Analysis of the idiotypic network in tumor immunity

Herein we have analyzed the expression of idiotopes associated with a monoclonal anti-tumor-associated antigen (TAA) antibody in DBA/2 mice which have progressively growing tumors or resist tumor growth. A panel of eight monoclonal antiidiotypic antibodies raised against a monoclonal antibody which reacts with a mouse mammary tumor virus cross-reactive qp52 envelope protein (TAA) of the L1210/GZL lymphoma was used to measure the expression of idiotopes in sera from different treatment groups. Significant correlations between the expression of certain idiotopes and the growth of the tumor or the establishment of anti-tumor immunity are seen. 1) Idiotypes detected by anti-idiotype D11 are high in anti-idiotype immunized progressor or tumor-susceptible mice and low or absent in regressor mice, i.e., the mice immunized with the protective 2F10 anti-idiotype; 2) the 3A4-detected idiotypes are less frequent or absent in irradiated tumor-immunized regressor mice than in untreated mice challenged with live tumor or progressor mice; 3) no difference in the anti-TAA titers is seen in mice in which the tumor growth is inhibited and in mice in which the tumor grows; 4) no difference in 11C1 idiotype + anti-TAA titer was observed between regressor and progressor mice; and 5) mice with normal or accelerated tumor growth have higher titers of idiotypes detected by a polyclonal anti-idiotype. These findings provide evidence for a regulatory idiotype network induced by the growing L1210/GZL tumor or by anti-idiotypic immunization. The titer of anti-TAA antibody does not correlate with the biology of tumor growth, but certain idiotopes correlate with either progressive or regressive tumor behavior. Therefore, the target of the idiotype regulation is likely to be anti-tumor T effector cells. Effective idiotype therapy of tumors must deal with the complexity of idiotype regulation induced by the tumor itself and is unlikely to be successful if anti-idiotypes are used only as internal mimicry of a TAA.     

The in vivo depletion of V beta 17a+ T cells results in the inhibition of reticulum cell sarcoma growth in SJL/J mice. Evidence for the use of anticlonotypic antibody therapy in the control of malignancy

Previous findings revealed that reticulum cell sarcoma (RCS) of SJL/J mice growth and survival depended on its ability to stimulate a potent host T cell response, by the means of a tumor-associated class II MHC molecule with IE-like specificities. Previously we presented evidence that the V beta 17a TCR+ clonotype of T cell was the predominant T cell involved in the host response to the tumor. We undertook our study to examine whether the depletion of the V beta 17a+ T cells, by the use of the anticlonotypic antibody, KJ23a, resulted in the inhibition of RCS tumor growth in vivo. We present evidence herein that supports this hypothesis. KJ23a-treated mice exhibited a complete reduction in T cells bearing the V beta 17a TCR. These mice exhibited a dramatic reduction in the in vitro proliferative response to RCS. Furthermore, the pretreatment of SJL/J mice with KJ23a mAb resulted in the complete loss in their ability to harbor RCS tumor. When tumor-bearing mice were treated with a single inoculum of KJ23a mAb within the first 7 days after the passage of tumor, the mice showed long term survival with diminishing tumor burden. These results demonstrated that the V beta 17a clonotype of T cells is required for the growth and maintenance of RCS tumor. Within the first 6 wk after tumor inoculation KJ23a-treated mice were capable of transferring tumor to naive syngeneic recipient mice despite the obvious lack of tumor growth in the treated donor animal. These results suggested that RCS tumors in the absence of V beta 17a+ T cells can persist for up to 6 wk in a state of "tumor dormancy." The predominant usage of the V beta 17a gene in RCS-specific T cells suggests that these T cells play an important role in the pathogenesis of RCS tumor. Furthermore, the positive therapeutic course taken by tumor-bearing mice upon the treatment with KJ23a mAb, demonstrates the enormous potential in anticlonotypic antibody therapy in the treatment of T cell-dependent tumors and diseases.     

