Tumor liberated protein from lung cancer and perspectives for immunotherapy

This review addresses peptide regions of human tumor liberated protein (TLP) complexes with antigenic activity. The review also deals with antibodies reacting with such proteins, to be used for diagnostic and clinical purposes. We identified peptide sequences of the TLP 100 kDa protein. Lung cancer cells were found positive with an immuno-histochemical test, by peroxidase-anti-peroxidase, using a specific antiserum. This test turned out negative in the presence of the synthesized peptide (blocking test). Several tumors were used to obtain antigens by various purification procedures (cell homogenization, ultracentrifugation at 100,000g, gel filtration and chromatography, preparative and analytical isoelectric focusing, IEF). The molecular weight on SDS-PAGE of an immunogenic peak detected on IEF was determined to be a value of 214,000 Da, with monomers of 54,000 Da. In vivo TLP yields delayed hypersensitivity reactions in both autologous and homologous hosts, and does not seem to have any nonspecific mytogenic activity, but does have mytogenic-specific activity since lymphocyte blastogenesis (TLP-induced in pre-sensitized patients), in the case of intradermal inoculation, could mean its ability to sensitize a lymphocytic clone.