Quantitative autoradiographic evaluation of the influence of protein dose on monoclonal antibody distribution in human ovarian adenocarcinoma xenografts

Farley E. Yang, Raya S. Brown, Ken F. Koral, Anaira C. Clavo, Gayle A. Jackson, Richard L. Wahl

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

We studied the effect of monoclonal antibody protein dose on the uniformity of radioiodinated antibody distribution within tumor masses using quantitative autoradiography. Groups (n = 11-13/group) of athymic nude mice with subcutaneous HTB77 human ovarian carcinoma xenografts were injected intraperitoneally with an125I-labeled anticarcinoma-associated antigen murine monoclonal antibody, 5G6.4, using a high or a low protein dose (500 μg or 5 μg). At 6 days post-injection the macroscopic and microscopic intratumoral biodistribution of radiolabeled antibody was determined. The degree of heterogeneity of the labeled antibody distribution within each tumor was quantified and expressed as the coefficient of variation (CV) of the activity levels in serial histological sections. Tumors from mice given the 500-μg protein doses had substantially lower CV values, 0.327±0.027, than did tumors from animals given 5-μg protein doses, 0.458±0.041, (P = 0.0078), indicating that the higher protein dose resulted in more homogeneous distribution of radioactivity in tumors than did the lower dose. While the percentage of the injected dose reaching the tumor was comparable between groups, injecting the higher dose of protein resulted in significantly lower tumor to non-tumor uptake ratios than those obtained for the lower protein dose. These data indicate, in this system, that to achieve more uniform intratumoral antibody (and radiation for radioimmunotherapy) delivery, a relatively high protein dose must be administered. However, to obtain this increased uniformity, a substantial drop in tumor/background uptake ratios was seen. Quantitative autoradiographic evaluation of human tumor xenografts is a useful method to assess the intratumoral distribution of antibodies.

Original languageEnglish
Pages (from-to)365-372
Number of pages8
JournalCancer Immunology Immunotherapy
Volume35
Issue number6
DOIs
StatePublished - Nov 1992

Keywords

  • Monoclonal antibody
  • Ovarian carcinoma
  • Quantitative autoradiography
  • Radiolabeled compounds

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