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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human high-affinity IgG receptor, hFc gamma RI (CD64), is exclusively expressed on myeloid cells, where it serves an important role as a (cytotoxic) trigger molecule. To establish an in vivo model for analysis of the role of hFc gamma RI in immunity, we developed a novel transgenic mouse model. The human Fc gamma RIA gene, with endogenous regulatory sequences, was used to generate two lines of transgenic FVB/N mice. Immunohistochemical and flow cytometric studies showed that hFc gamma RI expression was restricted to myeloid cells. Monocytes, macrophages, and polymorphonuclear neutrophils (PMN) expressed physiologic hFc gamma RI levels, whereas lymphocytes and mast cells lacked expression. Human Fc gamma RI expression was regulated in vivo by the cytokines IFN-gamma (exactly as in humans) and IL-10. The transgenic receptor proved functional and bound human tumor cells via anti-hFc gamma RI-based bispecific antibodies. hFc gamma RI could, furthermore, be efficiently targeted in vivo by CD64 antibodies. These data demonstrate that the hFc gamma RI transgenic mouse model closely parallels the situation in humans. This mouse model seems useful for in vivo evaluation of the therapeutic potential of novel bispecific reagents in tumor and infection models.
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PMID:A human Fc gamma RI/CD64 transgenic model for in vivo analysis of (bispecific) antibody therapeutics. 858 68

In extensive preclinical testing, a CD3 x CD19 bispecific antibody (BsAb) induced killing of malignant B cells by resting T cells even in an autologous situation. In a 14 day clonogenic assay using a CD19+ pre-B cell line (REH), BsAb required repeated administration together with IL-2 to achieve a 5 log kill by resting peripheral blood T cells. Intravenously administered BsAb in an intrapatient dose escalation study of 3 patients with B cell non-Hodgkin's lymphoma showed limited toxicity (WHO grade II fever and chills) due to tumor necrosis factor-alpha (TNF-alpha) release by T cells. Pharmacokinetics with 2.5 mg BsAb showed peak levels of 200-300 micrograms/ml and a t1/2 of 10.5 h. The next patient, with chronic lymphocytic leukemia (CLL), received 0.6 mg BsAb/m2 as an i.v. infusion preceded by 1 MU IL-2/m2 s.c. Improved T cell activation was noted, as indicated by an increase in IFN-gamma, IL-6, IL-8, and IL-10, in addition to high TNF-alpha increases. TNF-alpha increases were highest on the first day. Toxicity remained restricted to grade II fever and chills, observed every day after the infusion of BsAb. No clear clinical effects were seen in this chemotherapy-resistant CLL patient with a high tumor burden. If subsequent patients also show limited toxicity, treatment of patients with a lower tumor load seems to be warranted to evaluate the efficacy of CD3 x CD19 BsAb therapy.
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PMID:Clinical experience with CD3 x CD19 bispecific antibodies in patients with B cell malignancies. 858 81

Production of high levels of granulocyte-macrophage CSF (GM-CSF) by LLC-LN7 tumors results in myelopoietic stimulation and an increase in cells having natural suppressor (NS) activity. Prior studies showed these NS cells could be isolated from the bone marrow of tumor-bearing mice with an Ab (ER-MP12) that recognized GM-progenitor cells. The present study showed these cells to also be in the spleen, lymph node, and tumor, and that treatment of tumor-bearing mice with low doses of IFN-gamma plus TNF-alpha reduced the frequency of E-MP12+ cells. Studies focused on characterizing the intratumoral ER-MP12+ cells and the mechanism by which they suppress T cell proliferation. When isolated and seeded in soft agar with CSF-containing LLC-LN7 supernatants, the ER-MP12+ cells grew into colonies, most of which contained both granulocytic and monocytic cells. Tumor-derived ER-MP12+ cells and their culture supernatants were suppressive to T cell proliferation. Among the factors produced by ER-MP12+ cells were TGF-beta, nitric oxide (NO), IL-10, and prostaglandin E2 (PGE2). However, it was TGF-beta and NO that mediated the suppression of T cell proliferation by ER-MP12+ cells. Intratumoral ER-MP12+ cells could be maintained as suppressive blastlike cells for at least 4 days in cultures containing CSFs, but adding IFN-gamma plus TNF-alpha to these cultures caused their differentiation mainly into nonsuppressive TNF-alpha-secreting monocytic cells. These results show that intratumoral ER-MP12+ cells having homology to GM-progenitor cells suppress T cell function by producing TGF-beta and NO. IFN-gamma/TNF-alpha treatment stimulates their differentiation and shift from production of TGF-beta and NO to production of TNF-alpha.
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PMID:Suppression of T cell proliferation by tumor-induced granulocyte-macrophage progenitor cells producing transforming growth factor-beta and nitric oxide. 859 44

