Drug -- protein interactions in vitro. Effect of levamisole on human serum albumin.

The actions of (--)-2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b]thiazole (levamisole) on human serum, human serum albumin (HSA) and bovin serum albumin (BSA) were studied. Analysis by polyacrylamide gel electrophoresis and immunodiffusion on gelose revealed the presence of aggregate forms of albumin in the human serum and a quantitative variation of polymeric forms with supplementary induced forms in case of HSA and BSA. The effect of other compounds with levamisole-like chemical groups including SH group or thiazolidine ring was investigated in similar conditions; aggregates were not observed. When the human serum was treated with these compounds, analysis by immunoelectrophoresis did not indicate a morphological change of lines of precipitate of immunoglobulins G and A previously described for levamisole action. The polymerization of albumin induced by the levamisole has been discussed. The whole of the data suggests that this drug may act in a specific way on the protein structure.