The tonsillar immune system: its response to exogenous antigens

Area of Science:

• Immunology
• Pathology
• Anatomy

Background:

• The palatine tonsil is unique as a lymphoid organ directly exposed to the external environment.
• This exposure suggests a significant role in defending against exogenous antigens.
• However, tonsils can also be sites for secondary diseases like focal infections.

Purpose of the Study:

• To investigate the palatine tonsil's response to an introduced antigen, horseradish peroxidase (HRP).
• To examine the effects of this tonsil response on regional lymph nodes and distant organs like the kidney.
• To understand the immunological significance of the tonsil in relation to the broader immune system and focal infection.

Main Methods:

• Horseradish peroxidase (HRP) was introduced into tonsil crypts.
• Phagocytosis of HRP by macrophages and their migration were observed.
• Antibody-producing cells were identified in the tonsil and regional lymph nodes.
• Electron microscopy was used in a long-term, repeated immunization study to assess glomerular changes.

Main Results:

• HRP was phagocytosed by macrophages within the tonsil and migrated to regional lymph nodes.
• Anti-HRP antibody-producing cells were found in both the tonsil and regional lymph nodes.
• Long-term, repeated HRP exposure led to epithelial foot process fusion and reduced glomerular anionic charge.

Conclusions:

• The palatine tonsil plays a crucial role in immune defense against external antigens.
• Tonsil immune responses have systemic effects, influencing regional lymph nodes and distant organs.
• Dysfunction or overwhelming exposure can lead to the tonsil becoming a primary site for focal infections.