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Biomedical subjects

J C Roder

Publications and source records attributed to J C Roder.

At least 127 records · Page 7Linked to original sources
PubMed1981

Induction of malignant lymphoreticular cell line which displays spontaneous killer-cell activity.

The origin and properties of a new malignant "spontaneous killer" cell line are described. The tumor, known as M9-78, was produced by treatment of tissue cultures consisting mostly of dividing DBA/2 mouse macrophages with the chemical carcinogen, 3-methylcholanthrene. Logarithmic phase cultures were treated for 6 days followed by further culture for 1 month in the absence of carcinogen. Subcutaneous injection of normal DBA/2 mice with 2.0 X 10(5) cells led to the formation of palpable tumors at the site of inoculation within 14 days; the tumors grew progressively and were highly metastatic. The malignant cells, though Fc-receptor-positive, did not possess many other properties normally associated with macrophages; morphologically, they bore a strong resemblance to bone-marrow-derived promonocytes. Because promonocytes have been shown previously to possess both antibody-dependent killer (K) cell as well as antibody-independent spontaneous killer-cell function, the M9-78 cells were tested for these biologic activities. The following results were obtained: (1) adherent, but not non-adherent, M9-78 tissue culture cells spontaneously killed a wide variety of (though not all) tumor-cell-line targets in long-term (18-24 h) 51Cr release, whereas no killing was seen in short (4 h) assays; (2) the cells were not capable of killing nucleated targets by antibody-dependent cell-mediated cytotoxicity; (3) a number of clones were obtained and tested for spontaneous killer-cell activity: some were highly active, whereas others were negative, with different patterns of specificity being evident; (4) the clones were unstable; (5) the pattern of target killing, when compared to normal spleen control NK cells, suggested the M9-78 cells were similar to activated macrophages or promonocytes in their target selectivity, although no definitive evidence was obtained which could implicate a promonocyte or monocyte origin for the cells.

Animals↗
PubMed1981

Selective natural killer resistance in a clone of YAC lymphoma cells.

YAC lymphoma cells were treated with the mutagen N-methyl-N'-nitro-N-nitrosoguanidine and then cloned and subcloned. Of 51 clones, 3 were selected for further study. Ten-fold more natural killer (NK) effector cells were required to lyse YAC clone 6 and subclone 6-28 cells compared with clone 19 cells or the YAC parent cell line. The maximum plateau level of cytolysis of the NK-resistant (NKR) variants (20%) never approached that of the NK-sensitive (NKS) variants or YAC parental cells (60%) even after prolonged incubation (20 hr). NKR variants appeared with equal frequency (0.10) on cloning YAC cells that had not been treated with mutagen but these variants were highly unstable with respect to NK sensitivity and were not studied further. Cytolysis of both NKR and NKS lines was mediated by nylon-nonadherent asialo-GM1+ effector cells, and effectors from poly(I) . poly(C)-boosted mice preferentially lysed the NKS lines. The NKR alteration did not appear to change the NK target structure (NK-TS): (i) unlabeled NKR cells competed equally with NKS cells in reciprocal unlabeled-target competition assays; (ii) the frequency of target--effector conjugates was identical with NKR or NKS lines; and (iii) normal rabbit serum, which contains antibodies thought to react with the NK-TS, reacted equally against both NKR and NKS targets. The NKR alteration was selective for NK cells and did not result in a resistance to lysis in general; NKR and NKS variants were equally susceptible to (i) cytolysis mediated by alloimmune or lectin-dependent effector T cells and (ii) antibody- and complement-mediated lysis. These results are compatible with the hypothesis that the NKR variants have an altered acceptor site on the target cell membrane that normally binds the "lytic moiety" delivered by the effector cell.

Animals↗
PubMed1981

EA rosettes using IgG monoclonal antibody-coated erythrocytes: degree of rosette formation correlates with the amount of antibody on the erythrocytes.

The EA (Fc receptor) rosetting assay, which utilizes sheep erythrocytes (SRBC) coated with anti-SRBC antibodies as indicator cells (EA) is a rapid and convenient method for the detection of Fc-receptor-positive cells. To prevent haemagglutination of the EA indicator cells, it has been necessary to dilute conventional SRBC antisera. Owing to this technical restriction, it has not been possible to determine accurately the contribution of antibody density on the EA indicator cells to the level of Fc-receptor-positive cells measured in the EA rosetting assay. However, the availability of high-titred non-haemagglutinating monoclonal anti-SRBC antibodies has provided a means of examining this problem. Four non-haemagglutinating monoclonal anti-SRBC IgG preparations-two of the IgG2a subclass, an IgG2b subclass-specific and an IgG1 subclass-specific antiserum-were used to coat SRBC at antisera dilutions ranging from 1/20 to 1/2000. The amount of antibody bound to the SRBC was determined by an indirect radioimmunoassay utilizing 125I-labelled protein A. The four monoclonal anti-SRBC antibodies were shown to have unique affinities for the erythrocytes, and each was specific for antigens present in differing amounts on the SRBC. The number of Fc-receptor-positive cells detected in a spleen cell suspension or in a homogeneous Fc-receptor-positive tumour cell population by the EA (Fc) rosetting assay was found to be directly proportional to the amount of monoclonal antibody (regardless of the IgG subclass) bound to the EA indicator cells.

