Sheep bronchoalveolar carcinoma: tissue associated protein complex (TAPC) in normal lung tissue and in the tumor...

Sheep lungs experimentally and naturally affected by bronchoalveolar carcinoma were washed out exhaustively of soluble components by phosphate-buffered saline, pH 7.4 (PBS), followed by glycine buffer, pH 2.8 (GB), and then again by 1M KCl followed by PBS. The tissue matrix (TM) of the tumor-free region and the tumor-affected tissue were analysed separately by sodium dodecyl sulfate (SDS) polyacrylamide electrophoresis. Normal lung tissues obtained from normal sheep served as controls. Several protein fractions and fragments, identified in both the normal and the tumorous lung, have the molecular weight (MW) of 130,000-228,000, as compared with the major soluble tissue associated protein having MW of 70,000. Coomassie blue staining used in the SDS polyacrylamide system and alkaline phosphatase immunoreaction used in the Enzyme Linked Immunosorbant Assay (ELISA) showed tenfold increased concentration of the TAPC in the TM of the tumor tissue and in the blood of tumor-affected animals, respectively. Total concentration of the TAPC in the serum of tumor-affected animals was higher than in the normal. Immunofluorescent antibody test (IAT) detected the TAPC in the cytoplasm of tumor as well as in normal lung cells, and the study suggested that the TAPC reaches the peripheral blood during tissue destruction occurring at the tumor site, as observed by light and electron microscopy (LM and EM). The concentration of each of the TAPC fractions was higher in the tumor-affected sheep lung as compared with normal sheep lung. Antibodies prepared against the TAPC fractions were toxic to sheep lung cells in tissue culture. Tumor cells were more susceptible.