Receptor sites for complement and for immune complexes on human nonhemopoietic tumor cells

Immunohistological Patterns of Immunoglobulins in Dysplasias, Benign Neoplasms and Carcinomas of the Breast

IgA, IgG, IgM and IgE were studied in 61 carcinomas, 24 tissues peripheral to carcinomas, 16 benign neoplasms and 15 dysplasias of the breast. Mono- and double-layer direct immunofluorescence procedures applying FITC- and TRITC-conjugated antisera were used on cryostat and paraffin sections for evaluation of immunoglobulins in plasma cells, cancer cells and ductal epithelium. Plasma cells of all Ig classes were more frequent in carcinomas, especially of medullary and poorly differentiated ductal types, than in benign lesions. In all groups of benign lesions and in carcinomas with scanty lymphocytes and plasma cells there was a predominance of IgA-synthesizing plasma cells. Carcinomas with marked local response had an increased proportion of IgG cells. IgE plasma cells were rare. IgA and IgM were more frequent in ductal epithelium than in cancer cells, especially of poorly differentiated tumors. No appreciable IgG was observed in ductal or cancer cells. Our results indicate a correlation between immunohistologic patterns of immunoglobulins and histologic characteristics of carcinomas.

Metastatic melanomas express inhibitory low affinity fc gamma receptor and escape humoral immunity

Our research, inspired by the pioneering works of Isaac Witz in the 1980s, established that 40% of human metastatic melanomas express ectopically inhibitory Fc gamma receptors (FcγRIIB), while they are detected on less than 5% of primary cutaneous melanoma and not on melanocytes. We demonstrated that these tumoral FcγRIIB act as decoy receptors that bind the Fc portion of antimelanoma IgG, which may prevent Fc recognition by the effector cells of the immune system and allow the metastatic melanoma to escape the humoral/natural immune response. The FcγRIIB is able to inhibit the ADCC (antibody dependent cell cytotoxicity) in vitro. Interestingly, the percentage of melanoma expressing the FcγRIIB is high (70%) in organs like the liver, which is rich in patrolling NK (natural killer) cells that exercise their antitumoral activity by ADCC. We found that this tumoral FcγRIIB is fully functional and that its inhibitory potential can be triggered depending on the specificity of the anti-tumor antibody with which it interacts. Together these observations elucidate how metastatic melanomas interact with and potentially evade humoral immunity and provide direction for the improvement of anti-melanoma monoclonal antibody therapy.

Fc gamma receptors and cancer

FcgammaRs are a family of heterogeneous molecules that play opposite roles in immune response and control the effector functions of IgG antibodies. In many cancers, IgG antibodies are produced that recognize cancer cells, form immune complexes and therefore, activate FcgammaR. The therapeutic efficacy of monoclonal IgG antibodies against hematopoietic and epithelial tumors also argue for an important role of IgG antibodies in anti-tumor defenses. Since the 1980s, a series of lines of evidence in experimental models and in humans strongly suggest that FcgammaR are involved in the therapeutic activity of monoclonal IgG antibodies by activating the cytotoxic activity of FcgammaR-positive cells such as NK cells, monocytes, macrophages and neutrophils and by increasing antigen presentation by dendritic cells. Since many cell types co-express activating and inhibitory FcgammaR, the FcgammaR-dependent effector functions of IgG anti-tumor antibodies are counterbalanced by the inhibitory FcgammaRIIB. In addition, some tumor cells express FcgammaR either constitutively, such as B cell lymphomas or ectopically, such as 40% of human metastatic melanoma. The tumor FcgammaR isoform is preferentially FcgammaRIIB, which is functional at least in human metastatic melanoma. This review summarizes these data and discusses how FcgammaRIIB expression may influence the anti-tumor immune reaction and how beneficial or deleterious this expression could be for the efficiency of therapeutics based on monoclonal anti-tumor antibodies.

Expression of low-affinity Fc gamma receptor by a human metastatic melanoma line

The class IIa of low-affinity receptors for the Fc region of IgG, Fc gamma RIIa, are expressed on immune cells. The cross-linking of Fc gamma RIIa by complexed IgG triggers activation of protein tyrosine kinase and internalization of immune complexes. In this report, we demonstrate the expression of Fc gamma RIIa by a human melanoma cell line (VIO) derived from a metastasis of a patient with regressive melanoma. The analysis of Fc gamma RIIa functions was performed in VIO cells and Fc gamma RlIa- or Fc gamma RIlb-transfected human melanoma cells (A375). The Fc gamma RIIa cross-linking induced protein tyrosine phosphorylation, including Fc gamma RIIa phosphorylation, and led to its internalization in a clathrin-independent way in human melanoma cells. Moreover, we showed that a part of internalized Fc gamma RIIa migrates in late endosomes, lysosomes and class II-containing compartments. These results suggest that melanoma cells can express functional Fc gamma RII, which might play a role in tumor-host relationships.

