Antibody engineering for cancer therapy

Antibodies targeting various tumor-associated antigens have been developed successfully to treat cancer. In this Thesis, novel antibodies and antibody-conjugate against two tumor antigens, AF-20 antigen and human aspartyl (asparaginyl) [beta]- hydroxylase (HAAH), were developed. Previously, these two tumor antigens have been shown to be present on a variety of tumor cells, while they have minimal expression on normal tissues, rendering them excellent targets for antibody therapy. For the AF-20 work, the variable region (V) gene of a previously isolated mouse monoclonal antibody (mAb) AF-20 was cloned from hybridoma mRNA and used to construct an AF-20 single-chain Fv (scFv). The AF-20 scFv was shown to bind specifically to the same epitope as mAb AF-20 with a binding affinity of 4nM. The AF- 20 scFv was also internalized into tumor cells in a manner identical to that of the original mAb AF-20. The scFv was later employed for cellular internalization of virus-sized fluorescent quantum dots. In addition, to demonstrate the versatility of this antibody, an immunotoxin composed of AF-20 scFv fused to the highly cytotoxic recombinant toxin gelonin was constructed, and its in-vitro efficacy against three different tumor cell lines were evaluated. The IC50 of the AF-20 scFv-gelonin fusion was consistently one to two logs lower than the IC50 of free gelonin on FOCUS (liver), L3.6pl (pancreas) and PC3 (prostate) cells, further demonstrating the capability of the AF-20 scFv as a targeting module. Therefore, this AF-20 scFv is a potential internalization vector for toxins, enzymes, radionuclides and virus for targeted therapy of AF-20-antigen expressing tumor cells.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Yeung, Yik Andy

Advisor dc:contributor.advisor

• K. Dane Wittrup.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32325

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32325