title: Antibody-directed enzyme prodrug therapy (ADEPT).
abstract: A conjugate of the bacterial enzyme carboxypeptidase G2 and the F(ab)(2) fragment of the anti-CEA monoclonal antibody A5B7 was directed in vitro at the human colon tumour cell line LS174T and the human non-small cell lung line COR-L23. Indirect immunofluorescence microscopy was used to show that the conjugate bound to LS174T cells but not to COR-L23. The cytotoxicity generated by addition of a phenol mustard prodrug to each cell line after pre-incubation with conjugate was found to be significantly greater for LS174T cells (IC50=0.24 mu M) than COR-L23 cells (IC50=108 mu M). However, for a 1:1 mixture of these cells an IC50, of 3.4 mu M was obtained. These data show that phenol mustard released by a localised conjugate can exert a bystander effect on neighbouring cells to which the conjugate does not bind.
authors.affiliation: CHARING CROSS HOSP,DEPT MED ONCOL,CANC RES CAMPAIGN LABS,LONDON W6 8RF,ENGLAND. CHARING CROSS HOSP,DEPT MED ONCOL,CATHERINE GRIFFITHS CANC RES LAB,MELANOMA UNIT,LONDON W6 8RF,ENGLAND. PUBL HLTH LAB SERV,CTR APPL MICROBIOL & RES,SALISBURY SP4 0JG,WILTS,ENGLAND.
authors.forename: B
authors.initials: B
authors.lastname: Retta
authors.forename: P
authors.initials: P
authors.lastname: Burke
authors.forename: A
authors.initials: A
authors.lastname: Photiou
authors.forename: R
authors.initials: R
authors.lastname: Melton
authors.forename: E
authors.initials: E
authors.lastname: Enoamooquaye