Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interest in tumor immunology grew out of the study of host response to microbial infections during the second half of the 19th century. However, the growth of interest in transplantation during the 1950s and 1960s is largely responsible for the great surge of scientific investigation into tumor immunobiology which we are experiencing today. Tumor cells possess certain abnormal antigens in addition to their normal complement of transplantation antigens. These abnormal antigens evoke an immune response in the host, which involves both the humoral and the cell-mediated systems. Though the cell-mediated (thymus derived) system is generally conceded the most important role in tumor cell destruction, the humoral (bursal-equivalent derived) system also plays a role in host response which is presently less clearly understood. Certain aspects of the humoral response (blocking factors) actually appear to inhibit the host response against a tumor. This complex system of host immune response to tumor has been termed the immunosurveillance system.
 ...
PMID:Current concepts of tumor immunology. I. Basic immunologic concepts. 7 72

Tumor-specific immunity mediated by thymus-derived lymphocytes (T cells) was established in C3H/He mice against syngeneic X5563 plasmacytoma. Splenic T cells from mice, which exhibited resistance to tumor challenge, revealed a potent in vivo tumor-neutralizing activity as well as in vitro cytotoxicity. In contrast, spleen cells from mice 7 days after tumor cell inoculation (7-day tumor-bearing mice) exhibited no protective activity when assayed by in vivo tumor-neutralization test, whereas these cells exhibited almost comparable in vitro cytotoxic activity to that from the tumor-resistant mice. Any suppressor cell activity was not detected in 7-day tumor-bearing animals. While a slight in vivo protective activity was observed in the spleen cells from 14-day tumor-bearing mice, this activity was still significantly weaker than that of spleen cells from mice similarly inoculated with tumor 14 days before but whose tumor had been removed 7 days before the assay. The development of in vivo protective immunity in tumor-resected mice was suppressed by intravenous inoculation with 7000 R X-irradiated tumor cells. These results indicate that in vitro reactivity of immune T lymphocyte population is not always correlated with in vivo protective immunity, but there is a substantial decrease in in vivo immune capability of T cells from tumor-bearing animals, and that this suppression may be ascribed to the presence of a large amount of tumor-associated transplantation antigens rather than to suppressor cell activity.
 ...
PMID:Inhibitory effect of tumor-bearing state on the generation of in vivo protective immune T cells in a syngeneic murine tumor system. 7 90

Lymphatic leukemia developed in C57BL/6 mice following inoculation of normal thymocytes that and been co-cultured on leukemic thymus epithelial reticulum monolayer cells. Using thymocytes genetically marked in Ly membrane antigens, we showed that the thymomas which developed were produced by the co-cultured thymocytes rather than by leukemic cells derived from the monolayer. Thus, leukemogenic conversion of normal thymocytes took place in vitro. Inoculation of cultured leukemic thymus epithelial reticulum monolayer cells (LTER) gave rise mainly to reticulum cell sarcomas and myeloid leukemias, rather than to lymphatic leukemias (which developed following inoculation of thymocytes that had been cultured on the LTER monolayers). Thus LTER cells may themselves be tumor cells capable of producing RCNA (reticulum cell neoplasm type A) or myeloid tumors in addition to their ability to convert normal thymocytes into leukemic cells.
 ...
PMID:Genetic analysis of in vitro leukemogenesis induced by thymus epithelial reticulum cells transmitting murine leukemia viruses. 7 90