Investigation of the growth and metastasis of malignant melanoma in a murine model: the role of supplemental vitamin A

Vitamin A possesses both wound-healing and antitumor actions. Vitamin A-induced fibroplasia results in subsequent increased collagen production and deposition. This effect of vitamin A has been shown to result in the production of collagenous capsules around several murine breast and lung tumor systems. This tumor encapsulation process can potentially convert a systemic disease to a local one that can be easily treated by tumor excision. The goal of the present study was to determine whether supplemental vitamin A could promote the encapsulation of a murine melanoma. Sixty DBA/2J male mice were inoculated intracutaneously with 1 x 106 Cloudman S91 melanoma cells using a 30-gauge needle. The mice were divided into three groups: a control group, a pre-vitamin A group, and a post-vitamin A group. The control mice were fed a commercial chow containing 15,000 IU of vitamin A and 6.4 mg of beta-carotene per kilogram diet, considerably more than the National Research Council's recommended daily allowance of vitamin A for normal mice. The control diet was, therefore, not vitamin A-deficient. The pre-vitamin A mice were fed the basal chow supplemented with 150,000 IU of vitamin A per kilogram diet for 10 days before inoculation and for the remainder of the study. The post-vitamin A mice were fed the vitamin A-supplemented diet beginning on the day of inoculation and continuing for the remainder of the study. Sixty days after inoculation, tumor growth was assessed and the five mice remaining in each group were euthanized. Ventral skin at the site of inoculation was harvested for histologic assessment of local tumor growth and invasiveness. The liver and lungs of each of these mice were also harvested for histologic assessment of tumor metastasis.Sixty days after tumor inoculation, a 60 percent survival rate was observed in the control group as opposed to the vitamin A-supplemented animals, which demonstrated a 100 percent survival rate in both groups (n = 5 in each group). Decreased mean tumor size and gross tumor in most vitamin A-supplemented animals were statistically significant when compared with the control animals. The control animals had a mean tumor size of 26.1 mm, whereas the post-vitamin A group had a mean tumor size of 5.7 mm. One hundred percent of the control group exhibited tumor; one animal had distant metastases. The pre-vitamin A group did not exhibit any tumor growth, and the post-vitamin A group exhibited tumor growth in 40 percent of animals. Neither vitamin A-supplemented group showed any evidence of distant metastases. The animals supplemented with vitamin A demonstrated decreased tumor growth and metastasis. This in vivo model may indicate a potential prophylactic and therapeutic role for supplemental vitamin A in the treatment of malignant melanoma.     

The immunological role of the thymus in the pathogenesis of virus-induced lymphomas. Suppression of cytolytic T-cell function

Thymectomy of young adult mice has been found to prevent virus-induced lymphomas which develop as the animals age. Thymectomy protects mice by removing a source of suppressor T cells which inhibit the generation of cytolytic T cells against autochthonous tumors. Furthermore, suppression is specific since T cells are regulated in their capacity to respond to syngeneic but not allogeneic tumor cells. To determine if suppression could be adoptively transferred, lethally irradiated, bone-marrow-reconstituted mice were inoculated with T cells from either normal or thymectomized mice. Only T cells from thymectomized animals transferred enhanced T-cell reactivity to syngeneic tumor cells. More importantly, T cells from thymectomized mice injected with virus protected recipients challenged with lethal doses of syngeneic tumor cells. We conclude that thymectomy protects mice from developing virus-induced T-cell lymphomas by removing a source of suppressor T cells which regulates the activity of specific cytolytic T cells directed against autochthonous tumor cells.     

