Monoclonal antibodies against CA125-bearing antigenic molecule fragments; reactivity with mucinous ovarian tumours and lung cancers

Relation between Ovarian Carcinoma-Associated Antigens in Tumor Tissue and Detached Cyst Fluid Cells of Patients with Ovarian Neoplasms

Aims

The expression and potential diagnostic value of ovarian carcinoma-associated antigens were estimated in different types of epithelial ovarian neoplasms. The comparison of antigenic expression was performed on solid tumor tissues and loose cyst fluid cells in individual cases of malignant and benign ovarian neoplasms.

Methods

All studies were performed using monoclonal antibodies (mAbs) against ovarian carcinoma-associated antigens (OC125, OV-TL3, OV632, 10B, 8C) by 3-step peroxidase-antiperoxidase test.

Results

All ovarian carcinoma-associated antigens were detected in most serous and endometrioid carcinomas. In mucinous carcinomas as well as in benign ovarian neoplasms these antigens were present only in some cases. Significant inter- and intratumoral immunological heterogeneity was evident; however, the antigens detectable in tissue sections were also found in detached cyst fluid cells.

Conclusions

Our results show that mAb show OV-TL3 is the best marker for endometrioid carcinomas and confirmed that mAbs OV632, OC125 and OV-TL3 could be good complementary markers for differentiating malignant and benign lesions in the ovary. The percentage content of all ovarian carcinoma-associated antigens in solid tumors and respective cyst fluid cells was comparable.

Cellular differentiation status of epithelial polyps of the colorectum: the gastric foveolar cell-type in hyperplastic polyps

AIMS

The 'metaplastic' polyp of the colorectum, a synonym for the hyperplastic polyp, was named based only on features of the crypt epithelium. It is considered non-neoplastic, but the precise cellular differentiation status remains to be proven.

METHODS AND RESULTS

Forty-eight hyperplastic polyps, 12 serrated adenomas, 45 tubular adenomas and five juvenile polyps were studied for their phenotypic expression using gastric (foveolar or pyloric gland cell), small intestinal (goblet cell), and colonic (goblet cell) cellular markers by immunohistochemical and mucin histochemical techniques. Gastric foveolar cell-type differentiation was significantly expressed in hyperplastic polyps, while colonic differentiation was also consistently preserved. Neither gastric pyloric-type nor small intestinal differentiation was observed. The same cell differentiation status as hyperplastic polyps was observed in serrated adenomas but not in tubular adenomas or juvenile polyps.

CONCLUSIONS

A large proportion of hyperplastic polyps are composed of hybrid epithelium, with bidirectional differentiation to both gastric foveolar and colonic epithelial cells in the same crypt. Therefore hyperplastic polyps might be interpreted as the outcome of abnormal cell differentiation of stem cells. The same phenotypic expression suggests that hyperplastic polyps and serrated adenomas share the same cell lineage.

Gastric and intestinal mixed and solely intestinal types of intestinal metaplasia in the human stomach

To generate a novel understanding of intestinal metaplasia (IM) on the basis of cellular differentiation status, a total of 132 gastric surgical specimens were studied using gastric and small intestinal cell markers by mucin histochemical and immunohistochemical techniques. The cases were divided into two types: (i) gastric and intestinal (GI) mixed type; and (ii) solely intestinal (I) type, with the reference to the presence of gastric and/or intestinal cell markers. The GI mixed type was subdivided into six subtypes: (I) a subtype consisting of surface mucous (Su), pyloric gland (Py), intestinal absorptive (Ab), and goblet (Go) cells, but lacking Paneth (Pa) cells, GI(Pa-); (ii) a GI(Pa-) subtype without Py cells, GI(Py-, Pa-); (iii) a GI(Pa-) subtype without Su cells, GI(Su-, Pa-); (iv) a GI(Su-, Pa-) subtype with Pa cells, GI(Su-, Pa+); (v) a GI(Pa-) subtype with Pa cells, GI(Pa+); and (vi) a GI(Pa+) subtype without Py cells, GI(Py-, Pa+). The I type was subdivided into: (i) a subtype consisting of cells with Ab and Go cells, I(Pa-); and (ii) a I(Pa-) subtype with Paneth cells, I(Pa+). The GI mixed subtypes, except for the GI(Py-, Pa-) and GI(Py-, Pa+), were characterized by intestinalized gastric pits connected with underlying pyloric glands. Immunohistochemical staining of proliferating cell nuclear antigen (PCNA) revealed a common proliferative cell zone between the two. The GI mixed type, especially the GI(Pa-) subtype, predominated in the pyloric mucosa, while the I type was most frequent in the fundic region, suggesting that the pathogenesis of IM differs between these two locations. The results of the study confirm that IM is an abnormal and unstable differentiation status between the stomach and small intestine.

