Effect of cysteine ethylester hydrochloride (CystaninR) on host defense mechanisms. (IV). Potentiating effects on the function of peritoneal or spleen macrophages.

L-Cysteine ethylester hydrochloride (ethylcysteine; 30 mg/kg, p.o.) increased the number of la-positive cells (antigen presenting cells) in spleen adherent cells (SAC) and that of Lyt 1.2-positive cells (helper T cells), but not that of Lyt 2.2-positive cells (suppressor T cells) of C57BL/6 mice immunized with sheep red blood cells. The production of hemolytic plaque forming cells (HPFC) in spleens of syngeneic recipient mice was enhanced by the transfer of SAC or spleen lymphocytes of the donor mice pretreated with ethylcysteine. This drug augmented phagocytosis of yeast particles by peritoneal macrophages of ICR mice at concentrations of 1-100 microM. In ex vivo experiments, this drug (30 mg/kg, p.o.) augmented the phagocytosis of yeast particles by mouse macrophages and showed a tendency to increase the macrophage number in the peritoneal cavity. Ethylcysteine (30 mg/kg, p.o.) significantly accelerated the decrease of viable E. coli number in the liver of normal mice 2 and 48 hr after challenge. Furthermore, this drug at the same dose restored the suppression of the decrease of E. coli number in the blood and liver of mice treated with cyclophosphamide (200 mg/kg, i.p.). These results suggest that ethylcysteine augments the functions of macrophages in vitro and ex vivo, and these enhancing effects may lead to the enhancement of host resistance to infections in compromised hosts.