Dual role of polymorphonuclear neutrophils on the growth of Ehrlich ascites tumor (EAT) in mice

We show that granulocytes (PMN) have a dual role in the development of Ehrlich Ascites Tumor (EAT) in mice. EAT intraperitoneal inoculation causes a local inflammatory reaction, ascites development and mortality that distinguish resistant and susceptible strains. In resistant mice (CAF1), there is a less pronounced PMN influx after EAT inoculation than in susceptible Swiss mice. Accordingly, the increase in peritoneal PMN numbers enhanced tumor growth in CAF1 mice, but had no effect in the susceptible Swiss animals. Contrastingly, PMN depletion had no effect in resistant mice but facilitated tumor growth in susceptible animals. Though no differences were noted between the strains in peritoneal cell spreading and hydrogen peroxide release after tumor inoculation, in vitro PMN cytotoxic activity against EAT was significantly higher in susceptible Swiss mice. These data indicate a paradoxical dual role for PMN against EAT: while they help control tumor development in susceptible animals, they seem to enhance tumor growth in resistant mice.     

Specific T-cell factor production and lymphocytes in the direct surroundings of a subcutaneous allogeneic tumor.

Antigen-specific T-cell factors (TCF) play a role in the initiation of cellular immune responses. In allogeneic mouse-tumor models lymphocytes from the direct tumor surroundings of both euthymic and nude mice produce TCF. These lymphocytes produce TCF when collected already 1 day after subcutaneous (sc) injection of tumor cells. In contrast to euthymic mice, draining lymph nodes and spleen of nude mice did not contain TCF-producing lymphocytes at any stage after sc tumor cell injection. In sensitized euthymic mice TCF production by lymphocytes is significantly higher in the direct tumor surroundings than in draining lymph nodes or spleen. At 2 and 5 days after tumor cell injection, the mononuclear cell infiltrate of the tissue surrounding the tumor in euthymic mice showed low expression of Thy 1, CD3, TCR alpha beta, TCR gamma delta, CD4, CD8, and asialo GM1, whereas several lymphocytes and mast cells were positive for monoclonal antibody (mAb) 14-30 (directed against TCF). In both euthymic and nude mice, sc injected tumor cells showed apoptosis. In conclusion, the direct tumor surroundings are the first (and, for nude mice, the only) site of TCF production, sc injection of tumor cells attracts mAb 14-30-positive lymphocytes and renders mast cells positive for mAb 14-30.     

The role of tumor-derived cytokines on the immune system of mice bearing a mammary adenocarcinoma. I. Induction of regulatory macrophages in normal mice by the in vivo administration of rGM-CSF

Using a dimethylbenzanthracene-induced immunogenic nonmetastatic murine mammary adenocarcinoma in BALB/c mice, our previous work has shown that splenocytes from tumor bearers have reduced responses to both mitogens and Ag including tumor-associated Ag. NK and cytotoxic T cell activities are also reduced in splenocytes of tumor bearers. Mac-1+2+ macrophages induced in mammary tumor bearers are capable of down-regulating lymphocyte responses to mitogens and tumor-associated Ag by cell to cell contact interaction and increased PGE2 production. We have found that the tumor constitutively releases a granulocyte-macrophage (GM)-CSF-like factor in vivo and in vitro, which may be responsible for the systemic increase in cells of the macrophage lineage in tumor-bearing mice. A tumor cell line established from the in vivo tumor expresses and releases GM-CSF as shown by Northern and Western blot analyses. Daily i.p. injections for 3 wk of 10,000 U of rGM-CSF into normal mice induces hemopoietic and immunologic alterations similar to those observed in tumor bearers. Mac-1+ and/or Mac-2+ macrophages can also be detected in the spleens and bone marrow of the mice treated with rGM-CSF. Additionally, splenocytes from rGM-CSF-treated mice have reduced responses to mitogens and their peritoneal exudate cells can cause in vitro down-regulation of proliferative responses of lymphocytes from normal mice. The suppression can be partially reversed by the addition of indomethacin to the cultures suggesting that PGE2 may contribute to the effect. rGM-CSF enhances the in vitro release of PGE2 by the spleen, bone marrow, and peritoneal cells of normal mice. These data indicate that the high levels of GM-CSF constitutively produced by the tumor may be responsible for the hemopoietic changes and immunologic alterations observed in tumor-bearing mice.     

