Autoradiographic evaluation of monoclonal antibodies' access to melanoma-associated antigens in melanoma xenografts.
Autoradiography of nude mice bearing human malignant melanoma xenografts was performed to characterize the distribution pattern of radioiodinated anti-melanoma monoclonal antibodies (MoAb) and fragments in macroscopic tumor nodules. Non-uniformity of radioactivity distribution was seen in all MoAb-xenograft combinations. The predominant patterns were marked deposition of radioactivity either in the periphery of nodules or in sharply delimited intra-tumoral foci. These patterns were generated by limitations in the accessibility of melanoma tissue rather than gross necrosis or heterogeneity of antigen expression. Computer-aided densitometry of autoradiograms was used to elaborate the difference of accumulation in intra-tumoral hot spots versus cold areas. It was found that increasing uniformity was achieved by increasing the dose of MoAb (i.e., intact IgG) injected, whereas a reduction in the size of MoAb (IgG greater than F(ab')2 greater than Fab) showed no such effect.
Matzku
S
S
Institute of Radiology and Pathophysiology, German Cancer Research Center, Heidelberg.
Schmid
J
J
Tilgen
W
W
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D001345:Autoradiography / Q000379:methods; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009336:Necrosis; D009368:Neoplasm Transplantation; D010446:Peptide Fragments / Q000032:analysis; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D007074:Immunoglobulin G; D010446:Peptide Fragments