Isolation from patients with breast cancer of antibodies specific for antigens associated with breast cancer and other malignant diseases

Promotion of tumor invasion by cooperation of granulocytes and macrophages activated by anti-tumor antibodies

We investigated the potential role of anti-tumor antibodies and tumor antigens in the formation of immune complexes which promote matrix degradation and angiogenesis. B-cell deficient or B-cell depleted mice showed a reduction in tumor invasion and metastasis. In vitro invasion assays and in vivo models of metastasis showed that anti-sTn antibodies and sTn tumor antigens form complexes which induce granulocytes and macrophages together to mediate tumor invasion and metastasis by processes including extracellular matrix degradation and angiogenesis. These results suggest the existence of a tumor promoting role of a B-cell immune response induced by shed tumor associated antigens of solid, nonlymphoid tumors.

Structurally well-defined macrophage activating factor derived from vitamin D3-binding protein has a potent adjuvant activity for immunization

Freund's adjuvant produced severe inflammation that augments development of antibodies. Thus, mixed administration of antigens with adjuvant was not required as long as inflammation was induced in the hosts. Since macrophage activation for phagocytosis and antigen processing is the first step of antibody development, inflammation-primed macrophage activation plays a major role in immune development. Therefore, macrophage activating factor should act as an adjuvant for immunization. The inflammation-primed macrophage activation process is the major macrophage activating cascade that requires participation of serum vitamin D3-binding protein (DBP; human DBP is known as Gc protein) and glycosidases of B and T lymphocytes. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase efficiently generated the most potent macrophage activating factor (designated GcMAF) we have ever encountered. Administration of GcMAF (20 or 100 pg/mouse) resulted in stimulation of the progenitor cells for extensive mitogenesis and activation of macrophages. Administration of GcMAF (100 pg/mouse) along with immunization of mice with sheep red blood cells (SRBC) produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days. Thus, GcMAF has a potent adjuvant activity for immunization. Although malignant tumours are poorly immunogenic, 4 days after GcMAF-primed immunization of mice with heat-killed Ehrlich ascites tumour cells, the ascites tumour was no longer transplantable in these mice.

Evaluation of serum CA15-3 determination with CEA and TPA in the post-operative follow-up of breast cancer patients

The usefulness of post-operatively serial serum CA15-3 determination with CEA and TPA was evaluated in a group of 285 breast cancer patients. In particular, the CA15-3 sensitivity to 'early' diagnosis and monitoring of the response to treatment of breast cancer relapses, was compared with those of the two other markers in order to define the most suitable association. Moreover, in a group of 169 non relapsed patients with a prolonged follow-up (40 +/- 8 months; mean +/- s.d.) CA15-3 specificity was investigated. During post-operative follow-up in 27 (10%) patients, distant metastases occurred. In most of them, elevated values of one or more tumour markers were the first pathological sign and CA15-3, CEA and TPA sensitivity to 'early' diagnosis of metastases were 46%, 7% and 63% respectively. When each tumour marker was considered in combination, CA15-3-CEA-TPA association showed a higher sensitivity (87%) than both CA15-3-TPA (83%) and the CEA-TPA (70%). Serum CA15-3 increase preceded the certain sign of metastases 2.7 +/- 2.6 months (mean +/- s.d.). Shortly before appearance and during treatment of distant metastases, constant elevation and/or progressive increase in serum CA15-3 values occurred in all evaluated patients except three in whom isolated elevated values were found as well. In 24 (14%) of 169 non relapsed patients with prolonged follow-up (40 +/- 8 months; mean +/- s.d.) high serum CA15-3 values occurred. In 16 of these 24 patients, an isolated elevated value was found, while four (2.3%) or the eight remaining ones with constant elevation and/or progressive increase were falsely suspected of metastases. In this group of non relapsed patients, chronic liver failure, diabetes and/or hepatic steatosis were the reasons more commonly responsible for the CA15-3 increase. In metastatic patients, no organ-specificity was shown either by CA15-3 or by CEA and TPA. In these patients serum TPA values showed the highest sensitivity and paralleled clinical and/or instrumental signs better than the CA15-3 and even more than CEA values. These data indicate that in the post-operative follow-up of breast cancer patients, TPA is the most useful tumour marker and TPA-CA15-3 the most suitable association. Contemporaneous measurement of serum CEA levels only slightly increases sensitivity and positive predictive value of TPA-CA15-3 combination.