Tumor immunity in the mammary gland

Summary Mouse mammary tumor 410, which was derived from a spontaneously arising BALB/cf C3H mammary tumor, grows better in syngeneic BALB/c mice after injection into mammary fatpads than after injection into subcutaneous sites. This finding is consistent with the notion that the fatpad is an imunologically privileged site. However, no evidence that the mammary fatpad was immunologically privileged with respect to tumor transplantation antigens was found. Tumor cells were injected into mammary fatpads or SC. When the tumors became palpable they were surgically removed. One to three weeks later, the mice were challenged on the opposite side by injection of tumor cells either SC or into the mammary fatpad. The mice were immune after temporary growth of tumors either in the fatpad or SC. Regardless of the growth site of the immunizing tumor, the mice rejected the challenge tumor cells whether they were injected SC or into the fatpad.     

Tumor dormancy and the effect of selected drugs on the tumor-dormant state.

An animal model for studying tumor dormancy was established by two-way selection of tumor-progressive and nonprogressive (tumor-dormant state) ddY mice in the same basal stock. In the tumor-progressive (prg) substrain of mice, Ehrlich ascites tumor cells (2 x 10(7)) subcutaneously inoculated into the dorsal skin formed a progressive solid tumor. In the tumor-dormant substrain (drm) of mice, the same tumor cells did not grow at all but formed a small caked nodule (1 to 3 mm in diameter) within 1 week. Some of the tumor cells persisted in the nodule at least 3 months without apparent mitotic figures. Such dormant tumor cells emerged and revealed outgrowth to overt solid tumors after they were transplanted into the dorsal skin of prg mice or into athymic mice (C57BL/6J nu/nu). To estimate the predisposition of drm mice to form tumors, the effect of certain drugs on the tumor-dormant state was examined. Estradiol, progesterone, dexamethasone, prostaglandin E2, Cyclosporin A, and collagenase all failed to promote the emergence of dormant tumor cells in drm mice.     

Cytotoxic antibodies in the serum of C3H mice after inoculating them with spontaneous mammary gland tumor cells]

Complement-dependent cytotoxic antibodies against the cells of mammary tumor MMTI appeared in the blood of C3H/He and C3Hf mice at the terminal stage of tumor growth; at the same time the mice of the above-mentioned substrains showed no difference in the degree of reaction. The level of natural cytotoxic antibodies against MMTI tumor cells detected in old C3H/He and C3Hf mice significantly exceeded their level in young mice affected with tumor; however, MMTI tumor cells grew equally fast in both old and young animals. The sera of mice affected with tumor had a weak cytolytic activity against the cells of hepatoma 22a and did not affect L cells and embryonal fibroblasts. The sera were partially exhasted by spleen and renal tissues, as well as the cells of spontaneous mammary tumor obtained from syngeneic animals and were not exhausted by allogenic cells infected with Rauscher murine leukemia virus.     

The effect of irradiation in air or in hyperbaric oxygen on the Fib/T tumor in WHT mice pretreated with a hypoxic gas mixture

The effect of exposing WHT mice bearing the Fib/T tumor to a low-oxygen environment (8, 10, and 15% oxygen) for 48 h or 72 h before irradiation was compared, using an in vitro colony-forming excision assay, to the effect obtained when mice were pretreated with air. The response of the Fib/T tumor to radiation delivered in air was improved both by a 48-h and by a 72-h exposure of the animals to 8, 10, and 15% oxygen. However, the greatest tumor sensitization was achieved when mice were kept in 8% oxygen for 48 h before irradiation. These results are interpreted and discussed in relation to increases in the 2,3-DPG concentration, which were shown to occur when mice were exposed to a reduced oxygen environment. The relative importance of two models proposed to explain these findings is assessed. If mice pretreated with air were irradiated in hyperbaric oxygen, a similar tumor response was observed compared to that when mice were exposed to 8% oxygen for 48 h and then irradiated in air.     

