The immune response to GHRH, relationship to conformation.
Antibodies to GHRH1-44, GHRH1-29, and proinsulin were induced in guinea pigs. GHRH1-44 forms 7 S and 10 S complexes with antibodies. It is a divalent antigen. The sequence 30-44 bound 85% of the antibodies to GHRH1-44 with high affinity (3.8 +/- 0.9 x 10(9) l/mol). The fragment 1-29 bound with low affinity (0.6 +/- 0.3 x 10(9) l/mol) 15% of the antibodies (2p less than 0.001). Antibodies to GHRH1-29 had low affinity towards the native hormone (0.4 +/- 0.2 x 10(9) l/mol) and the region 1-29 (0.3 +/- 0.2 x 10(9) l/mol). Antibodies to proinsulin bound linear C-peptide with lower affinity (0.3 +/- 0.2 x 10(9) l/mol) than the C-peptide loop in proinsulin (3.4 +/- 0.9 x 10(9) l/mol). It is concluded that the conformation of the epitopes on the sequence 1-29, recognized during the immune response, i.e. on the cell membrane, is different from the conformation of GHRH1-29 or GHRH1-44 in aqueous solution.
Petersen
K G
KG
Abteilung Klinische Endokrinologie, Medizinische Univ.-Klinik, Freiburg, Germany.
Zeisel
H J
HJ
Kerp
L
L
D000818:Animals; D000917:Antibody Formation; D002352:Carrier Proteins / Q000276:immunology; D002462:Cell Membrane / Q000276:immunology; D013007:Growth Hormone-Releasing Hormone / Q000276:immunology*; D006168:Guinea Pigs; D007074:Immunoglobulin G / Q000276:immunology; D007457:Iodine Radioisotopes; D008297:Male; D011384:Proinsulin / Q000276:immunology; D011487:Protein Conformation
D002352:Carrier Proteins; D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; C020723:citrate-binding transport protein; D013007:Growth Hormone-Releasing Hormone; D011384:Proinsulin