Humoral immune responses of lung cancer patients against tumor antigen NY-ESO-1.

The cancer-associated antigen NY-ESO-1 is expressed in a number of malignancies of different histological type. Patients with NY-ESO-1 expressing tumors have been shown to bear circulating autoantibodies against this antigen. In this study, we have assessed the NY-ESO-I autoantibody response in patients with lung cancer by a serum ELISA. Using a serum dilution of 1:400 we detected seroreactivity in 35 of 175 (20%) of patients. Incidence of autoantibodies was significantly higher in patients suffering from non small cell lung cancer (NSCLC, 23%) as compared to those with small cell lung cancer (SCLC, 9%). In the NSCLC group, NY-ESO-I antibody was significantly more frequent in patients with undifferentiated tumors (40%) as compared to patients with either adenocarcinoma or squamous cell carcinoma (15 and 29%). Our observations indicate that induction of NY-ESO-I autoantibodies depends on the histological subtype within a given tumor entity.

CrELISA: a fast and robust enzyme-linked immunosorbent assay bypassing the need for purification of recombinant protein.

A multitude of antigens has been recently identified by screening of cDNA expression libraries derived from human tumors with autologous sera. Using a phage autoantibody assay and small panels of sera derived from cancer patients or controls it has been shown that some of these antigens display cancer-associated autoantibody responses. The diagnostic and prognostic significance of these potentially cancer-related autoantibodies remains unclear until large-scale assays are developed and serological data are available for hundreds of cancer patients and controls. The major bottleneck for the development of large-scale assays are the cloning, expression and the purification of each of the respective antigens. Due to these limitations and despite the potential clinical relevance large-scale autoantibody tests are established for only a few of these tumor antigens. Here we describe an enzyme-linked immunosorbent assay, Crude lysate ELISA (CrELISA), suitable for antigens identified by expression screening based on crude lysates of antigen-expressing bacteria. This assay permits sensitive and specific autoantibody seroscreening without the need of laborious and time-consuming cloning, expression and purification of recombinant proteins. CrELISA is robust and provides a versatile high throughput procedure for the rapid evaluation of multiple antigens in large-scale serology.