Spontaneous Reticulum Cell Sarcoma Research Articles

IL-10 production in a CD5 + B cell lymphoma arising in a CD4 monoclonal antibody-treated SJL mouse

A majority of SJL mice develop spontaneous reticulum cell sarcomas (RCS) at about 1 year of age which can be transplanted into young SJL recipients. Previous studies have shown that RCS tumors are of B cell lineage, and that the development of these lymphomas and their subsequent growth depends upon host-derived T helper cell factors. In vivo treatment of SJL mice with anti-CD4 monoclonal antibody (mAb) prevents the development of the characteristic B lymphomas. Most of the mAb-treated animals were tumor free and had a significantly prolonged life span. However, one such CD4 mAb-treated mouse developed a transplantable IgM + CD5 + B cell lymphoma (designated NJ101), which has not previously been described in SJL/J mice. NJ101 is clonal on the basis of a discrete non-germ line Ig heavy chain gene rearrangement by Southern blot analysis. Unlike the sIg − CD5 − transplantable RCS-X cell line, the IgM + CD5 + NJ101 lymphoma cells will grow in immunocompromised hosts, such as irradiated recipients or in recipients treated with CD4 mAb in vivo. The RCS (B cell) lymphoma requires CD4 + T cells for progressive growth, whereas the growth of the CD5 + B lymphoma cells is enhanced by the removal of such cells. Thus, CD5 + B cell clonal development may be aided by the removal of regulatory T cells and/or the malignant CD5 + B cells may produce their own growth factors in an autocrine manner. Examination of IL-10 message by quantitative polymerase chain reaction techniques indicate that the CD5 + B lymphoma cells produce increased levels of IL-10 relative to normal LN cells or purified RCS lymphoma cells. These results suggest that two different types of B cell tumors, both of which can develop in SJL mice, have different growth requirements. Furthermore, treatment to prevent the occurrence of the characteristic RCS malignancy of SJL mice may lead to the development of another form of B cell neoplasia.

The SJL/J T cell response to both spontaneous and transplantable syngeneic reticulum cell sarcoma is mediated predominantly by the V beta 17a+ T cell clonotype.

Previous studies have revealed that the reticulum cell sarcoma (RCS) of SJL/J (H-2s, IE-) mice express an "IE-like" stimulatory tumor-associated antigen, the expression of which is requisite for stimulating host T cells necessary for tumor growth. Herein, we present evidence that the predominant T cells raised in the syngeneic response to both spontaneous and transplantable RCS tumors are of the V beta 17a TCR clonotype. The V beta 17a+ clonotype of T cells has been shown to interact with IE allogeneic specificities. We demonstrate that all four characterized RCS-specific T cell hybridomas stained positively for the anti-V beta 17a mAb, KJ23a. Additionally, KJ23a, when added to cocultures of the T cell hybridomas and RCS tumors, inhibited the release of IL-2 by the hybridomas. Further, KJ23a was shown to markedly inhibit the proliferation of SJL/J T cells when cocultured with either spontaneous or transplantable RCS tumor cells. When analyzed by flow cytometry, the T cell blast population raised in response to both spontaneous and transplantable RCS were greater than 80% KJ23a+. These T cells were brightly stained by the anti-CD4 mAb, Gk1.5, and, therefore, represent class II-responsive T cells. In corroboration of the in vitro data, T cells derived from mesenteric lymph nodes of RCS tumor-bearing mice had likewise undergone a similar expansion of V beta 17a+, CD4+ T cells. Together, these results indicate that KJ23a+ T cells play an important and predominant role in the response of SJL/J mice to spontaneous RCS tumors and provide further suggestive evidence that the stimulatory antigen(s) on the RCS tumor is IE or an "IE-like" molecule. Significantly, the important role V beta 17a+ T cells play in the response to RCS suggests a potential therapeutic role for KJ23a mAb in the intervention and prevention of RCS tumors in SJL/J mice.

Intimate host-tumor interaction in the spontaneous reticulum cell sarcoma of SJL/J mice: is it an exceptional case?

Intimate host-tumor interaction in the spontaneous reticulum cell sarcoma of SJL/J mice: is it an exceptional case?

