Production of phage-displayed anti-idiotypic antibody single chain variable fragments to MG7 monoclonal antibody directed against gastric carcinoma.
OBJECTIVE
To generate phage-displayed anti-idiotypic antibody single chain variable fragments (anti-Id ScFv) to MG7 monoclonal antibody (McAb) directed against gastric carcinoma so as to lay a foundation for developing anti-Id ScFv vaccine of the cancer.


METHODS
Balb/c mice were immunized i.p. with MG7 McAb conjugated with keyhole limpet hemocyanin (KLH), and mRNA was isolated from the spleens of the immunized mice. Heavy and light chain (VH and VL) genes of antibody were amplified separately and assembled into ScFv genes with a linker DNA by PCR. The ScFv genes were ligated into the phagemid vector pCANTAB5E and the ligated sample was transformed into competent E. coli TG1. The transformants were infected with M13K07 helper phage to yield recombinant phages displaying ScFv on the tips of M13 phage. After 4 rounds of panning with MG7, the MG7-positive clones were selected by ELISA from the enriched phages. The types of the anti-Id ScFv displayed on the selected phage clones were preliminarily identified by competition ELISA.


RESULTS
The VH, VL and ScFv DNAs were about 340 bp, 320 bp and 750 bp respectively. Twenty-four MG7-positive clones were selected from 60 enriched phage clones, among which 5 displayed beta or gamma type anti-Id ScFv.


CONCLUSIONS
The anti-Id ScFv to MG7 McAb can be successfully selected by recombinant phage antibody technique, which paves a way for the study of prevention and cure of gastric carcinoma by using anti-Id ScFv.
Fengtian
He
H
Department of Biochemistry and Molecular Biology, Third Military Medical University, Chongqing 400038. hefengtian@.163.net
Yongzhan
Nie
N
Baojun
Chen
C
Taidong
Qiao
Q
Zheyi
Han
H
Daiming
Fan
F
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis* / Q000235:genetics; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D001435:Bacteriophages / Q000235:genetics; D003001:Cloning, Molecular; D007128:Immunoglobulin Fragments / Q000096:biosynthesis* / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000235:genetics; D013274:Stomach Neoplasms / Q000276:immunology*; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D012333:RNA, Messenger; D019444:Vaccines, DNA; C055966:immunoglobulin Fv