP spleen cells alone into nonimmunized mice did not induce a detectable increase of TNP-specific TABM in serum. Mice that did not receive an intracameral TNP spleen cell injection but were made contact sensitive to TNP showed a diminished TNP-specific TABM response. Specificity of the TABM induced by intracameral-injection and sensitization for the TNP hapten was documented by showing that the induced TABM binds TNP-bovine serum antigen (BSA) but does not bind either BSA alone or azobenzenearsonate-ovalbumin and that immune sera raised against ovalbumin did not contain an increase in TNP-specific TABM. TNP-specific TABM in the sera of mice receiving an intracameral injection of TNP spleen cells, followed by contact sensitization with picrylchloride (PCl), were purified by affinity for TNP and were resolved by polyacrylamide gel electrophoresis and immunoblotting as M(r) 110,000 polypeptides. CONCLUSIONS Serum levels of TNP-specific TABM induced by contact sensitization alone are enhanced fourfold to fivefold when sensitization is preceded by the intracameral, but not the subconjunctival, injection of TNP spleen cells. The authors propose that besides suppression of systemic delayed type hypersensitivity, the intracameral injection of antigen into nonimmune mice may prime an increased production of TABM, which may indicate systemic activation of the immunoregulatory T cell circuit.