Specificities in human cell-mediated cytotoxicity

Effect of BCG Immunotherapy on Cell-Mediated Cytotoxicity in Bladder Cancer Patients following Surgical Treatment

Peripheral blood lymphocytes from bladder cancer patients display in vitro cytotoxicity against established bladder tumor target cells. Following surgery and after separation of lymphocytes in non-T and T with high affinity and low affinity for sheep erythrocytes fractions, the cytotoxic activity was significantly decreased in all subsets. After BCG therapy the cytotoxic capacity was restored and the effect was equally distributed in the different subpopulations. The monocyte-enriched fraction did not show any change in the cytotoxic activity after treatment.

Effects of isolation on interferon production and hematological and immunological parameters

A 27-year-old woman was maintained in an isolated state for 131 days in Carlsbad Caverns, New Mexico. Her diet was vitamin D-depleted. Determinations on the effects of such isolation on levels and activities of peripheral blood cells that are important for hematological homeostasis and immunological function were carried out. Throughout the duration of the study, the percentage of lymphoid cells that expressed CD3, CD4, CD8, CD19, Leu 8, and other markers remained relatively constant although the absolute numbers of these cells varied. Although the percentage of natural killer (NK) cells did not vary, the activity of these cells did change. NK cell activity became elevated as the isolation study progressed. Production of interferon-gamma (IFN-gamma) in response to mitogen stimulation was higher than expected throughout the isolation periods, but returned to the normal range after termination of the isolation. Red and white cell counts dropped significantly upon entering isolation, but soon returned to normal.

Natural killer cells: artifact to reality: an odyssey in biology

The biology of the natural killer cell system is being investigated by many different laboratories using multiple approaches. The rationale for these investigations is the experimental evidence that NK cells play some role in inhibiting tumor growth and metastasis, convey some protective immunity and may be operative in control of differentiation from fetal life to adulthood. Thus, a survey of the literature reveals a multiplicity of studies examining many of these potential roles for NK cells. This review will attempt to summarize some of the findings critical to an understanding of the role NK cells play in immunophysiology and in immune reactions to various diseases. Even after ten years of study, the whole system of 'natural' reactivity remains difficult to define. The evidence available would indicate that the NK system while incompletely understood, may be manipulated in favor of the host when threatened by infectious or neoplastic disorders.

The biology of the human natural killer cell

Natural killer (NK) cells in the human are a population of large granular lymphocytes (LGL) with at least one unique surface antigen not expressed on cells of other lineages. NK-target-cell interaction appears to involve carbohydrate recognition and, following binding, the NK cells are induced to generate O2-, transmethylate membrane phospholipids, and activate phospholipase A2. Some or all of these activities trigger a cascade of events which ultimately leads to the secretion of a substance toxic to the target cell. A variety of genes controls various steps in this cytolytic pathway. There is a good deal of evidence in the mouse, and some in the human, that NK cells play a role in host surveillance against tumor development, resistance to viral infections, and, possibly, hematopoietic regulation.

Effector cells in natural cytotoxicity against human bladder cancer cell lines

Human peripheral blood mononuclear cells obtained by ficoll-hypaque sedimentation were depleted of Fc-receptor-bearing (FcR+) cells. Cytotoxicity (direct killing of target cells by effector cells), tested in a 40 h assay, was significantly decreased against a variety of target cells. Tests in which no FcR+ cells could be detected were also positive for "natural killing" (NK) against a spectrum of target cells from normal donors. NK in this system was mediated by more than one subpopulation of lymphocytes. Monocytes probably did not play a significant role. Decreasing the FcR+ cells in peripheral blood mononuclear cells in patients with bladder cancer and in controls did not reveal specific antitumor activity.