title: Mapping the antigenic determinants and reducing the immunogenicity of trichosanthin by site-directed mutagenesis.
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.
authors.affiliation: Department of Microbiology, Fourth Medical University of PLA, Xi'an, 710032, China.
authors.forename: Qunxing
authors.initials: Q
authors.lastname: An
authors.forename: Sanhua
authors.initials: S
authors.lastname: Wei
authors.forename: Shijie
authors.initials: S
authors.lastname: Mu
authors.forename: Xianqing
authors.initials: X
authors.lastname: Zhang
authors.forename: Yingfeng
authors.initials: Y
authors.lastname: Lei
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ning
authors.initials: N
authors.lastname: Jia
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Cheng
authors.forename: Ailing
authors.initials: A
authors.lastname: Fan
authors.forename: Zhidong
authors.initials: Z
authors.lastname: Li
authors.forename: Zhikai
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000818:Animals; D004247:DNA / Q000187:drug effects; D018604:Epitope Mapping; D015870:Gene Expression; D007073:Immunoglobulin E / Q000187:drug effects; D007074:Immunoglobulin G / Q000187:drug effects; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D012270:Ribosomes / Q000187:drug effects; D029778:Trichosanthes / Q000737:chemistry; D015978:Trichosanthin / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D007074:Immunoglobulin G; D007073:Immunoglobulin E; D015978:Trichosanthin; D004247:DNA