Recombinant expression of the β-subunit of HLA-DR10 for the selection of novel lymphoma targeting molecules

Huguette Albrecht, Monique Cosman, Maria Ngu-Schwemlein, Michele Corzett, Kena W. Curran, Cheryl Dolan, Xiangming Fang, Sally J. DeNardo, Gerald L Denardo, Rod Balhorn

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2 Scopus citations

Abstract

Selective high-affinity ligands (SHALs) were selected as substitutes for monoclonal antibodies (mAbs) to deliver radioisotopes to malignant tumors. Because a SHAL (5 KD) is considerably smaller in comparison to an antibody (150 KD), a significant therapeutic index (TI) enhancement for radioimmunotherapy (RIT) is anticipated. The antibody-antigen (Ab-Ag) model system chosen for the development of SHALs consists of Lym-1, a MAb with proven selectivity in non-Hodgkin's lymphoma (NHL) patients and its well-characterized Ag, the β subunit of HLA DR10. Whereas Lym-1 is readily available, the β subunit of HLA-DR10 is not. Native, heterodimeric (α and β subunits) HLA-DR10 can be purified from Raji cells, which are known to overexpress this Ag. Inconsistent homogeneity between preparations of HLA-DR10 solubilized in the presence of detergents prompted us to express a recombinant form of the β subunit of HLA-DR10 in Escherichia coli. Negligible production yields (≤50 μg/L) were achieved by the expression of the full-length protein in a soluble form. By contrast, yields of 240 mg/L were obtained by expressing only the extracellular domain (ED) of the β subunit of HLA-DR10 in an insoluble form (inclusion bodies). The recovery yield of refolded protein was 75%. Circular dichroism (CD) and Lym-1 binding studies indicated that the recombinant ED of the β subunit of HLA-DR10 was properly folded. Therefore, this recombinant protein can be used as a surrogate for native heterodimeric HLA DR10 for the in vitro selection of SHALs and related targeting molecules.

Original languageEnglish (US)
Pages (from-to)531-542
Number of pages12
JournalCancer Biotherapy and Radiopharmaceuticals
Volume22
Issue number4
DOIs
StatePublished - Aug 2007

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Keywords

  • Antibody
  • HLA-DR
  • Lymphoma
  • Radioimmunotherapy
  • Radioisotope

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Pharmacology
  • Cancer Research

Cite this

Albrecht, H., Cosman, M., Ngu-Schwemlein, M., Corzett, M., Curran, K. W., Dolan, C., Fang, X., DeNardo, S. J., Denardo, G. L., & Balhorn, R. (2007). Recombinant expression of the β-subunit of HLA-DR10 for the selection of novel lymphoma targeting molecules. Cancer Biotherapy and Radiopharmaceuticals, 22(4), 531-542. https://doi.org/10.1089/cbr.2007.375