Previous studies from this laboratory have mapped resistance and/or susceptibility to radiation-induced leukemia virus (RadLV)-induced neoplasia to the H-2D region. H-2 linked effects on virus replication can be detected subsequent to the initial virus infection, and clear-cut differences in numbers of virus infected thymus cells can be detected as early as 5 wk after RadLV inoculation. Rapid increases in cellular synthesis and cell surface expression of H-2 antigens are detectable immediately after virus inoculation. These changes have been studied by immunofluorescence, absorption, cell surface iodination followed by sodium dodecyl-sulfate-polyacrylamide gel electrophoresis, and two dimensional gel electrophoretic analysis of internally labeled lymphocyte proteins. Expression of H-2K molecules is significantly increased in cells of susceptible and resistant animals. However, significant increases in expression of H-2D antigens occurs only on thymus cells from resistant strains (H-2Dd). Transformed cells of resistant and susceptible H-2 haplotypes adapted to tissue culture lack detectable H-2 antigens as determined by serological absorption studies. It is argued that altered expression of H-2 antigens plays a very significant role in the mechanism of host defense to virus infection.
 ...
PMID:Increased synthesis and expression of H-2 antigens on thymocytes as a result of radiation leukemia virus infection: a possible mechanism for H-2 linked control of virus-induced neoplasia. 7 39

During each transplantation passage of a line of mouse myeloma tumor MOPC-315 through syngeneic (BALB/c) hosts, the tumor cells lose reactivity with cytotoxic thymus-derived lymphocytes directed against products of the BALB/c major histocompatibility complex (H-2d) and regain reactivity on transfer to fresh hosts. In contrast to this cyclical change, the tumor cells remain uniformly reactive with anti-H-2d alloantisera throughout the transplantation cycle.
 ...
PMID:Periodic loss of reactivity of a myeloma tumor with cytotoxic thymus-derived lymphocytes. 7 47

In an experimental model conditioning for enhancement, an AKR lymphoma was made to grow in BALB/c mice, permitting the simultaneous comparison of tumor-bearing (progressor) and tumor-rejecting (regressor) animals. By immunofluorescence using as target AKR lymphoma and normal thymus cells, both acetone-fixed and unfixed, it was observed that the allogeneic progressor serum contained three antibodies, two of which could be asborbed by thymocytes while the other combined selectively with the acetone-fixed lymphoma target. This tumor-specific antibody could not be detected in regressor serum which, on the other hand, could be completely absorbed by thymocytes. The identification of this acetone-resistant tumor antigen led to the preparation of aceton-treated acellular lymphoma extracts: a precipitate was obtained which upon inoculation in BALB/c mice produced an antiserum that combined selectively with lymphoma targets. In vivo experiments showed that pretreatment with this antigen led to a significant increase in allogeneic tumor incidence, 76% as compared to 37% in the controls. It is concluded that in this allogeneic model, an acetone-resistant tumor-specific antigen and the corresponding antibody are involved in tumor enhancement.
 ...
PMID:Antigenic differences between AKR lymphoma and thymus cells leading to detection of a tumor antigen associated with immunological enhancement. 7 15

Two DNA probes representative of either the entire mouse mammary tumor virus (MMTV) genome or the poly(A)-adjacent sequences at the 3' end of MMTV RNA were synthesized with calf thymus DNA or oligo(dT) primers, respectively. These probes were used to study the expression of endogenous MMTV sequences in several BALB/c mammary tumor cell lines, in normal lactating BALB/c tissue, and in a cloned C3H tumor cell line. Both probes were characterized with respect to their rates of hybridization with template RNA, their size as determined by alkaline sucrose gradient centrifugation, and the thermal stability of the cDNA.MMTV RNA hybrids. In addition, the ability of the calf thymus oligodeoxy-nucleotide- or oligo(dT)-primed probes to protect (125)I-labeled MMTV RNA or (125)I-labeled poly(A)-adjacent MMTV RNA sequences from S1 nuclease digestion was determined. Hybridization analysis with these two probes indicated that (i) there were approximately 20-fold more oligo(dT)-primed sequences in BALB/c lactating tissue than there were sequences representing the entire genome; (ii) in BALB/c tumor cells, the oligo(dT):random oligonucleotide-primed cDNA sequence ratio was reduced to 4:1; and (iii) in virus-producer C3H tumor cells, there was only a 2-fold excess of oligo(dT)-primed sequences over that observed with a representative cDNA. These results are consistent with the presence of subgenomic viral mRNA species, integration of partial proviral copies, or altered mRNA processing.
 ...
PMID:Differential expression of poly(A)-adjacent sequences of mammary tumor virus RNA in murine mammary cells. 8 48

