Specific Anti-peptide Antibody to β Subunit of Chicken Thyrotropin: Production and Characterization

The unavailability of homologous antibodies to avian thyrotropin (TSH) has been a major hindrance in the study of avian reproduction and metabolism. Here we report the production and characterization of an anti-peptide antibody specific to chicken TSH β subunit. According to the cDNA sequence of chicken TSH β subunit, a synthetic peptide corresponding to the amino acid residues 35-50 (Tb3550; Asp-Ser-Asn-Gly-Lys-Lys-Leu-Leu-Leu-Lys-Ser-Ala-Leu-Ser-Gln-Asn) was prepared to produce polyclonal antibody in rabbits. This peptide sequence is highly specific to avian TSH β and was designed for the antibody to show no cross-reaction to pituitary and other chicken proteins with known amino acid sequences. Anti-Tb3550 recognized a 18.2-kDa band on immunoblot of the cephalic lobe homogenate, but not of the caudal lobe homogenate, of chicken anterior pituitary gland. Positive immunohistochemical staining with anti-Tb3550 was restricted to the cephalic lobe, whereas the cells positive to anti-chicken luteinizing hormone were scattered throughout the anterior pituitary. Anti-Tb3550 did not bind either to purified chicken luteinizing hormone or to follicle stimulating hormone preparation. These results indicate that this antibody specifically recognizes chicken TSH β subunit. This antibody should be useful for immunochemical study of avian TSH and for tracing TSH activity during the purification of the hormone.