The SJL/J Spontaneous Reticulum Cell Sarcoma: New Insights in the Fields of Neoantigens, Host-Tumor Interactions, and Regulation of Tumor Growth

Publisher Summary The biology of cancer has been an area of intensive investigation for several years. Cancer remains one of the most challenging fields in the 20th century. Research in cancer has attracted scientists from numerous disciplines and has provided the impetus for investigations in molecular biology, biochemistry, and immunology. Convincing evidence of immune surveillance has been provided in the areas of neoantigens, host immune response, and regulation. However, the evidence was primarily derived from experimental studies in animals using virally induced tumors or long-term transplantable or chemically induced tumors. The spontaneously arising reticulum cell sarcoma (RCS) of SJL/J mice is a good experimental tumor system for investigation. The heterogeneity of the tumor with an unknown cell origin resembles several ill-defined spontaneous tumors in man. Because the RCS tumor system offers several unique features, several studies have provided experimental evidence for new concepts in the biology of SJL/J RCS. The RCS tumor system also resembles several human neoplastic diseases such as Hodgkin's and other undifferentiated lymphomas and, therefore, can be used as a model system to investigate human neoplasia.

Opsonization of tumor-reactive T cells in SJL/J mice bearing syngeneic tumors.

The role of antigen-reactive cell opsonization (ARCO) in a syngeneic tumor system and its effect on tumor progression was investigated. Thus, anti-tumor reactive T cells were prepared in vivo by immunization of normal SJL/J mice with mitomycin C-inactivated tumor cells of the syngeneic transplantable reticulum cell sarcoma (RCS) line LA-6. Dividing cells were subsequently labeled by injecting iodo-2-deoxyuridine (125IUdR) into the same animals 3 days later. Antigen-reactive cells (*ARC) present in the radiolabeled, nylon wool-fractionated spleen cell population taken from these mice on day 4 and injected IV into syngeneic SJL/J mice bearing LA-6 tumors were diverted to the liver and away from the spleen. The effect was maximal by 8 days following inoculation of tumor cells, and was specific inasmuch as 125IUdR-labeled cells prepared by immunization with allogeneic spleen or tumor cells which were not opsonized in day-8 LA-6 tumor-bearing mice. Opsonization of *ARC in day-8 LA-6 tumor-bearing mice was completely abrogated by either prior injection of heat-aggregated immunoglobulin into the mice or preincubation of the *ARC in solubilized tumor antigen before injection into tumor-bearing mice, demonstrating the involvement of Fc receptors in the host and antigen-specific receptors on the *ARC, respectively, in the opsonizing process. When anti-LA-6 reactive T cells were incubated in serum from LA-6 tumor-bearing mice and then injected IV into normal syngeneic SJL/J mice, a similar liver diversion was observed. Serum from cyclophosphamide-pretreated mice injected with LA-6 or serum from mice given mitomycin C-inactivated LA-6 cells did not cause opsonization of tumor-reactive T cells, while a mixture of these two sera did have some *ARC opsonizing activity. Further experiments with SJL/J mice bearing spontaneous RCS tumor indicate that tumor-reactive T cells are also opsonized in these mice. The above studies and others suggested that ARCO may play an important role in vivo in the survival of tumors.

Immunodeficiency and reticulum cell sarcoma in mice segregating for hrs/j and sjl/j genes

Hairless (hr/hr) mice segregating for SJL/J and HRS/J genes (SJL-HRS) were compared to their haired counterparts with respect to immune responsiveness, tumour development and ecotropic murine leukemia virus (MuLV) expression. Homozygosity at the hairless locus did not affect expression of MuLV. There was however, a significant depression of the cellular immune response of these mice as characterized by depressed reactions in phytohemagglutinin, concanavalin A and mixed leukocyte assays. Haired and hairless mice did not differ significantly in response to B-cell mitogens or in production of cytotoxic antibody. The depressed cellular immune response in hr/hr mice is associated with a distinctive histologic type of spontaneous reticulum cell sarcomas. The importance of these results in relation to previous studies of HRS/J hairless mice is discussed.

Cell and cell-free transplantation experiments with a mouse reticulum cell sarcoma.

