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Title: Cloning and expression of recombinant, functional ricin B chain

Journal Article · · Proc. Natl. Acad. Sci. U.S.A.; (United States)

The cDNA encoding the B chain of the plant toxin ricin has been cloned and expressed in monkey kidney COS-M6 cells. The recombinant B chain was detected by labeling the transfected cells with (/sup 35/S)methionine and (/sup 35/S)-cysteine and demonstrating the secretion of a protein with a M/sub r/ of 30,000-32,000 that was not present in the medium of mock-transfected COS-M6 cells. This protein was specifically immunoprecipitated by an anti-ricin or anti-B-chain antibody and the amount of recombinant B chain secreted by the COS-M6 cells was determined by a radioimmunoassay. Virtually all of the recombinant B chain formed active ricin when mixed with native A chain; it could also bind to the galactose-containing glycoprotein asialofetuin as effectively as native B chain.These results indicate that the vast majority of recombinant B chains secreted into the medium of the COS-M6 cells retain biological function

Research Organization:
Univ. of Texas Health Science Center, Dallas (USA)
OSTI ID:
5298007
Journal Information:
Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:16
Country of Publication:
United States
Language:
English