In previous reports, we showed that tumor-derived TGF-beta induced overproduction of IL-10, and these suppressive cytokines caused macrophage suppression in EL4-bearing mice. Proliferation of T cells from EL-4, but not IL-2, whereas T cells from normal mice were responsive to IL-2. A balance between Th1- and Th2-type cytokine production in EL4-T in response to anti-CD3 Ab or phorbor myristate acetate plus A23187 shifted toward the Th2 dominant pattern. The prevention of TGF-beta and IL-10 activates in vivo by administration of anti-IL-10 Ab (anti-IL-10) or anti TGF-beta Ab (anti-TGF-beta) resulted in the reduction in EL4-T of both IL-4 dependent proliferation and Th2-dominant cytokine production induced by anti-CD-3 stimulation. In addition, the anti-TGF-beta treatment resulted in complete restoration in EL4-T of suppressed IL-2 responsiveness, IL-2R expression, and Th1-type cytokine production, whereas the anti-IL-10 treatment produced partial recovery. These results lead us to conclude that TGF-beta drives the shift in the Th1/Th2 balance toward Th2 via IL-10-mediated development of the Th2 responses and via inhibition of the Th1-type responses directly in EL4-bearing mice.
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PMID:TGF-beta contributes to the shift toward Th2-type responses through direct and IL-10-mediated pathways in tumor-bearing mice. 859 96

We investigated the cellular induction mechanism of antigen-nonspecific CD8+ T suppressor cells which suppressed delayed-type hypersensitivity to sheep red blood cells, by treating BALB/c mice with 7,12-dimethylbenz[a]anthracene (DMBA), a tumor initiator, and 12-O-tetradecanoylphorbol 13-acetate (TPA), a tumor promoter. Macrophages were activated by painting with 400 nmol of DMBA on mice. And the macrophages plus TPA induced CD4+ T suppressor inducer cells in the mice spleens. These cells were efficient at inducing CD8+ T suppressor-effector cells. When 8 nmol of TPA was painted daily on mice for 3 days following the treatment with 400 nmol of DMBA, or when spleen cells from mice pretreated with 400 nmol of DMBA were cultured in 32 nmol/5 ml of TPA for 3 days, inducer cells were formed in the spleen. Both T suppressor-inducer cells and macrophages from mice treated with DMBA were shown to act with the formation of soluble factors, which may be different from IL-10.
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PMID:Cellular induction mechanism of CD8+ suppressor T cells by DMBA and TPA: formation of CD4+ suppressor-inducer T cells. 860 30

2-Carboxyethylgermanium sesquioxide (Ge-132), a synthesized organogermanium compound with immunomodulating activities, was shown to be an inducer of anti-suppressor T cells in normal mice. The suppressor cell activity of T6S cells, a clone of burn-induced CD8+ IL-4-producing suppressor T cells, was clearly inhibited when a mixed lymphocyte-tumor cell reaction of the clone was conducted with splenic mononuclear cells from mice treated orally with a 100 mg/kg dose of Ge-132. The activity of anit-suppressor cells was demonstrated in spleens of mice 2 days after treatment with Ge-132 and reached its peak on day 3. The anti-suppressor cells induced by the compound were of a contrasuppressor T cell-linage, because they were characterized as CD4+ CD28+ TCRalpha/beta+ Vicia villosa lectin-adherent T cells. These cells produced IFN-gamma but did not produce IL-2, IL-4, IL-6 or IL-10 in their culture fluids. CD4+ anti-suppressor T cells induced by Ge-132 may be different from other subsets of CD4+ T cells because Th1 and Th2 cells generated in our laboratory did not adhere to Vicia villosa lectin-coated petri dishes, and each produced specific cytokines. Th1 cells produced IFN-gamma and IL-2 while Th2 cells produce IL-4 and IL-10 in vitro. These results suggest that Ge-132 may be useful as an inducer of contrasuppressor T cells in immunocompromised individuals bearing suppressor T cells. To eliminate suppressor T cells from immunocompromised hosts may result in improved resistance from various opportunistic infections.
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PMID:2-Carboxyethylgermanium sesquioxide, a synthetic organogermanium compound, as an inducer of contrasuppressor T cells. 860 18

Tumor cells of Epstein-Barr virus (EBV)-associated Hodgkin's disease (HD) express the viral protein, latent infection membrane protein-1 (LMP1), but evade cytotoxic responses normally directed at this antigen. We tested whether local production of the immunoregulatory interleukins (IL)-4 and -10 may have a role in this process. IL-4 RNA was not detectable in any of the HD cases. By contrast, isotopic in situ hybridization and correlation with the presence of EBV gene products showed significantly higher proportions of cases with IL-10 expressing tumor cells in LMP1-positive (17 of 26, 66%) as compared with LMP1-negative HD cases (six of 37, 16%). Absence of EBV BCRF1 RNA indicated that the transcripts originated from the cellular IL-10 gene. Similarly, an association between IL-10 expression and EBV-infection of tumor cells was found in AIDS-related malignant non-Hodgkin lymphomas (ARL). Very small proportions of EBV-infected cells, mainly blasts, expressed IL-10 in infectious mononucleosis tonsils. Thus, although not entirely exclusive to EBV-positive cases, IL-10 expression is frequently associated with EBV-infection in HD and ARL and appears to be upregulated by EBV, most likely through LMP1. In view of the established inhibitory effects of IL-10 on cell mediated immunity, it is suggested that IL-10 expression may contribute to evasion of LMP1-positive cells from cytotoxicity directed at viral antigens.
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PMID:Frequent expression of interleukin-10 by Epstein-Barr virus-harboring tumor cells of Hodgkin's disease. 863 12

