Purification of tumor-associated embryonic substance from mouse ascites tumor cells: its cross-reactivity with human CEA

1. Tumor-associated embryonic substance (TAES), which was detected on MM2 cells by cell agglutination method using MM2-regressor mouse serum, was purified from MM2 cells to gel electrophoretically pure substance. The recovery was 0.9 mg (protein) from 100 g (wet weight) cells. TAES is a glycoprotein of 21S. 2. TAES inhibited cross-agglutination of MM2 cells by various syngeneic regressor serum, tumor-bearer serum or pregnant mouse serum. 3. From agglutination inhibition experiment, it was concluded that TAES and human CEA have a common binding site for the agglutination factor. 4. The binding site contains saccharide moiety of these molecules with N-acetyl glucosamine at the non-reducing terminus. 5. Although TAES and CEA cross-reacted in agglutination-inhibition experiments, their antigenicity to xenogeneic animal did not show cross-reactivity.

Growth stage-dependent sialylation of tumor-associated embryonic substances on mouse ascites tumor cells

It has been reported that sera from tumor-regressor mice contain a class of sugar-binding proteins which specifically bind to the tumor cell surface antigens when terminal sugar residues are deleted from the glycoprotein molecules of the antigens and thus agglutinate free-cell type tumor cells in vitro. Using such agglutination of tumor cells with appropriate regressor sera, sialylation of cross-reacting tumor-associated embryonic substances on the surface of various ascites tumor cells of mice was studied. The result showed that sialylation of tumor-associated embryonic substances in all cases took place at specific stages of cell growth after transplantation of the cells, while sialylation of other cellular components in general occurred throughout the growth stages. Marked differences was observed between timing of sialylation of tumor-associated embryonic substances of hyperdiploid tumor cells and that of hypotetraploid tumor cells.

Agglutination of murine tumor cells by sera from patients with autoimmune diseases

A method of <i>in vitro</i> agglutination of murine ascitic tumor cells which had been used to detect and to semiquantitate components with saccharide-binding properties in sera from cancer patients was applied on sera from patients with various autoimmune diseases. Sera from 36 of 56 patients with such diseases, after removal of their cytocidal activity on the murine tumor cells by absorption with liver tissue from normal adult mice, agglutinated the tumor cells which had been harvested while they were rapidly proliferating <i>in vivo</i>. The agglutination activity was absorbed completely by embryonic tissue of mouse. The agglutination was inhibited by perchloric acid extract of the tumor cells and also by monosaccharides such as galactose or <i>N</i>-acetyl-<i>D</i>-glucosamine. The inhibition activity of the perchloric acid extract was affected by treatment with glycosidases but not trypsinization. These results showed that carbohydrate moieties of murine tumor cell surface components were involved in the agglutination and therefore that there was an increase of components with saccharide-binding properties in the sera of patients with autoimmune diseases compared to the sera of normal controls. This increase in turn suggested by analogy to tumor-bearing animals that a sort of humoral reaction took place in the patients against changes related to autoimmune diseases of carbohydrate moieties of the cell surface substances.

[Investigations on retinopathia pigmentosa. Statistical analysis of perimetry results (author's transl)]

Kinetic perimetry was carried out using the Goldmann perimeter in 201 patients with primary pigmentary retinal dystrophy, 156 autosomal recessive and 45 autosomal dominant cases. "The advanced stage" of the isopter deterioration was defined as the isopter area with the test object I-4 being 1 cm2 or less on the chart of Goldmann. The frequency of "the advanced stage" cases in creased with age in both hereditary forms, but it was higher in the recessive than in the dominant form throughout all age groups. The frequency-age relationship was exponential as is found in various aging phenomena. Fifty per cent of the patients were in "the advanced stage" at the age of 30 years in the recessive and at the age of 56 years in the dominent form.

Cell line-specific cell surface components of hypotetraploid ascites mammary carcinoma cells inducing humoral reactions in the syngeneic host

Cell-line specific cell surface components were demonstrated on cells of various hypotetraploid ascites cell lines, but not on hyperdiploid cells derived from a mammary carcinoma induced by mammary tumor virus (MTV) in syngeneic C3H/He mice. These substances caused cell-line-specific transplantation antigenicity and were identified, together with MTV-associated substances and tumor-associatied embryonic materials, as being the binding sites for tumor cell agglutinating factors found in sera from tumor-bearing and regressor animals. Particles containing the cell line-specific substances were released from these cells by hypnotic treatment. They could be purified as a single peak in a sucrose density gradient. They were, however, not dissociated from the MTV-associated substances. Absorption studies of agglutination activity were extensively used for demonstration of specificity.

Humoral reactions in syngeneic hosts against tumor cell surface incomplete saccharide moieties

Components on the surface of MM2 ascites mammary carcinoma cells induce agglutination factors in the serum of syngeneic host C3H/He mice, and bind the factors in vitro. These components have been classified into three groups: MM2-specific substances, mammary tumor virus (MTV)-associated substances and tumor-associated embryonic materials. The substances contained saccharide moieties and their terminal sugar residues were essential for the binding of the serum factors. These terminal saccharides were exposed during cell proliferation,but masked in stationary cells, at least partly, due to elongation of the saccahride moieits. The terminal structures of these polysaccharide moities of growing and stationary cells were studied by semiquantitative tumor cell agglutination using the agglutinating activities against MM2 cells of MM2-regressor serum and of FMA/R- and Ehrlich-regressor sera which had partial cross-agglutination activities. Agglutination by phytohemagglutinins, inhibition of the agglutination by saccharides or with isolated cell surface components and treatment of the cells with glycosidases were also used for this purpose.

The induction of immunity against tumor cell transplantation with a complex of tumor cell surface substance and a serum component found in the tumor-regressor animals

Immunity against transplantation of MM2 cells, an ascites cell line of mouse mammary carcinoma, was induced in syngeneic C3H/He mice by intraperitoneal injection of a complex formed between a MM2-specific surface component isolated from the cells and a serum factor found in the serum from MM2-regressor and MM2-bearing mice. The induced immunity was transferable to other mice with the spleen cells or with the serum from the immunized animals. This cell surface component was not immunogenic by itself. A new immunogenicity was induced in the protein moiety of this substance when the serum factor was bound to the polysaccharide-containing part of the molecule. On the basis of these results, a biphasic mechanism for the induction of the humoral immunity against tumor antigens was proposed. The first phase takes place in tumor-bearing animals and gives rise to the serum factor. The second phase, which is blocked in tumor-bearing animals, consists of the induction of the humoral immunity by the complex in tumor-free animals.