Thyroid-Specific Autoantibodies Studied by Passive Cutaneous Anaphylaxis of Guinea Pig.

1. Passive cutaneous anaphylaxis of the guinea pig has been successfully used to study thyroid autoantibodies of rabbit, guinea pig, and man. 2. The thyroid autoantibody proved to be specific for the homologous antigen (thyroid extract and purified derivative) and did not give cross reactions with thyroid extracts of other species. 3. Five human sera with high titer of thyroid autoantibody were studied. The antibody was completely neutralized by human thyroid extract or human thyroglobulin, but was not significantly affected by any of a variety of other organ extracts or of iodinated amino acids, again indicating the specificity of this type of antibody.