Cellular differentiation and development of pyloric mucosal metaplasia in the human gall-bladder

The development of pyloric mucosal metaplasia (PMM) with regard to cellular differentiation in the human gallbladder was studied by mucin staining (paradoxical concanavalin A (Con A), galactose oxidase-Schiff (GOS) and alcian blue (pH 2.5) PAS (AB-PAS) and immunohistochemistry (pepsinogen II (PgII) and SH-9, and proliferating cell nuclear antigen (PCNA). PMM was divided into three stages of development by three-dimensional (3D) computer graphic reconstruction analysis. In the early stage, a transitional zone of PCNA positive cells was observed between areas of SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells in flat monolayered epithelium. In the middle stage, shallow pits became apparent as areas enlarged, with these becoming deeper in the advanced stage, whereby SH-9 and/or GOS reactive cells and class III and/or Pg II positive cells were observed at the upper and lower portion of the pits, respectively, with PCNA-positive cells forming a narrow zone between the two cell populations. Consequently, the structure of PMM gradually resembles that of the normal gastric pyloric mucosa.

A monoclonal antiidiotypic antibody ACA 125 mimicking the tumor-associated antigen CA 125 for immunotherapy of ovarian cancer

A new concept of oncological immunotherapy comprises the attempt to trigger the immune system of the host into a response against tumor cells. Antiidiotypic antibodies bearing the internal image of an antigen expressed on the surface of the tumor seem to be most suited for this purpose. We have generated a murine antiidiotypic antibody (ACA 125) functionally imitating the tumor-associated antigen CA 125, which can be detected in about 80% of ovarian carcinomas. The hybridoma cell was adapted to serum-free medium and antibody was produced in a hollow fiber cell culture system (Technomouse). ACA 125 (Ab2) shows high affinity for the paratope of Ab1 (affinity constant: 2.3 x 10(9) liters/mol) and binding of Ab2 to Ab1 is completely inhibited by the nominal antigen. Application of F(ab')2 fragments of ACA 125 to rats lead to an anti-CA 125 immunity by production of IgG and IgM antiantiidiotypic antibodies (Ab3) that bind to both ACA 125 and CA 125. Furthermore the induction of a non-MHC-restricted cell-mediated cytotoxicity for human ovarian adenocarcinoma cell line NIH-OVCAR3 (expressing CA 125 on its surface) could be proved; additionally complement-dependent cytotoxicity (CDC) as well as an antibody-dependent cellular cytotoxicity (ADCC) was observed. Thus, monoclonal antiidiotypic antibody ACA 125 fulfills recent criteria for an antibody, which might be successful in immunotherapy using the anti-idiotypic network approach.

Expression of sialosyl-Tn in intestinal type cancer cells of human gastric cancers

A sample of 219 primary stomach cancers, 143 advanced cancers and 76 early cancers were examined for mucin histochemical staining (the paradoxical concanavalin A method, the galactose oxidase-Schiff [GOS] reaction, and the sialidase-GOS reaction) and immunohistochemical reactivity (pepsinogen [Pg] I, Pg II, SH-9 and TKH-2). Gastric cancer cells were clearly classified according to mucin histochemistry into a gastric type, including mucus neck cell, pyloric gland cell and surface mucus cell types, and an intestinal type, including goblet-cell, and intestinal absorptive cell types. TKH-2 monoclonal antibody, which recognizes the mucin-associated sialosyl-Tn antigen, reacted with the mucin of goblet cells in both the normal small intestine and in the intestinal metaplasia of the stomach. Sixty-five of 106 (61%) differentiated adenocarcinomas and 76 of 113 (67%) undifferentiated adenocarcinomas had over 10% of their cancer cells positive for TKH-2. The TKH-2-positive cancers were primarily classified as a goblet-cell type by mucin-histochemical staining and the other immunohistochemical staining methods. Therefore, it is concluded that sialosyl-Tn is an excellent marker of small intestinal mucins and is indicative of a small intestinal type of differentiation in two-thirds of gastric cancers.

Markers of surface mucous cell type human gastric cancer cells: galactose oxidase-Schiff reactive mucins, monoclonal antibody SH-9 reactive mucins and cathepsin E

Cellular differentiation of gastric cancer cells allows the classification of cell type into surface mucous cell, pyloric gland cell, intestinal absorptive cell and goblet cell types by mucin histochemistry and pepsinogen (Pg) immunohistochemistry. Surface mucous cell differentiation of gastric cancers of each histologic type has previously been detected by the galactose oxidase-Schiff (GOS) reaction although this is not always positive in all cases. Mucus granules of surface mucous cells of normal gastric mucosa show an intense reactivity for SH-9 (monoclonal antibody against CA125-bearing antigenic molecule fragments). Cathepsin E is also expressed in the cytoplasm of surface mucous cells, weakly in absorptive cells of duodenal villi and occasionally in pyloric gland cells. Expression of SH-9 reactive mucin and of cathepsin E were therefore investigated as possible additional markers to distinguish between the gastric cancer cell type in 203 primary stomach cancers. SH-9 reactive mucin was found selectively in GOS positive cancer cells of surface mucous cell type and/or cancer cells unclassified by mucin histochemistry. These latter cells were therefore classified into the surface mucous cell category. Cathepsin E was found mainly in cancer cells of the GOS positive surface mucous cell type and occasionally, in intestinal absorptive and pyloric gland cell types. Galactose oxidase-Schiff, SH-9 and cathepsin E reactive or positive cancer cells were found in 145 (71.4%), 151 (74.4%) and 144 (70.9%), respectively, of the 203 primary stomach cancers investigated.