Cat. No.
MABL-3757
Application
deplete, ELISA, IF, IHC
Isotype
Engineer antibody
Species Reactivity
Human
Clone No.
huA33
From
Recombinant Antibody
Specificity
hA33 binds specifically to the ectodomain of A33 cell-surface differentation antigen. The antigen is a single-pass type-1 membrane glyoprotein of the immunoglobulin superfamily and, while not present in most normal and tumor cell type, it is expressed on the vast majority (95%) of both primary and metastatic colon cancer cells. The protein is involved in cell-cell recognition and signaling.
Alternative Names
hA33; A33; GPA33; glycoprotein A33; cell surface A33 antigen
UniProt
Q99795
Immunogen
hA33 was generated by humanization of mouse A33 IgG2a-κ by CDR-grafting, and expressed in NSO cells. The mouse A33 antibody was prepared by immunizing BALB/c mice with AsPC-1 pancreatic adenocarcinoma cell line SP2/0 myeloma cells.
Application Notes
The binding specificity and affinity of the humanized antibody has been shown to be equal to that of the orginal mouse antibody (1.3 nM), as is the uptake of 90Y-labelled antibody by human coloractal xenografts in nude mice. The circulating half-life of huA33 is also greater than that of the mouse antibody. Antigen-binding assays have been conducted by ELISA using Colo205 and SWI222 A33 antigen- expressing cells. Biodistribution assays have also been performed using hA33-12N4 conjugate in nude mice bearing subcutaneous SWI222 tumour xenografts. This antibody can be used as a biomarker for colorectal carcinoma.TFM (trivalent Fab fragment - constructed using trimaleimide cross-linkers) was shown to have a greater binding avidity for the target compared to huA33 with faster blood clearance shown in cynomolgus monkeys and guinea pigs.
Antibody First Published
King et al. Preparation and preclinical evaluation of humanised A33 immunoconjugates for radioimmunotherapy. Br J Cancer. 1995 Dec;72(6):1364-72. PMID:8519646
Note on publication
Describes the construction of humanized A33 antibody to combat rapid clearance of the antibody as a result of the human anti-mouse antibody (HAMA) response. This antibody was compared with that of the original mouse antibody and its suitibility for radioimmunotherapy of colorectal carcinoma was determined.
Size
100 μg Purified antibody.
Concentration
1 mg/ml.
Purification
Protein A affinity purified
Buffer
PBS with 0.02% Proclin 300.
Storage Recommendation
Store at 4⁰C for up to 3 months. For longer storage, aliquot and store at - 20⁰C.