Bovine-associated mucoprotein: de novo synthesis by nonmammary tissues

Bovine tissues were cultured in vitro in the presence of carbon-14 amino acids and tritiated hexosamine to examine the de novo synthesis of the milk fat globule glycoprotein bovine-associated mucoprotein, by selected tissues. Among tissues examined, the relative synthesis of bovine-associated mucoprotein was highest in mammary tissue. The de novo synthesized bovine-associated mucoprotein in mammary and lacrimal gland cultures when examined for incorporation of carbon-14, had similar sedimentation profiles in sucrose density gradients and incorporated the same relative amount of carbohydrate. The bovine-associated mucoprotein synthesized by lung and spleen cultures sedimented in similar fashion to mammary gland bovine-associated mucoprotein when incorporation of carbon-14 was used as the marker, but it displayed greater heterogeneity when evaluated for tritium incorporation. Bovine-associated mucoprotein in the lung and spleen incorporated relatively less carbohydrate than that synthesized by mammary tissue. These findings support the concept of intertissue heterogeneity, which had been suggested by previous studies.

Inhibition of rat mammary tumor growth by purified protein A--a potential anti-tumor agent

Intravenous inoculations of purified Protein A of Staphylococcus aureus Cowan I cause significant (p less than 0.01) regression of di-methyl-benz-anthracene (DMBA)-induced mammary adenocarcinomas in Sprague-Dawley rats. Direct tumor cell counts of treated tumors showed fewer (p less than 0.005) viable tumor cells than did tumors from untreated controls. Plasma immunoglobulin G concentration showed a significant (p less than 0.05) increase compared to that of controls. However, the concentration of immune complexes and percentages of T-rosettes did not change. Peripheral blood mononuclear cells (PBMNC) from treated animals showed increased cytotoxicity (p less than 0.005) compared to that of controls. Plasma of treated animals potentiated PBMNC cytotoxicity (p less than 0.05) and showed increased antibody and complement-mediated cytotoxicity (p less than 0.025). The exact mechanism of protein A-induced potentiation of anti-tumor immune reactivities leading to tumoricidal response is not known. However, our data are suggestive of the involvement of both cellular and humoral immunity of the host in the tumor regressive phenomenon.

Quantitation of human mammary epithelial antigens in cells cultured from normal and cancerous breast tissues

A sensitive radioimmunoassay technique was developed to quantitate the level of human breast celltype specific antigens on cells from normal breast and from various established cell lines of breast and nonbreast origins. Polyacrylamide gel electrophoresis revealed four major proteinaceous components (150,000; 75,000; 60,000; and 48,000) in human milk fat globule membranes that were used to immunize rabbits in order to elicit antimammary epithelial cell antibody. Antisera obtained were rendered specific by absorptions and were able to recognize three specific mammary epithelial components of the breast epithelial cell. Human mammary epithelial (HME) antigen expression was highest (1290 ng/10(6) cells) in normal breast epithelial cells from primary cultures of normal breasts. Lower levels (range: 955 to 330 ng/10(6) cells) were found in breast epithelial cells from cell lines established from cancerous breast tissue. Cells of nonbreast origins as well as fibroblasts from breast gave much lower values (less than 30 ng/10(6) cells). On treatment, with trypsin, of two breast epithelial cell lines (MDA-MB-157 and MCF-7) 80 to 85% of their HME antigen expression was lost, suggesting that a majority of these breast antigens reside on the cell surface.

Analysis of heteroantisera to cells from human malignant effusions by immunofluorescence and protein A binding

Using cultured cells derived from human malignant effusions, hetero-antisera were raised in rabbits. The antisera were sequentially absorbed on various human non-tumour cells, reactivity being monitored by immunofluorescence and 125I-labelled staphylococcal protein A assays. The absorbed antisera possessed common reactivity to all tumour cells assayed. This reactivity was not histogenically determined, and our data suggest that it was not directed to oncofoetal antigens.