Biological properties of human leukocyte interferon components

Area of Science:

• Immunology
• Virology
• Biochemistry

Background:

• Human leukocyte interferon (HuIFN-α) is a crucial antiviral protein.
• Previous studies suggested heterogeneity within HuIFN-α preparations.
• Understanding interferon subtypes is vital for therapeutic applications.

Purpose of the Study:

• To purify and characterize human leukocyte interferon.
• To investigate the structural and antigenic similarities between different interferon components.
• To determine the antiviral efficacy and neutralization profiles of purified interferon components.

Main Methods:

• Affinity chromatography using immobilized anti-interferon globulins.
• SDS-Sephadex filtration for purification.
• Adsorption chromatography on hydroxylapatite.
• Polyacrylamide gel electrophoresis (PAGE).
• Antiviral protection assays in bovine, porcine, and murine cells.
• Neutralization assays with specific antisera.
• Immunization studies in mice.

Main Results:

• Human leukocyte interferon was purified ~1000-fold.
• Two distinct components (major and minor) were resolved.
• Both components exhibited similar antiviral activity against various cell types.
• Antiviral activity was equally susceptible to beta-mercaptoethanol reduction.
• Components were neutralized by anti-leukocyte interferon but not by anti-fibroblast interferon serum.
• Mice immunized with one component developed antibodies to both, but not to fibroblast interferon.

Conclusions:

• The two purified human leukocyte interferon components possess very similar antiviral and antigenic properties.
• These findings suggest minimal structural and antigenic dissimilarity between the components.
• The results support the classification of these components as closely related subtypes of human leukocyte interferon.