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Biomedical subjects

K E Hopper

Publications and source records attributed to K E Hopper.

5 recordsLinked to original sources
PubMed1979

Mechanism of resistance of mice to syngeneic methylcholanthrene induced fibrosarcomas.

Mice become resistant to challenge with certain fibrosarcomas when bearing a tumor graft (concomitant immunity) or after injection of a low, non-tumorigenic dose of cells (sinecomitant immunity). Resistance to footpad challenge was depressed or abolished by treatment with carrageenan, niridazole or reserpine, or by sublethal irradiation, all of which also depressed delayed-type hypersensitivity (DTH) reactions. Immune lymphocytes initiating tumor-suppressive reactions in the feet of non-immune mice were Thy-1+, Ly-1+, Ly-2- and Ly-3-. Injection of tumor cells into the peritoneal cavities of immune mice specifically elicited an influx of macrophages. There was evidence of macrophage stimulation in tumor-immune mice. In vitro, anti-tumor effector cells lacking individual tumor specificity could be detected among the resident peritoneal cells of tumor-immune mice and among peritoneal exudate cells of non-immune mice. The expression of acquired resistance to some tumors may involve reactions akin to DTH in which a specific reaction triggers an accumulation of nonspecific effectors.

Animals↗
PubMed1979

Macrophage heterogeneity.

Macrophages are a mobile, functionally diverse group of cells which may be recruited and stimulated to a high degree of metabolic activity. Heterogeneity may be detected from one site to another and result from local influences, e.g. lung v. peritoneal cells, or occur within a population and arise dur to different stages of differentiation, maturation or activation or possibly from distinct cell lines. Recruitment and turnover are important determinants of the diversity of cells at any one site. In addition, anti-tumour, anti-microbial and secretory capacities of macrophages are greatly influenced by the degree and nature of stimulation possibly affecting only a subpopulation of the cells. Accessory cell activity is also a function of a minor population of macrophages which have distinct surface antigens. The sources of the heterogeneity and the interrelationship between the macrophages subpopulations remain to be determined.

Animals↗
PubMed1978

Failure of immunogenic tumors to elicit cytolytic T cells in syngeneic hosts.

Immunogenic, methylcholanthrene-induced sarcomas failed to elicit the production of rapidly cytolytic T lymphocytes in syngeneic mice, although they did elicit the production of more slowly cytotoxic cells. They were, however, susceptible to attack by cytolytic T cells from allo-immune mice and, if infected with ectromelia virus, to attack by similar cells from virus-immune, H-2 compatible mice. It is suggested that the failure to elicit cytolytic T cell production may be due to the lack of an appropriate association between tumour-specific antigens and elements of the major histocompatibility complex.

Animals↗