The identification of peptide sequences of human chorionic gonadotropin containing a conformational epitope.
A series of overlapping peptides were synthesized representing the entire amino acid sequence of the beta-subunit of human chorionic gonadotropin (hCG) and these were reacted with a monoclonal antibody shown to be specific for hCG. One linear peptide (residues 40-52 of the sequence) reacted significantly with the monoclonal antibody but a conjugate of this peptide to diphtheria toxoid (DT) failed to elicit significant levels of antibodies reactive to hCG in rabbits. The subsequent preparation of an extended peptide (residues 38-57) in which the two cysteines were oxidized to form a loop peptide yielded a highly immunogenic antigen when conjugated to DT. Antibody levels reactive with hCG from loop peptide immunizations of rabbits exceeded those found after immunization with a 37 residue peptide representing the carboxyl terminus of the beta-hCG subunit. The antisera did not react with pituitary glycoprotein hormones with similar sequences.
Stevens
V C
VC
Chou
W S
WS
Powell
J E
JE
Lee
A C
AC
Smoot
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D006063:Chorionic Gonadotropin / Q000032:analysis / Q000276:immunology*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D004168:Diphtheria Toxoid / Q000276:immunology; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis / Q000138:chemical synthesis* / Q000276:immunology; D010456:Peptides, Cyclic / Q000276:immunology; D011817:Rabbits
D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D004168:Diphtheria Toxoid; D000939:Epitopes; D010446:Peptide Fragments; D010456:Peptides, Cyclic