The human chorionic gonadotropin-ß arginine68 to glutamic acid substitution fixes the conformation of the C-terminal Peptide
Article
Charrel-Dennis, M., Terrazzini, N., McBride, J., Martensen, P., Justesen, J., Berger, P., Lapthorn, A., Kelly, C., Roitt, I., Delves, P. and Lund, T. 2005. The human chorionic gonadotropin-ß arginine68 to glutamic acid substitution fixes the conformation of the C-terminal Peptide. Molecular Endocrinology. 19 (7), pp. 1803-1811. https://doi.org/10.1210/me.2004-0109
Type | Article |
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Title | The human chorionic gonadotropin-ß arginine68 to glutamic acid substitution fixes the conformation of the C-terminal Peptide |
Authors | Charrel-Dennis, M., Terrazzini, N., McBride, J., Martensen, P., Justesen, J., Berger, P., Lapthorn, A., Kelly, C., Roitt, I., Delves, P. and Lund, T. |
Abstract | Wild-type human chorionic gonadotropin (hCG) has been used as a contraceptive vaccine. However, extensive sequence homology with LH elicits production of cross-reactive antibodies. Substitution of arginine68 of the ß-subunit (hCGß) with glutamic acid (R68E) profoundly reduces the cross-reactivity while refocusing the immune response to the hCGß-specific C-terminal peptide (CTP). To investigate the molecular basis for this change in epitope usage, we immunized mice with a plasmid encoding a truncated hCGß-R68E chain lacking the CTP. The animals produced LH-cross-reactive antibodies, suggesting that the refocused immunogenicity of R68E is a consequence of epitope masking by a novel disposition of the CTP in the mutant rather than a structural change in the cross-reactive epitope region. This explanation was strongly supported by surface plasmon resonance analysis using a panel of anti-hCGß-specific and anti-hCGß/LH cross-reactive monoclonal antibodies (mAbs). Whereas the binding of the LH cross-reactive mAbs to hCGß-R68E was eliminated, mAbs reacting with hCGß-specific epitopes bound to hCGß and hCGß-R68E with identical affinities. In a separate series of experiments, we observed that LH cross-reactive epitopes were silent after immunization with a plasmid encoding a membrane form of hCGß-R68E, as previously observed with the soluble mutant protein itself. In contrast, the plasmid encoding the soluble secreted form of hCGß-R68E evoked LH cross-reactive antibodies, albeit of relatively low titer, suggesting that the handling and processing of the proteins produced by the two constructs differed. |
Research Group | Biomarkers for Cancer group |
Publisher | The Endocrine Society |
Journal | Molecular Endocrinology |
ISSN | 0888-8809 |
Publication dates | |
Jul 2005 | |
Publication process dates | |
Deposited | 02 Feb 2010 |
Output status | Published |
Digital Object Identifier (DOI) | https://doi.org/10.1210/me.2004-0109 |
Language | English |
https://repository.mdx.ac.uk/item/822v3
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