Relation between the major histocompatibility (B) locus and autoimmune thyroiditis in obese chickens

Area of Science:

• Avian immunology
• Autoimmune disease research
• Genetics of disease resistance

Background:

• Obese strain chickens are a model for autoimmune thyroid disease.
• Thyroid autoimmunity involves autoantibodies and lymphocytic infiltration.
• The major histocompatibility (B) locus plays a role in immune responses.

Purpose of the Study:

• To investigate the role of major histocompatibility (B) locus alleles in the development of thyroid autoimmunity in obese strain chickens.
• To correlate specific B locus genotypes with the severity of autoimmune pathology and autoantibody production.

Main Methods:

• Monitoring of autoantibodies to thyroglobulin in aging obese strain chickens.
• Histopathological examination of thyroid tissues to assess lymphocytic infiltration.
• Genotyping of birds for major histocompatibility (B) locus alleles (B(1) and B(4)).

Main Results:

• Obese strain chickens develop circulating autoantibodies to thyroglobulin and thyroid lymphocytic infiltration with age.
• High gene frequencies of B(1) and B(4) alleles were observed at the major histocompatibility (B) locus.
• Birds with B(1)B(1) and B(1)B(4) genotypes exhibited greater thyroid pathology and higher autoantibody titers compared to B(4)B(4) siblings.

Conclusions:

• Major histocompatibility (B) locus genotype significantly influences the development and severity of autoimmune thyroid disease in obese strain chickens.
• The B(1) allele is associated with increased susceptibility to and pathology of autoimmune thyroiditis.
• These findings highlight the genetic control of autoimmune responses in a poultry model.