Lectin binding sites in the choroid plexus and choroid plexus papillomas

Area of Science:

• Neuroscience
• Biochemistry
• Histopathology

Background:

• The choroid plexus and its tumors exhibit specific cell surface glycoconjugates.
• Sialomucopolysaccharides are key components of the cell surface in these tissues.
• Understanding these surface markers is crucial for differential diagnosis.

Purpose of the Study:

• To characterize the cell surface glycoconjugates of normal choroid plexus and choroid plexus papillomas.
• To investigate the potential of specific lectins for identifying these glycoconjugates.
• To explore the diagnostic utility of histochemical techniques in distinguishing choroid plexus papillomas from other brain tumors.

Main Methods:

• Histochemical staining using colloidal iron (Hale reaction) to detect sialomucopolysaccharides.
• Enzymatic pretreatment with neuraminidase to remove sialic acid.
• Application of FITC- or rhodamine-labelled lectins, specifically PNA (Arachis hypogaea) and RCA (Rhicinus communis), to identify specific oligosaccharide receptors.
• Comparative analysis of staining patterns between normal choroid plexus, papillomas, and other neoplasms.

Main Results:

• The cell surfaces of normal choroid plexus and choroid plexus papillomas are coated with sialomucopolysaccharides, reactive to the Hale stain.
• Neuraminidase treatment removes sialic acid, leading to a negative Hale reaction.
• Specific lectin receptors, including those for PNA and RCA, are demonstrable on these cell surfaces.
• The identified oligosaccharide receptors show similarity to Thomsen-Friedenreich antigens.

Conclusions:

• The cell surface composition of choroid plexus and its tumors can be characterized using histochemical methods.
• The presence of specific lectin-binding sites suggests potential immunologic significance, possibly in infections.
• Histochemical techniques are valuable tools for the differential diagnosis of choroid plexus papillomas versus metastatic carcinomas and papillary ependymomas.