Quantitative cellular assays of the transplantability of 19 spontaneous reticulum cell sarcomas (RCS) of the BC3F1 mouse were carried out by injecting serial dilutions of monodispersed cells into syngeneic hosts through the intravenous, intracranial and subcutaneous routes. A clear relationship was found between the size of the inoculum and the incidence of tumour takes by all routes, but even for inocula of 5 million cells only 13 tumors grew in one or more of the transplanted recipients. The intravenous route of injection was found to be the most effective, both in terms of the absolute number of tumor takes and the number of cells necessary to produce a given level of takes. The survival of the animals injected intravenously was related to the number of cells received in that earlier deaths occurred with the most concentrated cell suspensions. Attempts to transmit the tumor by cell-free extracts injected into newborn or 1-month-old syngeneic hosts failed to substantiate the possible presence of a specific leukemogenic agent.

Suppression of spontaneous reticulum cell sarcoma development and of syngeneic stimulator cell by anti-mu treatment of SJL/J mice.

The cellular origin of reticulum cell sarcoma (RCS) in SJL/J mice was studied by comparing the incidence of spontaneous RCS in control mice and in mice suppressed with goat anti-mu Ig from birth on. At 10 months of age anti-mu suppressed mice had 0% RCS as opposed to 60% in control mice. Growth of two i.v. injected transplantable RCS lines in anti-mu suppressed mice was approximately 60% as compared with growth in normal SJL/J mice. Proliferative responses of thymus and lymph node cells from anti-mu suppressed mice to RCS, mitomycin-treated syngeneic spleen cells (M. Spl.) Con A, and PHA were entirely normal. However, M. Spl. from anti-mu suppressed mice caused minimal or no stimulation of T cells from normal or anti-mu suppressed responders. The results suggest that the normal syngeneic stimulator cell is of B cell origin, either representing a direct precursor of RCS or indirectly influencing RCS appearance. A B cell origin of RCS is, furthermore, in agreement with some of its characteristics, such as surface markers (Ia antigens, Ly b) and in vivo localization properties.

Inappropriate alloantigen-like specificities detected on spontaneous and transplantable reticulum cell sarcomas of SJL/J mice.

SummaryThe immune response of SJL/J (H‐25) mice to syngeneic reticulum cell sarcoma (RCS) tumour cells was investigated. The nature of tumour‐associated antigens was examined by immunological and biochemical techniques. Reticulum cell sarcomas of different origins (spontaneous, transplantable and cultured cell lines) stimulate a strong syngeneic response measured by [3H]‐thymidine incorporation. However, only the cell line were able to stimulate a syngeneic cell‐mediated cytotoxic response. Further analysis of the syngeneic response revealed that RCS cells express inappropiate alloantigenic specificities on their surface. Thus, evidence is provided which demonstrates that RCS tumour cells carry antigens which cross‐react with BALB/c (H‐2d) and C57BL/6 (H‐2b) alloantigens. The presence of inappropriate antigens in the in vitro lines was detected by cell‐mediated cytotoxicity, cytotoxic antibody and immunofluorescence whereas antigens on in vivo lines and spontaneous RCS were detected primarily by immunofluorescence. Conversely, H‐25 expression on the in vitro lines was detected only by immunofluorescence whereas the H‐25 of the in vivo lines were detected by cytotoxic antibody. By these assays inappropriate antigens were not detected on normal SJL/J lymphocytes. Immunochemical analysis of the inappropriate antigens by two‐dimensional gel electrophoresis was performed with SJL/J anti‐BALB/c and monospecific anti‐H‐2Dd sera. These sera precipitated 45,000 MW molecules from BALB/c lymph node cells and from SJL/J in vivo and in vitro RCS tumour which appeared very similar. The sera also precipitated molecules from SJL/J lymph node cells which resemble the BALB/c and RCS molecules. Thus, RCS tumours express inappropriate alloantigens which may be cryptic on normal cells. The biological significance of these tumour‐associated antigens in vivo is discussed briefly.

Isolation of transforming murine leukemia viruses from mice with a high incidence of spontaneous lymphoma.

Murine leukemia viruses capable of malignant transformation of mink tissue culture cells have been isolated from an AKR thymoma cell line and from a spontaneous reticulum cell sarcoma in an NIH Swiss mouse partially congenic for the AKR ecotropic virus-inducing locus Akv-2. In contrast to the recently described mink cell focus-inducing strains of murine leukemia virus, at least one of the two transforming strains is replication defective. Nonproducer mink cells carrying the genome of the transforming virus of AKR origin have been isolated, and pseudotype transforming viruses generated.

