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Results for “Immunologic Surveillance”

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At least 19 recordsLinked to original sources
PubMed1979

Immunological surveillance against neoplasia: an immunological quandary.

Immunological endeavor in recent years calls for a reappraisal of the concept of immunosurveillance against neoplasia. This concept proposes an immunological policing system capable of aborting tumor growth by the recognition of "nonself" tumor associated antigens on neoplastic cells. The model is supported by evidence of tumor induction in the immunosuppressed host and the demonstration of an immune response to tumors in animals. The occurrence of tumor, regarded as a failure of immunosurveillance, is attributed to selection of neoplastic cells for immunological or other reasons or abnormal humoral or cellular antitumor immune responses. However protagonists of the postulate are faced with mounting evidence that fails to support the surveillance hypothesis. These observations include, inter alia, the monoclonality of certain tumors, the low incidence of spontaneous tumors in genetically immunodeficient mice and immunological privileged sites, and new ideas about the pathogenesis of lymphoproliferative neoplasms. However, contradictory arguments are not sufficiently substantiated to prosecute the case against surveillance conclusively. In citing highlights of the evolving quandary, both the pros and cons of immunological surveillance are presented here.

Animals↗
PubMed1978

Immunologic surveillance against chemically induced primary colon carcinoma in rats.

A 1,2-dimethylhydrazine dihydrochloride-induced rat gastrointestinal tract tumor model was used to study the phenomenon of immunologic surveillance. In two different sets of experiments, a properly timed administration of antithymocyte globulin resulted in earlier tumor appearance, increased numbers of tumors, and increased multiplicity of gastrointestinal tumors. Results obtained from histologic examination of the gastrointestinal tract at different times after the last dose of 1,2-dimethylhydrazine dihydrochloride suggested that a normally functioning immune system effectively suppressed the growth of some nascent tumors. However, the immunosuppression of the host with antithymocyte globulin allowed the development of foci of microtumors into grossly visible neoplasms. Our experiments supported the concept that immunologic surveillance against neoplasia depends on the thymus cell system, although other possible mechanisms were not excluded.

Animals↗
PubMed1979

[Results of a year's mycologic and immunologic surveillance of Candida in an intensive care ward].

Patients hospitalized in an intensive care unit must be considered to be exposed to a "high risk" in terms of candida infection. They often combine several of the factors favouring the development of "candida disease": generally deficient state, multiple antibiotics, iatrogenic or pathological immune depression. While certain patients who are admitted are already suffering from "candida infestation" (endogenous localization), the possibilities of exagenous infection are numerous. This study involved 63 patients spending at least one week in the department, from September 1977 to September 1978. Mycological (pharyngeal swab, urine culture, blood culture) and immunological (hemagglutination, immunoelectrophoresis, immunofluorescence) studies were carried out routinely on admission and then every week. Amongst the 63 patients studied, 12 were admitted with negative serology, which became positive during the first 10 days. 5 already had positive serology at the time of admission. From a mycological standpoint, the pharyngeal swab was frequently positive on admission (17 times out of 63). In 63 patients, the infection was acquired during the course of the hospital stay and, in this case, positive urine cultures were more regularly associated with a positive pharyngeal culture.

Candida↗
PubMed1978

[Immunological surveillance mechanism of a rat brain tumor model--study of time-lapse changes in the concomitant immunity of peripheral blood lymphocytes by microcytotoxicity assays (author's transl)].

A rat brain tumor model was prepared by semi-stereotactically implanting 1 x 10(6) RG--C6 tumor cells (chemically induced and maintained in vitro) in the right caudate nucleus of inbred WKA rat by a new method "Soft Agar Technique" which we developed. The tumor grew at a nearly fixed rate. We measured the maximum tumor area and the whole brain area of the rat brain which were sectioned coronary in series. We regarded the percentage of the tumor area to the whole area of the same section as tumor growth index. Microcytotoxicity assays of peripheral blood lymphocytes were performed at various stages of the tumor growth. RG--C6 cells were used as target cells, and they mixed with lymphocytes by Takasugi and Klein's method. Cytotoxicity index was higher in 22 cases (80.00 +/- 16.67; tumor growth index, 0--10) than in 28 cases of the control group (67. 25 +/- 19.68) and then gradually decreased with tumor growth (Fig. 2). At last cytotoxicity index went down to 41.55 +/- 24.94 in 11 cases (tumor growth index, over 31). These observations have a strong resemblance to other animal tumor models and suggest that the rat having brain tumor intra-axially have concomitant immunity especially in the first stage of tumor bearing.

Animals↗
PubMed1976

Random repression, immunological surveillance and hyperthermia.

A theoretical model of random repression of genetic information in a cancer cell is related to the efficiency of the immune system in removing cancer cells. It is suggested that at some elevated temperature, binding of a certain repressor molecule to the genome ceases and that the cell loses its random properties. We conclude with the idea that elevated temperature increases the efficiency of the immune system.

Adult↗
PubMed1976

The pathogenesis of Graves' disease.

