Human brain lectin immunoreactive material in cerebrospinal fluids determined by enzyme immunoassay (EIA).

A sensitive enzyme immunoassay (EIA) micromethod is described which can measure levels of a 14 kDa human brain lectin (HBL) in the cerebrospinal fluid (CSF) of patients submitted to CSF examination. The assay is based on the use of a polyclonal antibody to HBL and the simultaneous application of biotinylated and unlabeled HBL. Biotin was then reacted with a streptavidin-peroxidase (Strep-HRP) conjugate and the bound enzyme quantified with the substrate orthophenylenediamine (OPD). The assay requires only 50 microliters of CSF and is very sensitive: as little as 6 ng/ml of HBL 14 can be detected. In a blind-test screening, the mean (+/- SEM) concentration of the HBL immunoreactive material (HIM) in CSF was determined to be 72.4 +/- 6.6 ng/ml. Our results indicate that EIA measurement of HIM levels in the CSF may find useful applications in elucidating the involvement of HBL in the physiopathology of human nervous system (NS).

Soluble heparin-binding lectins from human brain: purification, specificity and relationship to an heparin-binding growth factor.

1. An heparin-binding lectin activity was detected in soluble extracts of human brain. Three polypeptide chains were purified by affinity chromatography on heparin-Sepharose. Their Mrs estimated by polyacrylamide gel electrophoresis were 13,000, 14,500 and 16,000. 2. Several glycosaminoglycans were potent inhibitors of their hemagglutination activity. 3. From the pool of purified lectins three peaks were separated by reversed-phase high-performance liquid chromatography. They were indistinguishable by activity criteria (hemagglutination, stimulation of endothelial cell growth), and immunological relationship was found between one of them and acidic fibroblast growth factor (aFGF).