Quantitative factors which determine the effect of the immune response on the growth rate of the Cloudman melanoma in the DBA/2 mice

We compared the growth rate of Cloudman melanoma in DBA/2 mice produced by injections of tumor cells taken from tissue culture (TC cells) to that of tumor cells prepared from tumor nodules already growing in DBA/2 mice (An cells). We found that small numbers of An cells grew better than TC cells. In contrast larger numbers of An cells grew less well than TC cells. We could make the growth rate of TC cells comparable to that of AN cells by (a) immunosuppressing recipient mice and/or (b) injecting the host with the proper dose of tumor cell proteins, debris and antigens extracted from the tumors with potassium chloride. The immunologic basis for both the tumor-retarding and tumor-promoting effects of the KC1 extracts was established by adoptive transfer experiments. Thus, some tumor cell products which have the potential to stimulate the immune response do so in a distinctive fashion depending in part on whether they are associated with viable tumor cells. The effects that nonviable cell-associated tumor products have on the immune response to viable tumor cells varies with their dose; they increase the magnitude of the immune response against the tumor at moderate doses but decrease it at higher or lower doses. The latter point may help explain the phenomenon of “sneaking through.”     

Immunosuppression in a murine B cell leukemia (BCL1): role of an adherent cell in the suppression of primary in vitro antibody responses

The ability of lymph node cells from mice bearing the BCL1 tumor to respond in vitro to mitogens, allogeneic cells, and both TI and TD antigens was investigated. The lymph nodes of such mice are not invaded with tumor cells and contain normal numbers of T and B cells. Nevertheless, at the peak of tumor burden in the spleen and blood (approximately 8 to 12 wk after injection with tumor cells), the lymph node cells from the tumor-bearing mice display markedly decreased responsiveness both to allogeneic cells and to antigens. In addition, small numbers of lymph node cells from the tumor-bearing mice suppress primary antibody responses of normal lymph node cells. This nonspecific suppression of antibody responses is mediated by a G-10 Sephadex adherent, non-T, non-B cell present in the nodes of the tumor-bearing mice. Since the BCL1 tumor model is in many respects similar to the prolymphocytic type of human chronic lymphocytic leukemia, the present results may be helpful in elucidating the mechanisms underlying the in vivo immunosuppression associated with lymphocytic neoplasms in humans.     

短小棒状杆菌对小鼠实体瘤及免疫功能的影响

目的研究短小棒状杆菌对H22荷瘤小鼠及其免役功能的影响。方法采用抑瘤实验、小鼠碳廓清实验、MTT法观察短小棒状杆菌对小鼠实体瘤和免疫功能的影响。结果短小棒状杆菌可使荷瘤小鼠的碳廓清指数、胸腺指数、脾脏指数升高,并由刀豆蛋白(ConA)、脂多糖(LPS)诱导体外小鼠T、B淋巴细胞增殖,能够抑制小鼠实体瘤生长。结论短小棒状杆菌能够增强小鼠机体免疫功能,并有抑瘤作用。     

The generation of tumor-specific in vivo protective immunity in the tumor mass from mice rendered tolerant to tumor antigens

Summary C3H/He mice were inoculated i.v. with 10⁶ heavily X-irradiated syngeneic X5563 plasmacytoma cells 3 times at 4 day intervals. When these mice received an appropriate immunization procedure consisting of i. d. inoculation of viable tumor cells plus the surgical resection of the tumor which enables i.v. nonpresensitized mice to produce anti-X5563 immunity, they failed to develop tumor-specific immunity. This was demonstrated by the abrogation in potential of spleen and lymph node cells to generate in vivo protective immunity. In contrast, the tumor mass from X5563 tumor-bearing mice which had received the i.v. presensitization contained comparable anti-X5563 tumor neutralizing activity to that obtained from the tumor mass from nonpresensitized, X5563 tumor-bearing mice. Such an in vivo protective immunity was revealed to be mediated by tumor-specific T cells. These results demonstrate the differential generation and antitumor capability of tumor infiltrating T cells and T cells in lymphoid organs from mice which are in the tumor-specific tolerant state. The results are discussed in the context of potential utilization of tumor infiltrating in vivo protective T cells to enhance the local tumor-specific immunity in tumor-specific tolerant mice.This work was supported by Special Project Research-Cancer Bioscience from the Ministry of Education, Science and Culture     

