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

Tumor-specific T-cell clones were derived from spleen cells of mice bearing a syngeneic PHS-5 tumor (a P815 mastocytoma mutant). Cells were expanded in vitro and characterized and assayed for activity against the relevant tumor in vivo. Clone cells were CD4-, CD8+ T lymphocytes, as determined by fluorescence activated cell sorting analysis and were specifically cytotoxic against P815 tumor cells in vitro, as shown in chromium 51 release assays. These cells require both antigen and interleukin 2 to proliferate; neither alone is sufficient, even with the addition of interleukin 1. In an experimental P815 liver metastasis model, the adoptive transfer of GD11 or GD11.17 clone cells and injection of recombinant interleukin 2 (7500 U intraperitoneally) 3 days after infusion of tumor cells reduced the number of tumor nodules, while the adoptive transfer of lymphokine-activated killer cells was ineffective.
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PMID:A cytotoxic T-lymphocyte clone derived from mice with progressively growing tumors. 167 91

CD4+ and CD8+ T cells do not develop significant lymphokine-activated killer (LAK) activity when PBL are cultured with IL-2 or even when they are activated with a T cell stimulus such as OKT3 mAb. The possibility that a T cell regulatory mechanism prevents the development of LAK activity by CD4+ or CD8+ cells in OKT3 mAb and IL-2 cultures was tested by depleting CD8+ or CD4+ cells from PBL before stimulation with OKT3 and IL-2. Under these conditions, the remaining CD4+ and CD8+ cells were able to generate non-MHC-restricted lysis of NK-resistant tumor targets. Our data suggested that a regulatory signal was present in the culture to prevent the development of lytic function by T cells. T cells removed from the PBL cultures were, upon culture with IL-2, able to generate high LAK activity, suggesting that inhibition of the CD4+ or CD8+ T cell-mediated LAK activity was an active ongoing process, which blocked the lysis at the level of the activated cell and not the precursor cell. Mixing experiments demonstrated that the CD4+ or the CD8+ cells isolated from the PBL cultures were able to inhibit the development of lytic function in the CD4-depleted and CD8-depleted cultures. Transforming growth factor-beta (TGF-beta) has been shown to block LAK activity of NK cells in IL-2-stimulated cultures. When TGF-beta was added to CD4(+)- or CD8(+)-depleted cultures, it also inhibited LAK activity of T cells in a dose-dependent fashion, without interfering with T cell growth. Lytic activity returned to activated levels when TGF-beta was removed from the culture medium, thereby demonstrating the reversibility of TGF-beta inhibition.
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PMID:Generation of lymphokine-activated killer activity in T cells. Possible regulatory circuits. 167 80

To investigate whether the retargeting of resting CTL can benefit from cooperative signaling between the TCR/CD3 complex and various accessory molecules, such as CD2, CD4, CD5, and CD8, we have constructed a series of trispecific F(ab')3 derivatives. Each derivative was designed to engage effector T lymphocytes with two Fab' arms, and tumor cells with a single Fab' arm. They were constructed by selective coupling of three mAb Fab' fragments, primarily via their hinge-region sulfhydryl groups, using the cross-linker o-phenylenedimaleimide. En route to the production of trispecific F(ab')3 antibodies a range of bispecific F(ab')2 derivatives was first prepared which could bind simultaneously to two different receptor molecules on T cells. Bispecific derivatives containing specificities for (CD2 (T11(1)) x CD3), (CD3 x CD4), (CD3 x CD8) or two epitopes on CD2, ((T11(1) x (T11(3)), all yielded two to three times the uptake of [3H]thymidine with fresh PBMC to that seen with intact IgG from anti-CD3 (OKT3). The exception to these findings was a bispecific F(ab')2 derivative with specificities for (CD3 x CD5) which caused slightly less proliferation than the control reagent, OKT3 IgG. When these bispecific antibodies were converted into trispecific antibodies (TsAb) by the addition of a Fab' from anti-CD37 they were then all able to retarget resting, unprimed, T cells from fresh PBMC for lysis of CD37+ tumor cells. However, the cytotoxic activity of these reagents fell into two distinct groups: group one, containing (anti-CD3 x anti-CD4 x anti-CD37), (anti-CD3 x anti-CD5 x anti-CD37), and (anti-CD3 x anti-CD8 x anti-CD37), gave minimal lysis and behaved in a similar way to the BsAb, (anti-CD3 x anti-CD37), i.e., no evidence of cooperative signaling for lysis; and group two, containing (anti-T11(1) x anti-CD3 x anti-CD37) and (anti-T11(1) x anti-T11(3) x anti-CD37), which were highly cytotoxic and gave up to 80% specific 51Cr-release. The failure of group one TsAb, in particular (anti-CD3 x anti-CD8 x anti-CD37) which should recruit CD8+ CTL, to give efficient lysis despite having anti-T cell arms that were mitogenic as a bispecific antibody, indicates that the cooperative signaling for proliferation is probably distinct from the signal(s) provided by group two TsAb that activate for both proliferation and lysis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Trispecific F(ab')3 derivatives that use cooperative signaling via the TCR/CD3 complex and CD2 to activate and redirect resting cytotoxic T cells. 167 55

