Activity of recombinant mitogillin and mitogillin immunoconjugates.
1992; Elsevier BV; Volume: 267; Issue: 23 Linguagem: Inglês
10.1016/s0021-9258(18)42060-1
ISSN1083-351X
AutoresMarc Better, Susan L. Bernhard, Shunshun Lei, Dianne M. Fishwild, Stephen F. Carroll,
Tópico(s)Microbial infections and disease research
ResumoA synthetic gene for the Aspergillus protein toxin mitogillin has been synthesized and expressed in Escherichia coli.The recombinant mitogillin is a potent inhibitor of protein synthesis in vitro with an IC6,, of 9.7 PM.Immunoconjugates of recombinant mitogillin derivatized with S-acetylmercaptosuccinic anhydride and 5-methyl-2-iminothiolane modified H65 antibody kill T cell lines and peripheral blood mononuclear cells expressing the human CD5 surface antigen.Native mitogillin contains 4 cysteine residues which form two disulfide pairs (Fernandez-Luna, J. L., Lopez-Otin, C., Soriano, F., and Mendez, E. (1985) Biochemistry 24, 861-867).Three derivatives of mitogillin have been assembled which substitute alanine residues for cysteine residues 5, 147, or 5 and 147.Each of these molecules retains the ability to inhibit protein synthesis in vitro with at most a 2-fold reduction in activity.The derivative mitogillinc14,A can be conjugated to 5- methyl-2-iminothiolane-modified H65 antibody directly without pretreatment with S-acetylmercaptosuccinic anhydride, and the immunoconjugate is active against HSB2 cells.Genetic manipulation of toxin genes to expose an accessible cysteine residue into a recombinant product can thus be used to generate immunotoxins without initial derivatization by nonspecific cross-linking reagents.
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