beta 2-Microglobulin is a low molecular weight protein that is found in most biological fluids. It was originally isolated from urine of cadmium-poisoned patients. Its amino acid sequence was established and shown to be structurally related to immunoglobulin constant domains. With the aid of antibodies specific against beta 2-microglobulin, the protein was detected on the membranes of all nucleated cells, normal and neoplastic. Measuring the quantity of beta 2-microglobulin showed that high levels are present in patients with renal tubular deficiencies and several other pathological conditions including neoplastic diseases. Extremely high levels were detected in seminal fluid and colostrum. Despite the structural relationship to immunoglobulins, no immunological relationship was demonstrated with these proteins using antibodies specific for beta 2-microglobulin. However, such antibodies are cytotoxic to all cells carrying beta 2-microglobulin on their surfaces. The discovery that beta 2-microglobulin is an integral part of the histocompatibility antigens of human and murine origin stimulated further research and interest in this molecule. Several groups of investigators have shown that beta 2-microglobulin is the low molecular weight chain and is noncovalently bound to a high molecular weight chain which carries the histocompatibility antigens. The structure of the histocompatibility antigens of lymphocytes (HLA) was shown by immunochemical as well as biological methods, and it is now well accepted. The antibodies against beta 2-microglobulin are extremely useful in the isolation of the histocompatibility antigens for sequence studies. Furthermore, the antibody to beta 2-microglobulin revealed that other structures may be bound to beta 2-microglobulin such as phytohemoagglutimin (PHA) receptors, mixed lymphocyte culture (MLC) antigens, etc. Murine thymus leukemia (TL) antigen also contains beta 2-microglobulin as an integral part of its structure; other tumor antigens may have a similar structure. Through all these studies, beta 2-microglobulin emerged as the best known membrane protein that can serve as a model for study of the arrangement and the function of the cell membrane.
 ...
PMID:beta 2-Microglobulin: methods and clinical applications. 8 22

Sera from C3H/HeHa mice immunized with syngeneic methylcholanthrene-induced sarcoma react with allogeneic thymus, lymphoma and leukemia cells. The presence on leukemia and lymphoma cells of H-2 specificities expressed on normal cells of other H-2 haplotypes from the one in which the tumor originates is described. It was observed that the reaction of antisera to H-2 specificities with lymphoma cells was blocked by anti-MCA sarcoma sera. The cross-reactivity between MC sarcomas, thymus, leukemia and lymphoma cells is considered to be due to antibodies against these "alien" allospecificities.
 ...
PMID:Alien H-2 allospecificities in murine chemically-induced tumors. 9 37

Normal human lymphoid cells from peripheral blood, spleen, tonsils and thymus were examined for their ability to mediate three different cytotoxic effector cell functions: antibody-dependent cellular cytotoxicity (ADCC); lectin-induced cellular cytotoxicity (LICC) and natural killer activity (NK), against 51Cr labelled erythroid and tumor target cells. We found a hierarchy of cytotoxic activities in the different lymphoid tissues. Peripheral blood and spleen cells were able to mediate LICC, ADCC and NK activities. Tonsil cells showed a natural segregation of the different cytotoxic functions: NK and ADCC activity against tumor target cells were absent, whereas LICC activity was fully present. With respect to ADCC activity against erythroid targets, tonsil cells showed low, but significant, cytotoxicity. Thymus cells had no detectable ADCC, NK and LICC activities. Correlation in the different lymphoid tissues between cytotoxic activities and cell surface marker studies revealed: (a) that the presence of E-SRBC rosette forming cells was not always associated with the detection of LICC activity, as is the case with the thymus; (b) that, in the absence of detectable Eox-7S rosette forming cells (thymus and tonsils), NK and ADCC activities against tumor cells were always absent, but LICC was observed (tonsils), indicating that the presence of this Fc(7S) receptor bearing cells is strongly associated with the expression of NK and ADCC but not with LICC.
 ...
PMID:Comparison of the cytotoxic activities of different human lymphoid tissues. 9 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>