Distinct changes in the antigenic phenotypes of mononuclear cells infiltrating primary and metastatic malignant melanomas (MM) have been shown to characterize distinct steps of melanoma progression. The purpose of our study is to establish whether the growth fraction of malignant melanoma cells is related to the mononuclear cell subtypes. Using monoclonal antibody Ki67, the presence of a nuclear antigen in proliferating cells of both tumor and inflammatory infiltrate cells was established in 20 primary recurrent and metastatic cutaneous melanomas. Monoclonal antibodies against lymphocyte and macrophage subsets were also applied in situ. Numerous CD8 and CD4 positive cells and natural killer (NK) cells were detected in all the infiltrates. A low CD4+/CD8+ ratio was observed in most tumors with a high proliferative activity. The presence of positive CD1+ cells seemed also to be correlated with a high activity. Our data suggest a correlation between inflammatory cell subsets and proliferative activity of MM.
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PMID:Characterization of proliferative cells in malignant melanomas and their inflammatory infiltrates. 167 44

To generate autologous-tumor-specific cytotoxic T cells (CTL), peripheral blood mononuclear cells (PBMC) obtained from cancer patients were cultivated with autologous tumor cells for 5 days, and restimulated with interleukin-2 for another 5 days. Subsequently, their cytotoxic activity was examined by an in vitro cytotoxic test as well as by Winn's assay utilizing nude mouse transplanted autologous tumors. The present results demonstrated that these in vitro-stimulated cells were able to kill autologous tumor cells but not allogeneic tumors, and that they also inhibited the growth of transplanted autologous tumors in the nude mouse. Their cytotoxic activity was completely abrogated by pre-treatment with either anti-CD3 or anti-CD8, but not with anti-CD4, plus complement. Based on these studies, we injected these CTL via the hepatic artery into patients having either nonresected tumors or recurrent tumors in the liver. Among 15 treated patients (13 with hepatocellular carcinoma and 2 with metastatic liver cancer) 2 complete responses, 3 partial responses and 4 minor responses were observed. During the 6 to 25 months following injection of CTL, no definite signs of tumor recurrence or regrowth were demonstrated in these 5 responding patients (complete plus partial).
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PMID:Induction of autologous tumor-specific cytotoxic T cells in patients with liver cancer. Characterizations and clinical utilization. 167 33

Twelve autologous mixed peripheral blood (PBL) tumor cell interactions (MLTC) followed by in vitro expansion of the stimulated T cells in recombinant interleukin-2 (IL-2) were analyzed for the potential emergence of oligoclonal or monoclonal T cell populations in the PBL by Southern blot analysis of the T cell receptor (TCR) beta gene. The emergence of oligoclonal or monoclonal TCR beta gene rearranged populations was seen in 5 of the 12 cases. In 2 of these 5 cases only one dominantly rearranged band was observed. The emergence of oligoclonal or monoclonal T cell populations following stimulation with autologous melanoma cells was associated with predominant CD4 phenotype of the stimulated PBL exhibiting a varied degree of cytotoxicity toward the respective autologous melanoma cells. The evidence of emergence of monoclonal or oligoclonal T cell populations following stimulation with autologous tumor cells strongly supports the existence of T cell-mediated responses against autologous melanomas. Furthermore, cellular and molecular analyses of T cell responses in autologous mixed lymphocyte tumor cell interactions will provide valuable information on the nature of the T cell responses and on the pattern of gene segment usages by the T cells in response to the autologous tumor cells.
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PMID:Clonal expansion of T cells following in vitro stimulation with autologous melanoma cells and interleukin-2 studied by molecular analysis of a T cell receptor. 167 14

There has been much speculation as to the role of Langerhans cells (LC) in the induction of anti-tumor immunity. Whereas there is considerable circumstantial evidence that disruptions in the density and function of these cells during the early stages of ultraviolet (UV) light- and chemical carcinogen-induced carcinogenesis may be important for enabling developing neoplasms to escape immune destruction, the role of the large number of these cells found infiltrating developed skin tumors is less clear. To investigate this we have compared the LC density infiltrating transplanted non-immunogenic and immunogenic UV-induced murine tumors as well as LC in the epidermis overlying the tumors. Whereas two non-immunogenic tumor lines attracted large numbers of Ia+ dendritic cells, an immunogenic tumor line did not. Similar results were obtained whether the tumors were transplanted into syngeneic immunocompetent or athymic immunodeficient mice. Hence, there was no relationship between tumor immunogenicity or host immunocompetence and Ia+ dendritic cell density. Furthermore, there was no correlation with the pattern of T-cell infiltration of the tumors or CD4/CD8 cell ratio. Our results also indicate that whereas UV light decreased Ia+ cell density, both in the epidermis and the tumors, it did not inhibit the tumors from attracting Ia+ dendritic cells. Thus, the Ia+ dendritic cells infiltrating skin tumors are unlikely to indicate a host immune response to the tumor, but are more likely to be attracted by tumor-derived cytokines.
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PMID:Langerhans cell migration into ultraviolet light-induced squamous skin tumors is unrelated to anti-tumor immunity. 168 Sep 31

