Immune Reactivities of Antibodies against Glycolipids. I.

摘要

A new, simple technique is described for purifying specific anti-glycolipid (Galactocerebroside) antibodies from antiserum. The antibodies first were absorbed to galactocerebroside-containing liposomes and then were recovered, after washing the liposomes, by elution with 1 M NaI, or by extraction with a saline-chloroform mixture. Depending on the antiserumused, this procedure resulted in approximately a 175-fold to 3800-fold purification of antibodies from whole serum when calculated on an activity/protein basis. The antibodies tested for activity by means of complement-dependent glucose release from separate Galctocerebroside-containing indicator liposomes. It was found that the hydrophobic portions both of the galactocerebroside and the surrounding phospholipids had an influence on antibody binding. The relative-anti-galactocerebroside activity, as determined by liposomal glucose release, was directly related to the galactocerebroside fatty acyl chain length. This suggested that the presence of a longer fatty acyl chain in the glycolipid molecule made the carbohydrate more accessible to binding with specific antibody. Furthermore, the degree of adsorption of antibody activity from the antiserum was progressively decreased when the hydrophobic region of the phospholipid membrane was increased due to the presence of phospholipids containing progressively longer fatty acids. These results were consistent with the hypothesis that under certain conditions the immunologically-active group on galactocerebroside may be partially 'buried' in the phospholipid bilayer and may be less available for antibody binding.