Effect of N-(2-carboxyphenyl)-4-chloroanthranilic acid disodium salt (CCA) on the induction of helper and suppressor T cells in vitro and in vivo.

Keyhole lympet hemocyanin (KLH)-specific suppressor T (Ts) cells that suppress the in vitro secondary anti-trinitrophenyl (TNP) PFC response to TNP-KLH could be induced when murine spleen cells were precultured with KLH. N-(2-carboxyphenyl)-4-chloroanthranilic acid disodium salt (CCA) at 1-100 micrograms/ml augmented the in vitro induction of Ts cells when the cells were precultured with a suboptimal dose of KLH (10 micrograms/ml). Ts cell-induction was, however, rather slightly inhibited by the same concentrations of CCA when the lymphocytes were precultured with an optimal amount of KLH (100 micrograms/ml). In the in vivo experiments, the daily administration of 10 mg/kg CCA for 4 weeks augmented or inhibited Ts cell-induction when mice were immunized with a suboptimal (30 micrograms/body) or an optimal (100 micrograms/body) amount of KLH, respectively. However, CCA had no effect on the induction of Ts cells by concanavalin A in vivo. On the other hand, CCA augmented the induction of helper T (Th) cells both in vitro and in vivo when Th cells were induced with a suboptimal amount of antigens. In contrast, the augmentative effect was no longer observed when Th cells were induced by an optimal amount of antigens. These results suggest that CCA is a compound showing immunomodulating properties that affect Ts and Th cell-induction depending on immunological conditions. These immunopharmacological profiles are discussed in connection with its clinical application to an autoimmune disease like rheumatoid arthritis.