A novel cytotoxicity, which is normally hidden but unveiled upon interacting with heat-shocked tumor target, has been identified in CD4+ Th1 cells. When TNF-resistant, Ag-presenting tumor targets were heat shocked, the cytotoxicity by specific Th1 clones was significantly enhanced. Interestingly, the DNA of heat-shocked, unpulsed targets including Ia- tumor cells were also fragmented by Th1 clones. In contrast to the Ag-dependent, MHC-restricted cytotoxicity, the heat-shock-induced sensitivity to Th1 clones was a) Ag independent and MHC unrestricted, b) insensitive to CD4-mAb, c) resistant to actinomycin D and cycloheximide, and d) greatly enhanced by cholera toxin, PGE1, PGE2, and dibutyryl cAMP. This novel cytotoxicity was inhibited by mAb specific to lymphocyte function-associated Ag-1 and intercellular adhesion molecule-1. Upon culturing at 37 degrees C, mildly heat-shocked target cells gradually recovered, indicating that the heat-shock-induced sensitivity was transient and reversible. The implication of this study for a signal-induced internal disintegration mechanism for target death is discussed. The novel cytotoxicity of CD4+ Th1 cells may be an important mechanism of immune regulation under febrile conditions and an underlying mechanism for the hyperthermia treatment of cancers.
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PMID:A novel cytotoxicity of CD4+ Th1 clones on heat-shocked tumor targets. I. Implications for internal disintegration model for target death and hyperthermia treatment of cancers. 168 89

A high-cloning efficiency, filler cell-free limit-dilution culture system for the growth and differentiation of single cytotoxic T lymphocyte precursors (CTLp) was tested for its ability to maintain the lytic specificity of the resultant clones of cytotoxic T lymphocytes (CTL). The system used non-specific stimulation with phorbyl ester and calcium ionophore, maintenance of growth over the first 6 days of culture with interleukin (IL)-2 and interferon-gamma, and maintenance of growth and differentiation over the last 2 days of culture with IL-2 and IL-6. Under these defined conditions around 50% of all CD4- 8+ T cells developed into CTL clones that were specific in their lytic activity. In contrast, a culture system maintained by irradiated filler cells showed non-specific lysis of both YAC-1 type natural killer targets and of P815 type targets, while a culture system maintained by IL-2 and a crude growth factor preparation showed non-specific lysis of natural killer targets but not of P815. The defined lymphokine culture system was suitable for determining the specificity repertoire of primary CTLp. Using this system, the frequency of reactivity with allogenic tumor targets was found to be approximately one CTLp in 30 for several mouse strain/target cell combinations.
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PMID:The maintenance of lytic specificity during the development of clones of cytotoxic T lymphocytes from single precursor cells. 168 90

The monoclonal antibody (MAb), C5B6, recognizes the CD11c/CD18 molecule on the surface of bovine peripheral blood monocytes. C5B6 was reactive with 69-83% monocytes, all granulocytes, and less than 5% of lymphocytes from cattle. Of the lymphocyte series, the antibody had specificity for large lymphocytes and two lines expressing T cell markers, but was not reactive with small lymphocytes, thymocytes, a tumor cell line of B-cell lineage, an interleukin 2 (IL2)-dependent T cell line, fibroblasts, or human, sheep, goat or pig peripheral blood mononuclear cells. No dual fluorescence was seen using C5B6 and antibodies to bovine IgM, CD2, CD4 or CD8. Immunoprecipitation of 125I labeled peripheral blood mononuclear cells with C5B6 antibody defined two bands: 150,000 and 95,000 Da. Antibody to the beta chain (CD18) of the leukocyte adhesion receptor family precipitates the 95 kDa beta subunit and the three associated alpha subunits (180, 165 and 150). The bands obtained using MAb C5B6 correlated with the p150/95 bands observed using an antibody that precipitated the alpha and beta chains of the leukocyte adhesion receptor family. Functionally, the primary but not the secondary proliferative response to alloantigens was inhibited by C5B6 MAb. No effect was seen using C5B6 MAb in cytotoxicity assays or in the secondary proliferative response to Brucella abortus or bovine herpes virus type 1.
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PMID:The bovine p150/95 molecule (CD11c/CD18) functions in primary cell-cell interaction. 168 51


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