Two molecular species of mouse L cell interferon differing in lectin binding

Area of Science:

• Biochemistry
• Immunology
• Glycobiology

Background:

• Interferons are crucial signaling proteins in the immune system.
• L cell interferon exists in two main molecular species: F (24 kDa) and S (36 kDa).
• Lectins are proteins that bind carbohydrates, offering a means to study glycoprotein structures.

Purpose of the Study:

• To investigate the binding interactions of L cell interferon species with specific lectins.
• To differentiate the two molecular species of L cell interferon based on their carbohydrate structures.
• To assess the glycoprotein nature and heterogeneity of L cell interferon.

Main Methods:

• Affinity chromatography using Wistaria floribunda agglutinin (WFA)-Sepharose and Concanavalin A (Con A)-Sepharose.
• Elution of bound interferon species using specific sugar inhibitors (D-galactose, alpha-methyl-D-glucoside) and pH adjustment.
• Analysis of binding efficiency and elution profiles of L cell interferon F and S species.

Main Results:

• The S species of L cell interferon (36 kDa) bound efficiently to WFA-Sepharose, indicating distinct carbohydrate structures compared to the F species.
• Both F and S interferon species showed partial binding to Con A-Sepharose, suggesting that at least some F species are glycoproteins.
• Heterogeneity in lectin binding affinity was observed for both F and S interferon species.

Conclusions:

• Significant differences in carbohydrate structure exist between the F and S molecular species of L cell interferon.
• Both interferon species exhibit heterogeneity in their glycosylation patterns and lectin-binding properties.
• Lectins like WFA and Con A are valuable tools for characterizing interferon glycoproteins and their structural variations.