Strain-, Age-, and Tumor-Dependent Distribution of Terminal Deoxynucleotidyl Transferase in Thymocytes of Mice

The distribution of terminal deoxynucleotidyl transferase (TdT) peak I and peak II in thymuses and peripheral lymphoid tissues was examined in a variety of mouse strains in relation to tumor burden and age. TdT peak I was found to be present in all strains at comparable levels, which did not change with age. TdT peak II levels were also comparable for the strains examined at 1 week of age. In contrast to peak I, however, in NIH Swiss and AKR mice, peak II activity decreased rapidly at 2 weeks of age and by 6 weeks of age less than 2% of the initial activity remained. In C57BL/6 mice there was a similar loss of peak II activity with age although this change started at about 4 months of age and by 8 months of age approximately 15% of the initial activity remained. These changes did not appear to be due to the presence of an inhibitor. Leukemic C57BL/6 and AKR mice were also examined for TdT. Both strains characteristically had TdT peak I in peripheral lymphoid tissues infiltrated with transformed thymocytes. AKR mice had only TdT peak I in the thymus, whereas C57BL/6 thymuses had both peak I and II at levels comparable to age-matched controls. No aberrant distribution of TdT was observed in a spontaneous reticulum cell sarcoma or Rauscher MuLV-induced erythroblastosis.

Temperature-dependent rosette formation by mouse lymphoma cells as a result of viral hemadsorption.

Cells from several mouse lymphomas formed rosettes with nonsensitized foreign erythrocytes through C-type virus particles clustered on the cell surface in serum-free medium held at 4 degrees C. This type of rosetting was found most typically in a lymphoma induced by Rauscher leukemia virus in tissue culture (RD-12), but it also occurred in 23 of 61 spontaneous thymic lymphomas in AKR mice. Chemically or X-ray-induced leukemias and spontaneous reticulum cell sarcomas did not form rosettes. The nature of the rosette formation may be interpreted as viral hemadsorption, with a possible relationship to hemagglutination by murine leukemia viruses. The receptor on virus particles was trypsin sensitive and showed high affinity to serum inhibitors (RIF). Serum rosette-inhibiting activity was assessed by a quantitative rosette inhibition test; rosette inhibition proved widely distributed among species. Physicochemical properties of serum RIF and their function both in vivo and in vitro were described. Rosette formation with similar temperature requirements, previously reported in a mouse lymphoma carrying membrane-bound heterophile cold hemagglutinin, was readily distinguished from viral hemadsorption by its insensitivity to mouse serum RIF.

Epidemiological and pathological studies of reticulum cell sarcoma in mice (C57BL-Cne x C3H-Cne)F 1

Life-long observations on untreated animals have shown that spontaneous reticulum cell sarcomas (RCS) developed in 56.5 % male mice of the hybrid (C57BL/Cne x C3H/Cne) F1 strain; the average age at death of mice with tumors was 949 days, compared with 929 days for all causes: no age-specific peak of mortality has been shown to occur over the entire life span of the animals. Histologically, the spleen and all the lymphnodes, including the mesenteric node, were always invaded; neoplastic growth was found less frequently in kidneys, liver and lungs (77, 70, and 40%, respectively), only occasionally in other organs such as adrenals and testes, and never in the thymus. The tumor was predominantly composed of a single type of neoplastic cells, resembling highly undifferentiated reticular cells, typically proliferating from the periarteriolar region of the lymphatic follicles in the spleen. The monomorphic aspect of the tumor cell population suggests that RCS in this strain of mice may be classified as type A according to Dunn. Electron-microscopy observations showed the presence of a few virus-like particles both in tumor cells and in sediments from cell-free extracts. Transplantation of cells from spontaneous RCS into both normal and lethally-irradiated syngeneic recipients was successful only in 4 out of 7 experiments, regardless of the tissue of origin of the neoplastic cells (spleen, lymphnodes or bone marrow). Virus-like particles were seen with higher frequency in transplanted tumors. Inoculation of cell-free extracts into neonatal mice of low-leukemia strains has not so far been successful. Splenectomy of young animals as well as the intravenous injection of syngeneic bone marrow cells immediately following a lethal dose of whole-body X-irradiation significantly reduced the frequency of spontaneous tumors.

