DISPLAY OF AN INHIBIN EPITOPE IN A SURFACE-EXPOSED LOOP OF THE ESCHERICHIA-COLI HEAT-LABILE ENTEROTOXIN-B SUBUNIT

In vitro gene manipulation was used to develop a novel chimeric antige n consisting of the non-toxic B subunit (EtxB) of an E. coli enterotox in and the first 14 N-terminal amino acid residues of the carboxy-term inal portion of the alpha subunit of bovine inhibin (bINH(1-4)), Rabbi ts immunized subcutaneously (s.c.) or intravenously (i.v.) with EtxB:: bINH(1-14) with or without Freund's adjuvant, developed significant ti tres of antibodies that recognized an inhibin peptide fragment contain ing bINH(1-14) native inhibins, and EtxB during separate enzyme-linked immunosorbent assay (ELISA). Passive immunization of mice with the ra bbit anti-EtxB::bINH(1-14) serum increased concentrations of follicle- stimulating hormone (FSH) in serum twofold compared with controls, whe reas serum concentrations of luteinizing hormone (LH) were unaltered. Since FSH is the primary hormone from the pituitary gland that stimula tes ovarian follicle growth and spermatogenesis, the results of this s tudy demonstrate that EtxB::bINH(1-14) has potential as antigen for de velopment of inhibin-based fertility vaccines. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.