[Study on binding characteristics of 125I-labeled McAb LC-1 to lung adenocarcinoma cells in vitro and in vivo].
McAb LC-1 was derived from fusion of myeloma cells and murine spleen cells immunized with human lung adenocarcinoma SPC-A-1 cells. The immunoglobulin isotype of LC-1 belonged to IgM. LC-1 was direct against the common epitope of lung cancer. It not only reacted with small cell lung cancer but also with non small cell lung cancer. LC-1 was purified from ascitic fluid by euglobulin precipitation and Sephadex G-200 filtration chromatography, and was iodinated with Iodogen, the specific reactivity of 125I-labeled LC-1 was determined by comparing standard curve with self-displacement curve. The immunoreactive fraction of 125I-LC-1 was determined by its binding to excess of antigen. The RIA data were plotted in Scatchard-form as binding of SPC-A-1 cells to LC-1. The binding constant of LC-1 binding to SPC-A-1 was 4.8 x 10(8) M-1. The LC-1 binding sites on SPC-A-1 were 7.2 x 10(4) per cell. The RIA inhibition test showed that LC-1 and LAC-122 (another IgM isotype McAb reacted only with non small cell lung cancer) had no cross-reactivity. The treatment of SPC-A-1 cells by proteinase and sodium periodate inhibited LC-1 binding to these treated target cells by 39% and 66% respectively. These results suggested that the biochemical nature of antigen recognized by LC-1 was glycoprotein.(ABSTRACT TRUNCATED AT 250 WORDS)
Li
M
M
Shanghai Institute of Cell Biology, Academia Sinica.
Lian
B J
BJ
Ge
X R
XR
D000230:Adenocarcinoma / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D000951:Antigens, Neoplasm / Q000378:metabolism; D000954:Antigens, Surface / Q000378:metabolism; D001667:Binding, Competitive; D006801:Humans; D015592:Immunoradiometric Assay; D008175:Lung Neoplasms / Q000276:immunology*; D051379:Mice; D008819:Mice, Nude; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface