Specific blastogenic response of peripheral blood lymphocytes from lung cancer patients to a fetal lung antigen

A human lung tumor fetal-associated antigen (LTFA) has been purified from lung tumor tissue by a combination of salt precipitation and ion-exchange chromatography. The purification steps were monitored by double immunodiffusion with the use of a rabbit anti-LTFA-specific antiserum. The isolated protein was tested for its blastogenic properties toward peripheral blood lymphocytes (PBL) by [3H]thymidine incorporation. PBL obtained from 25 healthy individuals, 34 patients with tumors other than lung tumors, 13 patients with lung diseases other than lung tumors, and 51 lung tumor-bearing patients were tested. Only PBL with an in vitro positive response to phytohemagglutinin were employed. Whereas PBL of lung tumor patients showed a significant blastogenic response to the purified antigen in 14 of 22 patients tested (60%), PBL of other patients were completely unreactive (P less than 0.005). The present data suggested that a specific immune response toward an LTFA was present in patients with lung cancers.