The murine Fc-gamma (Fc gamma) receptor type II B1 is a tumorigenicity-enhancing factor in polyoma-virus-transformed 3T3 cells

The murine receptor for the Fc portion of IgG is a molecule expressed by cells of the immune system. This study suggests the hypothesis that Fc gamma receptor type II B I (Fc gamma RIIB I) functions as a progression-enhancing factor when expressed ectopically on non-lymphoid tumor cells. It has been shown previously that BALB/c 3T3 cells transformed in vitro with polyoma virus (PyV) do not express Fc gamma RII but acquire the expression of this receptor following an in vivo passage in syngeneic mice. The specific Fc gamma RII transcript present in tumor cells was identified in this report as Fc gamma RIIB I (BI). In order to determine whether or not the ectopically expressed Fc gamma RII plays a role in the progression of these transformed cells, PyV-transformed 3T3 cells were transfected with BI-cDNA. The BI transfected cells were tested for their ability to form local tumors in syngeneic mice, as compared to transfected cells which express the co-transfecting neomycine resistance (neores) DNA alone or together with the lacZ gene. Fc gamma RIIB I expressors exhibited a significantly higher tumorigenic phenotype than FcR-negative controls, though both types of cells exhibited the same growth curve in vitro. The ability of Fc gamma RIIB I to act as a potentially tumorgenicity-enhancing factor was also demonstrated as Fc gamma RII was expressed by tumor cells, originating from inoculated Fc gamma RIIB I-transfected cells, or from inoculation of a mixture of receptor-positive and -negative cells. B I-expressing cells dominated the tumor-cell population over non-expressors. This dominance strengthened the hypothesis that FcR plays a role in tumor progression in vivo.

FcR may function as a progression factor of nonlymphoid tumors

Tumor progression is a multistep process involving genetic and epigenetic changes in a transformed clone. Some of these changes may be induced by host factors which may also select for transformed cellular variants with a high ability to survive and propagate. In this article we review studies showing that receptors for the Fc portion of IgG may be expressed on cells from human or animal tumors of nonlymphoid origin. We also review data demonstrating that at least with respect to cells transformed in vitro with Polyoma virus, transformation per se is not sufficient for the induction of Fc receptor expression. We also summarize preliminary data showing that Fc receptor expression is causally involved in conferring a high malignancy phenotype upon transformed cells. Possible mechanisms to explain these observations are discussed.

A study to analyze the origin of tumor cells in malignant fibrous histiocytomas. A multiparametric characterization

To study the derivation of tumor cells of malignant fibrous histiocytomas (MFH), their phenotypical marker profile was investigated and compared with those of malignant histiocytosis (MH) and of different types of soft tissue tumors (STT). The presence of the following markers was investigated: on paraffin sections, alpha-1-antichymotrypsin (ACT); on frozen sections antigens associated with lymphocytes, macrophages and fibroblasts, the enzymes acid phosphatase, nonspecific esterase, and beta-glucuronidase; and, on isolated and cultured cells, the receptors for EA-gamma and complement. Furthermore, the capacity to phagocytose sensitized erythrocytes and carbon particles was studied in vitro. MFH tumor cells and a part of other types of STT shared the expression of ACT and lysosomal enzymes with MH. They differed, however, from MH by the absence of monocyte/macrophage-associated antigens and by the expression of fibroblast-associated antigens, which property they had in common with other STT. MFH tumor cells were not able to form rosettes or to phagocytose Ig-sensitized erythrocytes, but they showed phagocytosis of carbon particles. The results strongly indicate that MFH tumor cells originate from (primitive) fixed mesenchymal cells and are not related to monocyte-derived histiocytes.

