1. Mapping the antigenic determinants and reducing the immunogenicity of trichosanthin by site-directed mutagenesis
- Author
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Xian-Qing Zhang, Yingfeng Lei, Ning Jia, Zhi-kai Xu, Qunxing An, Shijie Mu, Sanhua Wei, Wei Zhang, Ailing Fan, Xiaodong Cheng, and Zhidong Li
- Subjects
Trichosanthin ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Mutant ,Human immunodeficiency virus (HIV) ,Gene Expression ,Mutagenesis (molecular biology technique) ,Trichosanthes ,Biology ,medicine.disease_cause ,Mice ,Antigen ,medicine ,Animals ,Pharmacology (medical) ,Site-directed mutagenesis ,Molecular Biology ,Ribosome-inactivating protein ,Immunogenicity ,fungi ,Biochemistry (medical) ,DNA ,Cell Biology ,General Medicine ,Immunoglobulin E ,Virology ,Immunoglobulin G ,Mutation ,Mutagenesis, Site-Directed ,Ribosomes ,Epitope Mapping - Abstract
Trichosanthin (TCS) is a type I ribosome-inactivating protein (RIP) possessing multiple pharmacological properties. One of its interesting properties is to inhibit human immunodeficiency virus (HIV) replication but its strong immunogenicity has limited the repeated clinical administration. To map the antigenic determinants and reduce the immunogenicity of TCS, two potential antigenic sites (YFF81-83 and KR173-174) were identified by computer modeling, and then three TCS mutants namely TCS(YFF81-83ACS), TCS(KR173-174CG), and TCS(YFF-KR) were constructed by site-directed mutagenesis. The RI activity and DNase-like activity of the three constructed TCS mutants were similar to natural TCS but with much lower immunogenicity. Results suggested that the two selected sites are all located at or near the antigenic determinants of TCS. In toxicity studies, the LD(50) of the three TCS mutants was not different from natural TCS. These findings would be useful in designing a better therapeutic agent for AIDS.
- Published
- 2006