Veterinary Immunology and Serology

MUCOSAL IMMUNE SYSTEM

• The mucosal surfaces of the gastro intestinal tract, respiratory tract, genital tract and oral cavity represent a vast surface area which is vulnerable to invasion and colonization by many micro organisms. Defense in these membrane surfaces is provided by organized lymphoid tissue, collectively known as mucosa associated lymphoid tissue (MALT).
• In G-I tract, lymphocytes are found in large numbers in three main regions: 
• Within epithelial layer (intraepithelial lymphocytes),
• Scattered throughout the lamina propria and
• In payer’s patches of lamina propria.
• Intra epithelial lymphocytes are mainly T cells (CD8⁺).
• The follicles contain B cells, macrophages, dendrite cells. B cells express IgM in the periphery of the follicle and IgA in the germinal centre.
• T cells predominate in inter and para follicular regions.