Final answer:
In Hashimoto's thyroiditis, autoantibodies against thyroid peroxidase (TPO) and thyroglobulin are most prevalent, leading to the destruction of the thyroid gland and causing hypothyroidism.
Step-by-step explanation:
The antibodies most prevalent in Hashimoto's thyroiditis are directed against thyroid-specific proteins, such as thyroid peroxidase (TPO) and thyroglobulin. This autoimmune disorder leads to the destruction of the thyroid gland and the subsequent hypothyroidism. Hashimoto's thyroiditis is characterized by the presence of autoantibodies that attack the thyroid gland, specifically the thyroid-stimulating hormone (TSH) receptors, which can result in an overstimulation in other thyroid conditions but in Hashimoto's leads to damage and decreased function of the thyroid.