Human B lymphocytes produce leukocyte interferon after interaction with foreign cells

Area of Science:

• Immunology
• Cell Biology

Background:

• Leukocyte interferon plays a crucial role in the innate immune response.
• The specific cell types responsible for interferon production upon encountering foreign antigens require further elucidation.

Purpose of the Study:

• To identify the primary human immune cell population responsible for producing leukocyte interferon when stimulated by xenogeneic or allogeneic tumor cells.
• To investigate the characteristics of interferon-producing cells.

Main Methods:

• Cocultivation of enriched human B-cell, T-cell, and plastic-adherent cell populations with tumor cells.
• Assay of interferon production levels.
• Cell surface marker analysis (nylon wool adherence, sheep erythrocyte rosetting).
• Functional assays using B-cell and T-cell mitogens.
• Immunological depletion using anti-IgM and complement.

Main Results:

• Enriched B-cell populations produced significantly higher levels of leukocyte interferon (1,000–10,000 U/ml) compared to T-cell or plastic-adherent populations (10–30 U/ml).
• Interferon-producing cells adhered to nylon wool and responded to B-cell mitogens (E. coli lipopolysaccharide) but not T-cell mitogens (staphylococcal enterotoxin A).
• Depletion of B-cells using anti-human IgM and complement abolished interferon synthesis.

Conclusions:

• In vitro studies strongly indicate that B-lymphocytes are the predominant cell type producing leukocyte interferon upon interaction with foreign cells.
• These findings suggest that B-lymphocytes are likely the primary producers of leukocyte interferon in vivo when encountering tumors or virus-infected cells.