Neonatal appendectomy impairs mucosal immunity in rabbits

Area of Science:

• Immunology
• Gastroenterology

Background:

• The appendix's role in the immune system, particularly in the gut, is not fully understood.
• Investigating the appendix's contribution to immunoglobulin production is essential for understanding gut immunity.

Purpose of the Study:

• To determine the impact of neonatal appendectomy on immunoglobulin levels and plasma cell populations in the rabbit gut and serum.
• To elucidate the appendix's role in intestinal immunity, specifically IgA production.

Main Methods:

• Neonatal appendectomy was performed on rabbits, followed by immunization with ovalbumin (OVA).
• Serum and duodenal immunoglobulin levels (total and OVA-specific) were quantified using ELISA.
• Plasma cell counts in the small intestine were assessed via double immunofluorescent staining.

Main Results:

• Appendectomy significantly reduced total intestinal IgA, IgM, and IgG, but not serum Ig levels.
• Ovalbumin-specific IgA and IgG in both the gut and serum were markedly decreased post-appendectomy.
• A significant reduction in total IgA+ and OVA-reactive IgA+ plasma cells was observed in appendectomized rabbits.

Conclusions:

• The rabbit appendix is critical for seeding the intestinal lamina propria with plasma cell precursors, particularly those producing IgA.
• Appendectomy severely impairs the gut's ability to produce both total and antigen-specific immunoglobulins.
• These findings highlight the appendix's substantial contribution to mucosal immunity.