Influence of the antileukemic and anti-human immunodeficiency virus agent avarol on selected immune responses in vitro and in vivo.

The effect of the antileukemic and anti-HIV agent avarol on the lymphoid system was studied both in vitro and in vivo. Radioactively labelled avarol ([3H]-dihydroavarol) was found to accumulate in vitro in the cytoplasmic compartment primarily of T-lymphocytes and not of B-lymphocytes. Avarol increased significantly the IgG and IgM production by cultures of human lymphoid cells (unseparated) in vitro and slightly the number of plaque forming cells in vivo in spleen of mice. Moreover, a pretreatment of mice with avarol resulted in a higher [3H]-dThd incorporation rate in both macrophage-containing and macrophage-depleted lymphocyte cultures in vitro. The stimulatory influence of avarol on humoral immune responses is not accompanied by a change of the antibody-mediated hypersensitivity reaction, as measured by the Arthus reaction. No significant influence of avarol on the cellular immune system in vivo (rats or mice) was found, as taken from studies on delayed-type hypersensitivity reactions to sheep red blood cells and to oxazolone. The in vitro and animal data indicate that avarol combines useful properties (anti-HIV efficiency in vitro and augmentation of humoral immune responses) to consider it as a potential anti-AIDS agent.