Non-major histocompatibility complex alloantigen genes affecting immunity

Area of Science:

• Immunogenetics
• Avian immunology
• Animal genetics

Background:

• Alloantigens are genetically determined cell-surface molecules crucial for immune recognition.
• Twelve distinct families of alloantigens (A-L, P, R) have been identified, with most genes segregating independently.
• Previous studies suggest associations between certain alloantigen systems and immune responses.

Purpose of the Study:

• To investigate the influence of specific alloantigen systems on various immune responses in chickens.
• To identify correlations between alloantigen gene frequencies and traits like disease resistance, antibody production, and organ size.
• To establish a method for simultaneously testing multiple alloantigen systems.

Main Methods:

• Selection experiments over multiple generations were conducted to alter gene frequencies of specific alloantigen systems.
• Immune responses were assessed by measuring susceptibility to coccidiosis, response to SRBC immunization, bursa of Fabricius size, macrophage nitrite production, and cytokine IL-6 production.
• Genotypes of alloantigen systems were compared within families for traits such as monocyte phagocytosis and disease outcome.
• A novel experimental procedure was developed to simultaneously test immune responses of 9 alloantigen systems.

Main Results:

• Selection experiments revealed distinct changes in gene frequencies for A-E, C, D, I, and L alloantigen systems, correlating with immune responses.
• Specific alloantigen systems (C, D, I, L) showed significant associations with macrophage function (nitrite and IL-6 production) and bursa size.
• The L system demonstrated effects on monocyte phagocytosis, coccidiosis susceptibility, and responses to SRBC and Brucella abortus.
• The P alloantigen system was linked to differences in monocyte phagocytosis.
• A method for simultaneous testing of 9 alloantigen systems was successfully established.

Conclusions:

• Alloantigen systems play a significant role in modulating diverse immune responses in chickens.
• Specific alloantigens are associated with disease resistance, antibody production, and cellular immune functions.
• The established multi-system testing procedure provides a valuable tool for future immunogenetic research in poultry.