| Abstract: | Electroimmunodiffusion methods of Laurell and radial immunodiffusion method of Mancini are compared for the qualitative and quantitative analysis of native and desialylated alpha 1-acid glycoprotein. Samples are incubated under different conditions at decreasing pH (3.5 to 0.5 pH units), with increasing ionic strength and with neuraminidase during different time intervals. Results show a pronounced decrease in electrophoretic mobility of alpha 1-acid glycoprotein treated either with acidic reagents or with neuraminidase (ionic strength has no effect). Such a procedure might involve chemical or enzymatic hydrolysis by which sialyl residues are removed. This hydrolysis implicates lower results in the estimation of the desialylated glycoprotein by electroimmunodiffusion. On the other hand, the amounts of alpha 1-acid glycoprotein evaluated by radial immunodiffusion are not modified after incubation. This is expected since diffusion and antigenic properties are not related to the sialic acid content. The data suggest that radial immunodiffusion, less accurate and sensitive than electroimmunodiffusion, is nevertheless more adequate for estimating native and desialylated alpha 1-acid glycoprotein. |
