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

Multicellular spheroids of EMT6 mammary sarcoma cells of BALB/c origin were incubated with normal spleen cells or alloimmune spleen cells generated in vitro in mixed leukocyte cultures (MLC). After 24 hours, spheroids were trypsinized and assayed for surviving tumor cells by use of a cloning technique. Under these conditions a 60-80% reduction in clone-forming tumor cells was observed after incubation of spheroids with immune lymphocytes as compared to normal lymphocyte controls. This cytotoxic effect occurred in situ, and alloimmune cells sensitized against unrelated antigens were much less cytotoxic than were specifically sensitized cells. In parallel autoradiographic studies, some immune lymphoid cells that had been labeled with tritiated thymidine during the proliferative phase of the MLC could be demonstrated within spheroids after 24 hours. These results suggested that multicellular spheroids will be a useful in vitro model for more detailed analysis of the factors controlling infiltration in in situ destruction of solid tumor grafts.
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PMID:Multicellular spheroids: a new model target for in vitro studies of immunity to solid tumor allografts. 14 Sep 43

Effects of the methanol extraction residue (MER) fraction of tubercle bacilli (BCG) on the generation of cytotoxic lymphoid cells were studied in vitro with the use of unidirectional mixed lymphocyte-tumor cell cultures. These cultures consisted of splenocytes of lymph node cells from normal donor C57BL/6, BALB/c, and strain A mice and mitomycin C-inactivated leukemia cells of both syngeneic and allogeneic origin. Addition of small amounts of MER (0.2-5 microgram/ml) to the cultures potentiated appreciably the elicitation of cytotoxic reactivity (as measured by the 51Cr-release assay) of the sensitized cells, whereas higher quantities (10-40 microgram/ml) had a strong suppressive effect. MER also induced some cytotoxic capacity in normal murine and human lymphoid cells not exposed to specific tumor cell stimulation. The stimulatory and suppressive effects were noted only when MER was present during the initial 24-48 hours of the 6-day culture. With the nylon wool fractionation technique, it was apparent that MER affected primarily the nonadherent cell population. MER could also prevent the generation of nonspecific suppressor cells by splenocytes maintained for 3-6 days in tissue culture.
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PMID:In vitro induction of cell-mediated immunity to murine leukemia cells. III. Effect of methanol extraction residue fraction of BCG on the generation of cytotoxic lymphocytes against leukemia. 14 48

We have analyzed the impact of in vivo administration of Corynebacterium parvum on the mouse immune system against murine tumors, using the natural cytotoxic ability against tumors of normal mouse lymphoid cells as a baseline. A striking difference was found depending on the route of administration. Intravenous inoculation of bacteria would result in a significant decrease or sometimes complete abolition of natural cytotoxicity toward tumor cells of the spleen cells of treated mice. On the other hand, the intraperitoneal route of administration resulted in a dramatic increase in cytolytic ability of the peritoneal exudate cells. Both routes of treatment had the most significant impacts on the local cell population (IV = spleen, IP = peritoneal exudate cells) with only minor effects on other cell populations. Analysis of the spleen cell population from IV-treated mice did also demonstrate a significant reduction in the T lymphocyte function, but in contrast to the natural cytotoxicity this could be corrected for by the removal of suppressor cells of an adherent nature. The lytic cells induced in the peritoneal exudate by the Corynebacterium parvum bacteria were all found to be natural killer, NK, cells with no significant activity found amongst macrophages using short-term cytolytic assays.
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PMID:An analysis of conditions allowing Corynebacterium parvum to cause either augmentation or inhibition of natural killer cell activity against tumor cells in mice. 14 72

Mice have been immunosuppressed with cyclophosphamide, cortisone-acetate, irradiation, or Ehrlich ascitic fluid (EAF) and then grafted with Ehrlich tumor or with one of the following strain-specific tumors: thymoma, methylcholanthrene-induced fibrosarcoma, B-16 melanoma, lymphatic leukaemia, and myeloid leukaemia. Immunosuppression of the host influenced very differently the growth of transplanted malignancies. The growth of thymoma and of Ehrlich tumor was regularly enhanced. The growth of fibrosarcoma and of melanoma, on the other hand, was retarded in mice pretreated with EAF and X-rays, or remained unchanged in mice pretreated with drugs. Leukaemia growth was not influenced by any immunosuppressive treatment; the only exception was enhanced growth of lymphoid leukaemia in animals pretreated with EAF. Thus different tumors grew differently in animals immunosuppressed by the same immunosuppressive agent, while different immunosuppressive treatment changed the growth of one particular tumor always in the same way. From this we concluded: (1) there is no rule as to how immunosuppression of the host will influence tumor growth; and (2) the way in which the malignant growth will be changed depends mainly upon the type of the tumor and probably not very much upon the type of immunosuppressive treatment.
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PMID:Effect of immunosuppression on the growth of six murine tumors. 15 96

Peripheral blood lymphocytes from Minnesota miniature pigs were tested for natural killing (NK) and antibody-dependent cellular cytotoxicity (ADCC) in a 2- to 4-hr 51Cr release assay against human myeloid and lymphoid tumor target cells. Adult specific pathogen-free and germfree animals exhibited normal levels of activity in both assays. In addition, the NK and ADCC activities of peripheral blood lymphocytes from colostrum-deprived newborn piglets were examined. These animals were obtained by hysterectomy and previously shown to be immunologically "virgin." We found that these newborn piglets exhibited normal ADCC but lacked NK activity. The differences in the ontogeny of the two activities suggest that they are distinct. Preliminary effector cell characterization studies suggest that: (i) NK and ADCC in the pig are physically not separable; (ii) the majority of the cytotoxic activity on a cell-per-cell basis is mediated by the non-T lymphocyte fraction; and (iii) the rosetted T cells, which account for about 60% of the total pig peripheral blood lymphocytes, have low but demonstrable cytotoxic activity as well.
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PMID:Natural killing and antibody-dependent cellular cytotoxicity are independent immune functions in the Minnesota miniature swine. 15 4

