The in Vitro Absorption of Anti-Brain Radioantibodies with Brain Sediments: Some Unusual Properties and a Quantitative Method

Abstract

The absorption of ¹²⁵I-labeled anti-brain antibodies by brain sediment was studied in detail, and a solid-liquid partitioning effect, depending upon sediment/fluid ratios, was observed to take place during the time needed for antibody absorption. It was found that brain sediment, which is ordinarily insoluble when suspended in fluid and immediately centrifuged, would lose up to 30% of its weight to the fluid phase during a 1-hr incubation. A straight-line relationship between percentage of antibody absorbed by sediment and log of the sediment/fluid ratio was found to exist, with radioactive antibody acting as the indicator of the amount of antigen so partitioned. A revised quantitative technique for the absorption of radioantibody by brain sediments was developed on the basis of this study, and examples of its use in the assay of radioantibodies by brain sediments are given.