A human tumour-associated membrane antigen from squamous-cell carcinoma of the lung

Abstract

Summary.-Primary human squamous-cell lung tumours were disrupted using mechanical high-speed homogenization. Crude membranes were isolated by differential centrifugation at low speeds followed by 100,000 g centrifugation. Such membrane preparations were extracted with Triton-X-100 and passed over a DEAE cellulose column; the DEAE unbound fraction and the bound fraction eluted with 0-4M NaCl were used to immunize rabbits. We present here only data on a single lung-tumour-associated membrane antigen (TAMA) found in the unbound DEAE cellulose column eluates. This new Triton-X-100 extractable antigen is termed lung TAMA-1.A further purification of the antigen was achieved using two methods. The first used G-200 molecular-seive chromatography and this revealed lung TAMA-1 to have a mol. wt of 200,000. A second method used sucrose density-gradient isoelectric focusing, and the antigen had an isoelectric point of -3 0.Several important properties of the lung TAMA-1 were determined. The antigen has a cathodal gamma-type electrophoretic mobility at pH 7-6. The antigen was not detected in any normal human adult or foetal tissue extracts tested. It did not crossreact immunochemically with CEA, AFP or p2 microglobulin. Lung TAMA-1 was detected in 80% of lung tumour Triton-X-100 extracts tested by counterimmunoelectrophoresis (CIEP) but was undetectable in breast or colon carcinoma extracts.Low frequency sonication did not deleteriously affect lung TAMA-1, but, 3M KCI eliminated its immunologic reactivity in CIEP. Finally, preliminary data were obtained using immunohistochemistry to localize in vivo lung TAMA-1 production.

Biologic Markers in Lung Cancer

“…36 Veltri has described a cell membrane antigen that is identifiable in 80 percent of all lung cancers and is not found in normal lung tissue or other types of cancer. 119 Ibrahim has developed an antiserum to human lung cancer tissue which reacts solely to the serum of lung cancer patients. 57 Much work remains to verify these observations in clinical trials, but the opportunities are increasing in the search to find a lung-cancer-specific marker that will have practical application in the diagnosis, screening, and treatment of pulmonary malignancies.…”

Antibody response to a solubilized tumor-associated membrane antigen (TAMA) from the murine lewis lung tumor

“…The immunization protocol has been described previously [29]. Two rabbits were primed with Freund's incomplete adjuvant.…”