The effect of specific priming with alloantigens on the frequency of cytolytic T lymphocyte precursors (CTL-P) has been investigated. Alloimmune lymphoid cells were obtained from the spleen of C57BL/6 (H-2b) mice primed with DBA/2 (H-2d) tumor cells or from 14-day unidirectional mixed leukocyte cultures (C57BL/6 anti-DBA/2). CTL-P frequencies directed against H-2d alloantigens were estimated by limiting dilution analysis in a sensitive micro MLC system. Under these conditions, an apparent increase of 3 to 4-fold in CTL-P frequency was observed in alloimmune (as compared with normal) C57BL/6 spleen cells. Evidence was obtained suggesting that this increase was specific for the priming alloantigens. A much greater increase in CTL-P frequency (25 to 100-fold) was observed after alloimmunization of C57BL/6 spleen cells in unidirectional MLC. Under the latter conditions, 5 to 20% of the surviving splenic MLC cells could be identified operationally as CTL-P. A similar enrichment in CTL-P frequency was obtained when lymph node, peripheral blood, or thymus cells were cultured for 14 days in MLC. These studies provide direct evidence that the pool of specific CTL-P can be expanded after alloimmunization. Furthermore, the very high frequencies observed after in vitro priming indicate that this system should be particularly useful for future studies of the progeny of individual CTL-P.
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PMID:Limiting dilution analysis of alloantigen-reactive T lymphocytes. III. Effect of priming on precursor frequencies. 15 30

It is now well recognized that a large proportion of cases with acute lymphoblastic leukemia are classified as non-T/non-B neoplastic disease. The origin of leukemic non-T/non-B cells is at present not known. It has been shown that fresh or cultured leukemic T lymphoblasts exert no stimulating capacity while leukemic B lymphoblasts exert a strong stimulation in "one-way" mixed lymphocyte reaction. It has also been shown that fresh leukemic cells from some patients with non-T/non-B acute lymphoblastic leukemia possess a strong stimulation while leukemic cells from other patients with this disease possess no stimulation on allogeneic lymphocytes. The present study shows that cultured leukemic lymphoblasts from 3 non-T/non-B cell lines (NALL-1, NALM-6 and NALM-16) consistently exert a strong stimulation on allogeneic lymphocytes. On the other hand, cultured leukemic lymphoblasts from 2 non-T/non-B cell lines (REH and KM-3) consistently fail to stimulate in "one-way" mixed lymphocyte reaction. Our data clearly support the speculation that leukemic non-T/non-B cells which possess the stimulating capacity may represent less differentiated leukemic B lymphoid cells (pre-B cells) and leukemic non-T/non-B cells which possess no stimulating capacity may represent less differentiated leukemic T lymphoid cells (per-T cells).
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PMID:Cultured human leukemic non-T/non-B lymphoblasts and their stimulating capacity in "one-way" mixed lymphocyte reaction: suggestive evidence for early T-cell or B-cell precursors. 15 81

Spleen cells from mice treated with cyclophosphamide (100 to 200 mg/kg) were unable to generate effective cytotoxic thymus-derived cells to allogeneic tumor cells in vitro. The inability of lymphoid cells from cyclophosphamide-treated mice to generate thymus-derived cytotoxic cells became more apparent as the number of responding cells became limited. This depressed response was not due to the elimination of cytotoxic precursor cells since normal response levels were restored by the addition of thymus cells. The added thymus cells did not provide cytotoxic cells in the culture. The thymus cells active in restoring cytotoxic activity were sensitive to mitomycin C, cyclophosphamide, and anti-theta serum and complement. In addition, the active thymus cells were located in the cortisone-resistant pool and did not adhere to nylon wool columns.
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PMID:Restoration of cyclophosphamide-induced suppression of thymus-derived cytotoxic cell generation by normal thymocytes. 15 6

1) The in vitro effect of virus-inhibiting factor (IF) or interferon on Ehrlich ascites tumor and sarcoma 180 was found to be cytostatic, but not cytocidal. 2) Mouse peritoneal macrophages or splenic lymphoid cells, in the presence of IF, did not affect multiplication of the tumor cells examined.
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PMID:[Effects of the virus-inhibiting factor or interferon on the in vitro multiplication of mouse tumor cells]. 15 14

Specific cell-mediated immunity to SV 40 tumor-specific transplantation antigen (TSTA) in mice undergoing tumorigenesis by syngeneic SV 40-transformed BALB/C cells was investigated by the macrophage migration inhibition (MMI) and transplantation rejection tests. Specific cellular reactivity to SV40 TSTA could be demonstrated in BALB/c mice early after tumor cell inoculation. This activity was no longer detectable during the later stages of tumor growth but was again demonstrable 2 weeks after tumor excision. Addition of an equal number of non-reactive peritoneal exudate (PE) cells from tumor-bearing mice to PE cells from mice immune to SV40 TSTA specifically abrogated the reactivity of the latter cells to soluble SV40 TSTA. When lymphoid cells with blocking activity were cultured in vitro they not only lost their blocking capacity but also regained their reactivity to SV40 TSTA in the MMI test. These findings indicate that tumor-bearing hosts possess lymphocytes specifically sensitized to the TSTA of the tumor and that the specific reactivity of these cells can be regained after culture in vitro.
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PMID:In vitro studies on the cellular immune response of tumor-bearing mice to SV40-transformed cells. 16 78


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