The immunomodulation of the natural killer activity of the splenocytes in C3HA mice during hepatoma 22a growth

A single injection of C3HA mice with various immunomodulators-ds-RNA, thymogene (TM) and cyclophosphamide (CY)--performed one day before transplantation of syngeneic hepatoma 22a cells led to a decrease in the tumor growth rate. The most prominent effect was found following the CY treatment. The NK cell activity estimated per spleen of mice treated with ds-RNA and TM was seen increased in comparison with the control mice not given the modulators. The rate of tumor growth was due probably to this fact. The protective effect of CY may be accounted for by a direct action of this agent on tumor cells.     

Effectiveness of indomethacin as an antitumor agent in Colon 26-bearing conventional and nude mice, and telomerase activity in the tumors.

The antitumor effect of indomethacin on Colon 26 tumor was investigated in conventional (CDF1) and nude mice (BALB/c nu/nu), and the telomerase activity in the tumor tissues treated with indomethacin was monitored. Growth of Colon 26 tumor was significantly suppressed with indomethacin treatment compared to the controls both in conventional and nude mice. And telomerase activity in the tumor tissues noticeably declined in contrast to normal somatic tissues (testis, liver and colon), which were not affected by indomethacin treatment. We also showed that indomethacin can suppress tumor growth in association with a preferential decrease in telomerase activity in tumor tissues both in conventional and nude mice to the same extent. This study suggests a method for investigating the mechanism of tumor suppression by indomethacin, and suggests that indomethacin might be useful as a novel agent for human cancer therapy.     

Development of a cellular immune response in a highly cancer-susceptible C3H/He strain of mice and its nonfactor substrain C3H/f after the transplantation of a syngeneic mammary gland tumor]

Syngeneic mammary gland tumor (MMT-1) grew slower in non-factor C3H/f (MTV-L) mice than in wirus-positive C3H/He (MTV-S) mice. The immunization of mice with tumor (MMT-1), inoculated and later excised, revealed a higher immune reactivity in the mice of the non-factor substrain. In studying the dynamics of the cytotoxic activity of lymphocytes in regional lymph nodes cytotoxically active lymphocytes were found to appear in C3H/f mice on day 6 after the inoculation of tumor (MMT-1), while the areactive state of lymphocytes was observed in C3H/He mice on days 3 and 24 and in C3H/f mice on day 24 after the inoculation of tumor (MMT-1). Spleen lymphocytes in C3H/f mice had no cytotoxic effect on tumor cells.     

Silkworm powder containing manganese superoxide dismutase regulated the immunity and inhibited the growth of Hepatoma 22 cell in mice

The effects of SOD contained silkworm powder on immune regulation and inhibition against Hepatoma 22 tumor cells in vivo were investigated. The activity of natural killer cell (NK) and the ConA-stimulated spleen proliferation were measured. The results found that the SOD-contained silkworm powder caused an enhancement on NK cell activity, which implied this material modulated the immune system in mice in vivo. The NK cell activities of Hepatoma 22 tumor modeled mice treated with silkworm powder including SOD were increased significantly compared to a modeled control and silkworm powder without SOD, reaching 36.18%. In addition, the ConA-stimulated spleen proliferation of SOD treated mice was higher than that of the controls. The treatment of SOD contained silkworm powder presented 40.3% of average inhibition rate to Hepatoma 22 tumor, showing stronger inhibition against tumor. There were no significant difference in body weight between modeled control and SOD silkworm powder feeding in Hepatoma 22 tumor modeled mice, suggesting the SOD silkworm powder is safety as an inhibitant to tumor. In conclusion, these findings demonstrate that administration of silkworm powder containing SOD results in activation of NK cells and immunity, suggesting the silkworm powder containing SOD plays a positive role in tumor inhibition.