Anti-HIV effect of immunomodulating agent, levamisole, in vitro

An anthelminthic agent, levamisole, also known as a potent immunomodulator, has been successfully used for adjuvant therapy of malignancies and chronic infections underlined by immunodeficiency. We have tested the effect of this drug on de novo viral infection by exposing MT-4 T lymphocytes to HIV in the presence of serial ten-fold dilutions of levamisole (range 10(-3)-10(-9) M). The results indicate that 50% reduction in viral infectivity (IC50) of levamisole starts from as low as 10(-7) M, whereas even the highest millimolar dose of the drug has not shown any appreciable cytotoxicity. Although the mechanism of levamisole action remains unknown, our observation in vitro suggests that levamisole, a clinically established immunomodulator, can be potentially effective for treatment of HIV infection.