| Abstract: | When added to cultures of human peripheral blood lymphocytes, ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) inhibited antigen- and mitogen-induced proliferative responses as determined by 3H]thymidine incorporation. Dose-dependent suppressive effects were obtained when concentrations of 5 to 60 microgram of ribavirin per ml were added at culture initiation or up to 96 h thereafter. Ribavirin inhibited 3H]uridine and 3H]leucine incorporation by concanavalin A-activated and normal lymphocytes although not as severely as deoxyribonucleic acid synthesis. The capacity of ribavirin to interfere with lymphoproliferative responses was entirely reversed by guanosine and, to a lesser extent, by adenosine and xanthosine. These studies demonstrate that ribavirin is a reversible inhibitor of lymphocyte nucleic acid synthesis and suggest that the drug may be immunosuppressive when administered in vivo. |