Graves' disease may prove to be due to a genetic defect in immune surveillance or control, which then permits a randomly mutating thyroid-directed clone of T-lymphocytes to survive, interact with previously normal thyroid cell membrane antigen, and set up a localized cell-mediated immune response. The T-lymphocytes so interacting then cooperate with and direct groups of B-lymphocytes, which consequently produce TSI's: the stimulation of the thyroid parenchymal cells is a direct result of TSI stimulation. PHA stimulates Graves' lymphocytes to produce TSI's by first stimulating T-lymphocytes, which in turn interact with B-lymphocytes, which produce the TSI's. Normal thyroid antigen can stimulate sensitized lymphocytes to produce TSI's, which in turn can interact with normal thyroid cell membranes. This and other evidence suggests that there need not be any thyroidal antigenic change necessary to initiate hyperthyroidism. Stress may be related to the immunologic induction of the disease; it appears that remissions, other than those due to thyroid cell destruction, are immunologic. Exophthalmos may also prove to be an autoimmune disorder resulting from a closely related, but possibly not identical, defect in immunologic surveillance. Other related autoimmune diseases may result from similar related defects in immunologic surveillance, as well as from the random mutation of the appropriate forbidden clone.

Adolescent↗
PubMed1976

The incidence, pathology and transplantation of hepatomas in CBA mice.

Two hundred and seventy-five male CBA/Birmingham mice including 84 mice over 80 wk of age were autopsied at intervals over the whole range of their natural life span of about 2 1/2 yr. Body weight increased progressively up to 30 wk of age when a plateau value of 30-40 g was attained. Subsequent to 80 wk a slight, progressive decrease was observed. The thymus showed a profound increase in size from about 5 mg at birth to approximately 60 mg by the 3rd wk. Thereafter, the weight of the thymus decreased, rapidly at first, to reach 20-30 mg by 15 wk of age. The thymus weight then decreased more slowly to around 10 mg by the 80th wk. The spleen weight reached a plateau value of 50-60 mg by 4 wk and this was maintained until the 80th wk. In mice older than 80 wk varying degrees of splenomegaly were observed. Histologically, the areas of white pulp in these spleens were very prominent, suggestive of an on-going immune response. It was possible to associate this splenomegaly with the appearance of gross and microscopic evidence of hepatomas. No hepatomas were observed prior to 80 wk, but between 80 and 120 wk the incidence increased progressively; and all the mice whose age at autopsy exceeded 120 wk had hepatomas. Histologically the hepatomas showed marked nuclear plemorphism with occasional mitotic figures. Thrombi, areas of avascular necrosis and collections of inflammatory cells were observed. The tumour metastasised to the lung in 12% of cases. The doubling time of the hepatoma in situ was estimated as 1-6 wk (range 1-3-1-8 wk). These hepatomas were transplantable and grew with a doubling of 2-25 wk in syngeneic adult recipients. To test if the more rapid progressive growth of the tumour in situ in old CBA mice might have resulted from a breakdown in "immunological surveillance" the same tumour was transplanted simultaneously to a group of young and old recipients. The tumour grew more slowly (doubling time, 2-5 wk) in the old recipients. This result would not appear to support the hypothesis of a prolonged breakdown of immunological surveillance as the cause of the progressive increase in the incidence and growth of these tumours in situ in old mice.

Age Factors↗
PubMed1979

Myasthenia gravis and lymphoma. A clinical and immunological association.

Myasthenia gravis and lymphoma rarely coexist, but the occurrence of myasthenia shortly after the treatment of a patient with poorly differentiated nodular lymphoma suggested that an immunological disorder may have contributed to the development of both diseases; the fundamental defects in this association may be impaired immunological surveillance and impaired regulation of immune responses to autoantigens. The finding of T-cell immunodeificiency, including profound T-cell lymphopenia, impaired delayed hypersensitivity responses, and failure to a thymus-dependent antibody response to Salmonella adelaide flagellin, is consistent with this hypothesis.

Autoantibodies↗
PubMed1979

[Down syndrome: immunological study in adults (author's transl)].

The immunological profile was evaluated in 12 adults affected by Down's syndrome. Our findings showed: increase of serum IgG, IgA and Gammaglobulins, decrease of IgM, presence of auto-antibodies and increased antibodies response after antigenic stimulation (typhoid vaccination). Some tests, connected with T lymphocytes functions, were also abnormal: percentage of E-active rosettes, cutaneous sensibilization with DNCB and lymphocyte stimulation index with PHA. Our findings suggest a T lymphocyte deficit, with loss of immunological surveillance and therefore of the control over antibody mediated immunological reactions. The immunological alterations observed in our adult patients with Down's syndrome were more extensive and severe than those found in young subjects. The possible relevance of these findings is discussed as well as the incidence of Alzheimer's dementia in adult patients with Down's syndrome.

Adult↗
PubMed1977

Cytolytic thymus-derived lymphocytes specific for allogeneic stimulator cells crossreact with chemically modified syngeneic cells.

Mouse spleen cells cocultured with irradiated allogeneic stimulator cells develop cytolytic effector cells capable of lysing 51Cr-labeled syngeneic trinitrophenyl-derivatized tumor or spleen targets and to a lesser degree unconjugated tumor cells in addition to the allogeneic stimulator cells. Lysis of trinitrophenyl-syngeneic targets was inhibited competitively by cold trinitrophenyl-syngeneic tumor or spleen targets as well as by cells bearing the allogeneic stimulator H-2 haplotype demonstrating the immunological specificity of the interaction. Allogeneic H-2 specificities may, therefore, be considered variants of modified autologous H-2 specificities against which cytolytic thymus-derived clones potentially exist that are capable of exerting immunological surveillance.

Animals↗