Establishment and characterization of neoplastic cells from a malignant fibrous histiocytoma. A possible stem cell line

Using the semisolid agar method, neoplastic three clones were isolated from a malignant fibrous histiocytoma. All clones represented morphologically only one type of cells having fine structure similar to that of histiocyte with multiple filopodia. The clones carrying Fc- and C3-surface receptors showed marked immunophagocytosis. They were positive for acid phosphatase, nonspecific esterase, and alpha-1-antitrypsin. These clones were able to display the potential for production of collagenous matrix. Moreover, inoculations of the each clone into nude mice resulted in productions of malignant fibrous histiocytoma with pleomorphic pattern. These tumors were composed morphologically of various types of cells such as immature, histiocyte-like, fibroblast-like, and multinucleated giant cells. These morphologic alterations of histiocytes occurred in all of the three clones in vitro. These findings suggest that the cloned cells established from the malignant fibrous histiocytoma are neoplastic histiocytes with capability to form various types of cells, a possible stem cell.

Benign and malignant fibrous histiocytomas of the soft tissues: functional characterization of the cultured cells

Cell cultures were carried out from fresh tumor tissues obtained from seven cases of histiocytic tumors of the soft tissues including four of malignant fibrous histiocytoma, two of benign fibrous histiocytoma, and one of giant cell tumor of tendon sheath. The cultured cells were studied by light and electron microscopy, rosette formation for surface receptors, immune phagocytosis, and enzyme cytochemistry. The culture of each tumor revealed a mixture of histiocyte-like cells, fibroblast-like cells, amd intermediate forms. Bizarre giant cells were numerous in the early cultures of malignant fibrous histiocytoma, but they were absent in the cultures of benign fibrous histiocytoma and giant cell tumor of tendon sheath. In all the seven cases the cultured cells exhibited several features characteristic of histiocytes: (1) surface receptors for the Fc-portion of immunoglobulin G; (2) surface receptors for the third component of complement; (3) immune phagocytosis of opsonized erythrocytes; and (4) lysosomal enzymes including alpha-naphthyl butyrate esterase, and acid phosphatase. These findings suggest that the histiocytic tumors of the soft tissues in discussion actually comprise the cells that have the functional property of histiocyte. The tumor cells in the surgical specimens presented essentially the same ultrastructural and enzyme histochemical characteristics as those of the cultured cells.

Monoclonal antibodies: potential role in radiation therapy and oncology

Specificity, which is a hallmark of the immune system, will be used in radiation oncology in both diagnosis and therapy through the application of radiolabelled monoclonal and polyclonal antibodies. Antigenic specificities, antibody preparations, and the tumor as a target for radiolabelled antibody is reviewed. Several clinical situations, i.e. single tumor cell suspensions, intraperitoneal single cells and masses, and solid tumors are reviewed in regard to both immune antibody targeting and specific differences between tumors in these regions. The concentration of tumor associated antigens is introductory to radiolabelled antibodies in diagnosis. In the radiation therapy of solid tumors, data regarding tumor dose, tumor effective half-life, varied antibody preparations, and the use of radiolabelled antibody as a method of tumor implantation is discussed using antiferritin 131I-IgG as a model as a model in hepatoma. The theoretical applications of monoclonal antibody integrated in cancer therapy are then presented as a new goal for future development.

Cells bearing Fc receptors in human malignant solid tumours

Fc-receptor-bearing cells forming EA rosettes with antibody-coated human erythrocytes (Ripley) were studied in cell suspensions and in purified preparations of mononuclear cells (MC) from 20 human malignant tumours. The EA rosettes were studied in preparations made by cytocentrifugation and the rosette-forming cells identified by their nonspecific-esterase activity and phagocytic capacity. Fc receptors were found on 16 +/- 20% of all cells in the primary cell suspensions. Significantly more tumour-infiltrating lymphocytes had detectable Fc receptors normal control subjects (14 +/- 6%). There was a significant correlation between the proportion of lymphocytes lacking T and B markers (null cells) and the proportion of lymphocytes with Fc receptors. Fc receptors were also found on most tumour-infiltrating macrophages, on some T lymphocytes and polymorphonuclear cells and on a smaller percentage of the tumour cells. The significance of the Fc receptor and its usefulness as a marker of "host infiltration" into the tumours is discussed.

Fc and complement receptors on malignant tumor cells

The Fc-C'-receptor-positive cells were investigated in tumor cell suspensions from 196 malignant tumors. The number of EA (Fc) and EAC' (C') rosettes was determined; the rosette-forming cells were identified cytologically, the cell suspensions were exposed to carbon particles, and they were grown in tissue culture. The results suggest that Fc or C' receptors might be present in malignant tumor cells as well as in host defence (inflammatory) cells invading the tumor.