Are Actinomyces viscosus antigens B cell mitogens?

Area of Science:

• Immunology
• Microbiology
• Biochemistry

Background:

• Actinomyces viscosus is a bacterium known to interact with the host immune system.
• Understanding microbial components that modulate lymphocyte activity is crucial for immunology.

Purpose of the Study:

• To investigate the mitogenic potential of Actinomyces viscosus extracellular heteroglycan (ECHG) and sonicated cell supernatant (SCS).
• To determine the specific lymphocyte populations targeted by these microbial components.

Main Methods:

• Lymphocyte proliferation assays using spleen and thoracic duct cells from germfree rats.
• Testing with spleen cells from conventional "nude" mice to assess T-cell independence.
• Analysis of B cell activation via plaque-forming cell assays against TNP-SRBC.
• Investigating the effect of alkaline hydrolysis on the mitogenic properties of ECHG.

Main Results:

• Both ECHG and SCS induced significant lymphocyte proliferation in rat cells.
• ECHG's mitogenicity was reduced after alkaline hydrolysis in rat lymphocytes but abolished in nude mouse lymphocytes.
• Spleen cells from rats produced plaque-forming cells against TNP-SRBC, indicating B cell activation.
• The results suggest that the mitogenic effects are primarily on B cells.

Conclusions:

• Actinomyces viscosus ECHG and SCS possess potent B cell mitogenicity.
• The structural integrity of ECHG is important for its mitogenic activity on B cells.
• These findings contribute to understanding bacterial modulation of the host immune system, specifically B cell responses.