IL-10 mRNA expression and protein production in established melanoma cell lines and freshly cultured primary and metastatic melanoma cells was examined. The in situ distribution of IL-10 in native melanoma tissue was also investigated by immunohistochemistry in primary tumors, metastases, benign melanocytic nevi and normal skin of healthy persons and melanoma patients. IL-10 mRNA, but not IL-10 protein in the culture supernatant, was found in 1 of 4 cultured melanoma cells of primary tumors, while 3 of 6 melanoma-metastasis-derived cultures expressed both IL-10 mRNA and protein. No IL-10 was detected in skin biopsies of healthy volunteers or in the healthy skin of melanoma patients; nor was IL-10 found in congenital melanocytic nevi. In only 1 of the 11 examined primary malignant melanomas was IL-10 immunoreactivity detected within the cytoplasm of cells in the tumor. On the other hand, 4 of 9 metastases clearly displayed scattered IL-1O+ cells. In all sections with IL-10-positive cells, the cells were positive for HMB-45. No co-expression of CD3 and IL-10 was observed. The data suggest that melanoma cells themselves are the main origin of IL-10 in tumor specimens in vivo. The preferential expression of IL-10 in metastatic lesions and in cultured cells from metastases might indicate an increased spreading potential of IL-10-secreting melanoma-cell clones.
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PMID:Interleukin-10 production in malignant melanoma: preferential detection of IL-10-secreting tumor cells in metastatic lesions. 864 20

Cellular IL-10 (cIL-10), the collective term for human and murine IL-10, has both stimulatory and inhibitory effects on diverse cell types, including costimulation of T cell proliferation, chemoattraction of CD8+ T cells, and stimulation of lymphokine-activated killer cell activity. Human IL-10 (hIL-10) differs from its EBV homolog viral IL-10 (vIL-10) by only 16% at the amino acid level; however, vIL-10 shares with cIL-10 predominantly inhibitory effects, such as macrophage deactivation. We administered cIL-10 systemically to mice bearing established (day 7) sarcomas, melanomas, or colorectal carcinomas. At high doses (20 to 60 micrograms/day x 7 days), cIL-10 induced rejection of tumors, delaying tumor outgrowth or resulting in complete cure. Sublethal irradiation (500 rad) of mice prior to tumor inoculation abrogated the IL-10 effect. Cured mice were immune to subsequent rechallenge with 10-fold higher inoculation with the same, but not a different, tumor. IL-12 also has potent antitumor activity and interacts with IL-10 in both complementary and antagonistic ways; co-administration of both cytokines resulted in additive antitumor activity. To compare cIL-10 vs vIL-10 effects in vivo, we engineered CL8-1 melanoma transfectants bearing the vIL-10 or the murine IL-10 (mIL-10) gene. Local secretion of mIL-10 induced rejection of tumors, while vIL-10 resulted in accelerated outgrowth. Subsequent systemic administration of cIL-10 to mice bearing vIL-10-transduced tumors completely reversed the local suppressive effects, leading to rejection, suggesting distinct pathways for cIL-10 and vIL-10 effects. That cIL-10 can stimulate the acquisition of an effective, specific, and long-lived antitumor immune response in murine models and can reverse the local immunosuppressive effects of vIL-10 indicates a potential role for cIL-10 administration in the biologic therapy of cancer and suggests a broader interpretation of IL-10 biology.
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PMID:Systemic administration of cellular IL-10 induces an effective, specific, and long-lived immune response against established tumors in mice. 868 20

We and others have previously found that splenic B cells from plasma cell tumor-bearing mice exhibit decreased CD23 expression. In the present study we further examined the mechanism of CD23 down-regulation by plasma cell tumors. We show here that although direct contact is required between the tumor cells and B cells, it is not sufficient, since fixed tumor cells do not induce the same reduction in CD23 expression. We have identified IL-10, a cytokine produce by the tumors, as the sole soluble factor that contributes to decreased CD23 expression on B cells induced by plasma cell tumors because 1) Abs to IL-10 prevent the loss of CD23 induced by plasma cell tumors both in vitro and in vivo; 2) engineered IL-10 negative variants of these tumors are reduced in their ability to down-regulate CD23 expression; 3) rIL-10 alone induces partial, but significant, decreases in CD23 expression on normal splenic B cells; and 4) the addition of IL-10 and fixed tumor cells to cultures of normal splenocytes decreases CD23 expression to levels similar to those in cocultures with live tumor cells. Collectively, these results demonstrate that plasma cell tumors down-regulate CD23 expression on B cells by a coordinate mechanism of IL-10 plus contact-mediated events and reveal a novel role for IL-10 in the regulation of CD23 expression on B cells that is suggestive of host B cell activation in the presence of the tumor.
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PMID:A combination of IL-10 and direct contact with plasma cell tumors decreases CD23 expression on splenic B cells. 869 Sep 1


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