Radioimmunometric demonstration of immunoglobulin G on cancer cells derived from malignant pleural effusions.
Well-preserved viable cancer cells, lymphocytes and mesothelial cells were prepared from various human malignant and non-malignant pleural effusions by a Ficoll-Hypaque discontinuous gradient. Using 125I-labelled protein A from Staphylococcus aureus as tracer, IgG was found on all cancer cells and also on apparently non-malignant mesothelial cells. Loss of cell surface IgG by overnight incubation, and fluctuation of surface IgG levels in the same patient occurred with cancer cells as well as with mesothelial cells. The IgG in vivo coat of cancer cells reflected the IgG levels of the sera rather than those of the pleural effusions. Binding of IgG from autologous and allogeneic sera and from supernatants of acid and mild overnight elution of cancer cells and mesothelial cells did not indicate a cancer-specific uptake of IgG. Various unspecific modes of IgG uptake by cancer cells are discussed including the possibility of a non-immune mechanism. Modification and loss of antigens by metastatic cells have also been considered.
D002462:Cell Membrane / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D008858:Microscopy, Phase-Contrast; D009369:Neoplasms / Q000097:blood / Q000276:immunology* / Q000473:pathology; D010996:Pleural Effusion / Q000276:immunology* / Q000473:pathology; D011485:Protein Binding; D011863:Radioimmunoassay; D013205:Staphylococcal Protein A / Q000494:pharmacology; D013997:Time Factors
D007074:Immunoglobulin G; D013205:Staphylococcal Protein A