Serological immune response to cancer testis antigens in patients with pancreatic cancer

Abstract

Serological screening approaches have allowed for the identification of a large number of potentially relevant tumor antigens in cancer patients. Within this group, cancer testis antigens represent promising targets for cancer immunotherapy, since they are widely expressed in a variety of human cancer entities. In pancreatic cancer, however, there are only few data available about the expression pattern and serological response to cancer testis antigens and other serological-defined tumor antigens. Therefore, we investigated the IgG antibody response against 11 cancer testis antigens (SCP-1, GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5) recombinantly expressed on yeast surface (RAYS) in patients with pancreatic cancer (n 5 96), chronic pancreatitis (n 5 18) and healthy donors (n 5 48). We found in 14% of all patients antibody responses to SCP-1, but not to other cancer testis antigens (GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5). Antibody response correlated with the expression of SCP-1 in the primary tumor of the respective patient as shown by RT-PCR, immunohistochemistry and Western blot. In contrast, no serological response to cancer testis antigens was observed in healthy donors. The humoral immune response against SCP-1 was associated with the size of tumor, but not with other clinico-pathological parameters such as histology, stage, presence of lymph node metastases, grading, age, gender or gemcitabine treatment. In conclusion, antibody response to cancer testis antigen SCP-1 is found in a proportion of pancreatic carcinoma patients. These results indicate that identification of additional tumor antigens by serological screening of tumor cDNA expression libraries by RAYS is a promising goal in pancreatic cancer. ' 2006 Wiley-Liss, Inc.

Seromic profiling of ovarian and pancreatic cancer

“…1). As expected from previous studies, NY-ESO-1 and LAGE-1 were recognized with the highest frequency by ovarian cancer sera (17% and 19%, respectively), but not by pancreatic cancer sera or by healthy donor sera, echoing differences in CT antigen expression in these two tumor types, ovarian cancer being CT antigen-rich (22-24) whereas pancreatic cancer was previously shown to be CT antigen-poor (25,26). Accordingly, serum reactivity to MAGE antigens, SSX2, CT7, or CT10 was also found primarily in ovarian cancer samples (Fig.…”

Recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant induces broad antibody responses in humans, a RAYS-based analysis

“…When the ratio of the mean fluorescence intensity (g-mean) of CT-antigen expressing yeast versus empty vector expressing yeast was >2, a serum was considered positive. This cut-off point was successfully established in our previous studies (6,9,10) as well as by other groups (12). A positive serum reactivity is shown in Fig.…”

“…The amplified codogen regions of the CT-antigens NY-ESO-1, NY-ESO-1 (trunc. ), LAGE-1A, LAGE-1B, SSX-2, SSX-4, CT-7 and CT-10 and the respective NY-ESO-1 fragments were cloned into the multiple cloning site of the pYD1 plasmid (Invitrogen, Leiden, The Netherlands) as described previously (6,10). Plasmids were introduced into Saccharomyces cerevisiae EBY100, using a commercially available transformation kit (EasyComp, Invitrogen), according to the manufacturer's recommendations.…”

“…Verification of yeast surface-expressed protein was done by standard Western blot analysis as described previously (10). Briefly, proteins were cleaved under reducing conditions (100 mM mercaptoethanol, 1 h, 20˚C) and concentrated by chloroform/methanol precipitation.…”

“…As a consequence, we established a eukaryotic cDNA expression system in yeast (RAYS) (6) with the advantage that recombinant proteins can be expressed on the yeast surface as part of the cell wall in a more naturally folded and partially glycosylated manner (7,8). We and others successfully used this system for serological tumor antigen characterization (6,(9)(10)(11)(12).…”