Generation, characterization, and in vivo studies of humanized anticarcinoma antibody CC49

Hybridoma. 1995 Oct;14(5):461-73. doi: 10.1089/hyb.1995.14.461.


Monoclonal antibody (MAb) CC49 reacts with tumor-associated glycoprotein (TAG)-72, a human pancarcinoma antigen. In clinical trials, radiolabeled CC49 has shown excellent tumor localization; however, many of the patients receiving MAb CC49 develop a human antimouse antibody response. In an attempt to prevent this antiimmunoglobulin response, we have developed a humanized CC49 (HuCC49) by grafting the MAb CC49 hypervariable regions onto the variable light (VL) and variable heavy (VH) frameworks of the human MAbs LEN and 21/28' CL, respectively, while retaining those murine framework residues that may be required for the integrity of the antigen combining-site structure. The HuCC49 MAb was compared with native murine CC49 (nCC49) and chimeric CC49 (cCC49), using a variety of assays. SDS-PAGE analysis under nonreducing conditions showed that the HuCC49 MAb has virtually identical mobility to that of cCC49. Under reducing conditions, the HuCC49 yielded two bands of approximately 25-28 and approximately 50-55 kDa, characteristic of heavy and light immunoglobulin chains. In competition radioimmunoassays, HuCC49 completely inhibited the binding of 125I-labeled nCC49 to TAG-72, although 23- to 30-fold more HuCC49 was required to achieve a level of competition similar to those of cCC49 and nCC49. The relative affinity of HuCC49 was 2- to 3-fold less than those of the cCC49 and nCC49 MAbs, respectively. The plasma clearance in mice of HuCC49 was virtually identical to that of cCC49. Biodistribution studies demonstrated equivalent tumor-targeting of HuCC49 and cCC49 to human colon carcinoma xenografts. These studies thus suggest that HuCC49 and genetically modified molecules, such as sFv and domain-deleted immunoglobulins developed by using the HuCC49 variable region as a cassette, may be potentially useful in both diagnostic and therapeutic clinical trials in patients with TAG-72-positive tumors.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / biosynthesis*
  • Antibodies, Monoclonal / chemistry*
  • Antibodies, Monoclonal / pharmacokinetics
  • Antibodies, Neoplasm / biosynthesis*
  • Antibodies, Neoplasm / chemistry*
  • Antibodies, Neoplasm / genetics
  • Antigens, Neoplasm / immunology
  • Base Sequence
  • Binding, Competitive / immunology
  • Female
  • Genes, Immunoglobulin
  • Genetic Vectors
  • Glycoproteins / immunology
  • Humans
  • Immunoglobulin Heavy Chains / genetics
  • Immunoglobulin Light Chains / genetics
  • Immunoglobulin Variable Region / genetics
  • Mice
  • Mice, Nude
  • Molecular Sequence Data
  • Radioimmunoassay
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / pharmacokinetics
  • Tumor Cells, Cultured


  • Antibodies, Monoclonal
  • Antibodies, Neoplasm
  • Antigens, Neoplasm
  • Glycoproteins
  • Immunoglobulin Heavy Chains
  • Immunoglobulin Light Chains
  • Immunoglobulin Variable Region
  • Recombinant Fusion Proteins
  • tumor-associated antigen 72

Associated data

  • GENBANK/S81415
  • GENBANK/S81417