Analysis of the immunosuppressive and oncogenic effects of heterologous antilymphocyte serum

Abstract Heterologous antilymphocyte serum (ALS) or its purified globulin fraction (ALG) is being used in man with increasing frequency to prolong the survival of renal, hepatic, and cardiac allografts. One of its complications is an increased incidence of malignant lesions. It is not known whether this complication is the result of two distinct properties of ALS, that is, immunosupression and oncogenicity, or if it is the result of ALS being a more powerful and specific immunosupressive agent. We have used the inbred SJL/J mouse line to compare the immunosuppressive and oncogenic properties of ALS with those of another potent immunosuppressive agent, procarbazine. In this mouse line older animals (nine to fourteen months) have a 30 to 50 per cent incidence of spontaneously developing reticulum cell sarcoma. Treatment of young (five to six weeks) animals with antimouse ALS resulted in a 90 per cent incidence of reticulum cell sarcoma by the fifth month and a twofold prolongation of skin allograft survival. However, treatment of young animals with procarbazine in doses sufficient to produce a twofold prolongation of skin allograft survival did not increase the incidence of spontaneous reticulum cell sarcoma. It thus appears that the oncogenic properties of ALS (ALG) are related to some specific effect on the host's immune system rather than just to increased immunosuppression.

Analysis of the immunosuppressive and oncogenic effects of heterologous antilymphocyte serum

Heterologous antilymphocyte serum (ALS) or its purified globulin fraction (ALG) is being used in man with increasing frequency to prolong the survival of renal, hepatic, and cardiac allografts. One of its complications is an increased incidence of malignant lesions. It is not known whether this complication is the result of two distinct properties of ALS, that is, immunosupression and oncogenicity, or if it is the result of ALS being a more powerful and specific immunosupressive agent. We have used the inbred SJL/J mouse line to compare the immunosuppressive and oncogenic properties of ALS with those of another potent immunosuppressive agent, procarbazine. In this mouse line older animals (nine to fourteen months) have a 30 to 50 per cent incidence of spontaneously developing reticulum cell sarcoma. Treatment of young (five to six weeks) animals with antimouse ALS resulted in a 90 per cent incidence of reticulum cell sarcoma by the fifth month and a twofold prolongation of skin allograft survival. However, treatment of young animals with procarbazine in doses sufficient to produce a twofold prolongation of skin allograft survival did not increase the incidence of spontaneous reticulum cell sarcoma. It thus appears that the oncogenic properties of ALS (ALG) are related to some specific effect on the host's immune system rather than just to increased immunosuppression.

Neoplasms of the Hematopoietic System in Nonhuman Primates: Report of One Spontaneous Tumor and Two Leukemias Induced by Procarbazine<xref ref-type="fn" rid="FN2">2</xref>

Three neoplasms of the hematopoietic system in nonhuman primates are reported. A spontaneous reticulum cell sarcoma arose in an adult African green monkey (Cercopithecus aethiops), and myelogenous leukemias were induced in 2 female rhesus monkeys (Macaca mulatta) at ages 17 months and 5½ years after treatment with procarbazine hydrochloride. Transplantation of the reticulum cell sarcoma to progeny of the donor and the myelogenous leukemias to newborn rhesus monkeys was unsuccessful. No virus particles were detected by electron microscopy, and no viruses were isolated after tissue culture passage.

Transplantation behavior and cytogenetic characteristics of a spontaneous reticulum cell sarcoma in the golden hamster.

AbstractDuring a period of 2 1/2 years, 33 spontaneous reticulum‐cell sarcomas arose in our colony of golden hamsters. One of the tumors, made transplantable in the solid and the ascitic form, is described with regard to behavior in homologous hosts and to cytogenetic characteristics. During four years of transplantation, the tumor changed its pattern of growth and, after an initial phase of localized growth, displayed a leukemialike mode of spread resulting in the death of the hosts on the 6th or 7th day irrespective of site of transplantation. Animals of the same passage reacted differently to tumor implantation: some hamsters developed large tumors without tumor cell spread, others showed very small tumors with heavy tumor cell dissemination. These different modes of growth are assumed to be dependent on host factors.Chromosome analyses were carried out on tumor cells of different transplantation generations. The chromosomes in cells of the 38th generation did not differ from normal hamster cells, except for a higher variation in the number of chromosomes. Within the next 15 passages the karyotype changed considerably, but from then on remained stable with a stemline of 44 chromosomes and six markers. The late replication pattern of sex chromosomes and of most of the autosomes seems to be the same for both normal hamster cells and tumor cells.The DNA content of the tumor cells was found to correspond to the modal chromosome number.No causal relationship between changes in growth characteristics and in karyotype could be established.