[Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanisms (II): Restorative effects on the suppression of antibody production].

The production of hemolytic plaque forming cells (HPFC) in the spleen of BALB/c mice immunized with sheep red blood cells was significantly inhibited by carrageenan treatment (0.3 mg/kg, i.p.; on days -3 and -1). Cysteine ethylester hydrochloride (ethylcysteine) restored the inhibition of the HPFC production by carrageenan treatment in a dose-dependent manner (10-100 mg/kg, p.o.). Ia positive cells (antigen-presenting cells) increased in the spleen adherent cells (SAC) obtained from immunized mice, whereas they decreased in the SAC obtained from carrageenan-treated mice. An increase of Ia positive cells occurred in the SAC of carrageenan-treated mice given ethylcysteine. Ethylcysteine (10-100 mg/kg, p.o.; on days -2 and -1) prevented both the suppression of the HPFC production and the decrease of the number of thymus lymphocytes and peripheral leukocytes induced by cyclophosphamide treatment (30 mg/kg, i.p.; on days -1 and 0). Lyt 1.2 positive cells (helper T cells) decreased in the spleen T cells of cyclophosphamide-treated mice, but increased in the spleen T cells from cyclophosphamide-treated mice give ethylcysteine. On the other hand, Thy 1.2 negative cells (B cells) did not increase in the spleen cells of cyclophosphamide-treated mice with or without ethylcysteine. These results suggest that ethylcysteine restores the immune response in immunosuppressed mice through the functions of macrophages and/or helper T cells.