Animals↗
PubMed1980

In vitro NK-activity and in vivo resistance to leukemia: studies of beige, beige//nude and wild-type hosts on C57BL background.

The bg mutation in C57BL mice causes a partial impairment of NK activity, and has therefore been proposed as a model to evaluate the in vivo function of NK cells. In the present report, we studied natural resistance against the ascitic lines of one chemically and two virally induced syngeneic leukemias in C57BL bg/bg mice and their phenotypically normal heterozygous +/bg littermates. S.c. threshold inocula of all three leukemia lines grew faster and caused death earlier in bg/bg than in +/bg mice, and two of the lines were rejected completely at a significantly higher frequency in +/bg control animals. The +/bg mice also eliminated [125I]-IdUrd-labelled leukemia cells at a faster rate than bg/bg mice, as measured by pulmonary, hepatic and splenic radioactivity retained 18-30 h after i.v. injection. Direct splenic killing of 51Cr-labelled leukemia cells was also studied in vitro, and was found to be severely depressed in bg/bg compared to +/bg. This natural killer activity was independent of adherent cells and showed a rapid, but transient, increase after inoculation of the tumor cell doses used in the transplantation tests. It was also possible to study the bg mutation in T-cell-free mice, by combining it with the nu mutation on a C57BL background. The NK activity of such beige-nude mice was found to be partially impaired compared to nude (non-beige) or wild-type animals, but higher than that of beige (non-nude) mice. Our results suggest that NK cells may be responsible for elimination of small numbers of tumor cells in the intact syngeneic host. The further use of beige and beige-nude mice in studies of transplanted and primary tumors is discussed.

Animals↗
PubMed1980

A new immunodeficiency disorder in humans involving NK cells.

Immunodeficiency disorders have provided much information on the development and interaction of the various B and T lymphoid components in the immune system of man. As the lymphoid system becomes increasingly divided into functional subsets of cells it will be important to find immunodeficiencies affecting newly discovered cell types. Natural killer (NK) cells are a recently described but ill-defined subpopulation of lymphocytes which is thought to play an important part in surveillance against tumour development. Mice homozygous for the beige gene were found to have a selective deficiency in NK function and were more susceptible to transplantation of syngeneic tumours as predicted. We report here that patients carrying the analogous, autosomal recessive Chediak-Higashi (CH) gene have a profound defect in their ability to spontaneously lyse various tumour cells in vitro by either antibody-dependent or independent mechanisms. Since other cell-mediated cytolytic functions were relatively normal, these results suggest that the beige or Chediak-Higashi gene in both man and mouse controls NK function.

Adult↗
PubMed1980

Target-effector cell interaction in the natural killer cell system. V. Energy requirements, membrane integrity, and the possible involvement of lysosomal enzymes.

Various inhibitors were used to study further the mechanism of natural killing and to compare it to lympholysis by cytotoxic T lymphocytes (CTL). The respiratory inhibitors DNP and NaN3 or low temperatures (0 degrees) blocked the cell contact phase of target-effector interaction in the CTL system but not the NK system. The lytic stage was also inhibited by the glycolytic inhibitors, iodoacetate and NaF, in the NK system as previously shown in the CTL system. Dimethylsulphoxide, a dipolar solvent, and cytochalasin B, a microtubule disruptor, inhibited NK target binding. Pre-treatment of Nk cells with glutaraldehyde, a protein cross-linking agent, completely prevented lysis, but not the formation of target-effector conjugates. The lytic phase of NK lysis was inhibited by chloroquine which also inhibited lysosomal enzyme function. Lysosome defective, beige mutant mice were also totally deficient in NK lytic function and this defect could not be restored with cGMP. T-cell and macrophage mediated cytolysis was previously shown to be relatively normal in beige mice. These results suggest that (i) the mechanism of NK cytolysis is a complex, multistep process, and (ii) this process is fundamentally different from that occurring in CTL. A 'stimulus-secretion' model of NK cytolysis is presented in which it is postulated that lysosomal enzymes may be the lytic molecules.

Animals↗
PubMed1980

Target-effector interaction in the natural killer (NK) cell system. VI. The influence of age and genotype on NK binding characteristics.

Four independent assays were used to compare target-cell binding by NK cells in different populations. First, detergent solubilized and reduced proteins from the surface of Moloney lymphoma cells (YAC) were electrophoresed in SDS-polyacrylamide gels. The glycoproteins recognized by NK cells (NK-TS) were eluted from the gels and used in semi-quantitative absorption studies or were used to inhibit the formation of target-effector conjugates as an estimate of relative avidity. These findings were supported by a comparative analysis of cold target competition curves and saturation studies in which 51Cr-labelled target cells were carefully titrated. The results suggest that NK cells 'mature' during ontogeny to higher avidity binding whereas the decline in NK function during senescence can solely be attributed to a decrease in population size. A comparison of high (CBA) and low (A/Sn) NK reactive strains revealed that in low responder (i) absolute NK frequency was decreased, (ii) relative NK-TS absorption per NK cells was low, and (iii) relative avidity of NK cells was identical to that in the high responder strain. These results suggest that the putative NK receptor to YAC may be of restricted heterogeneity.

Absorption↗
PubMed1979

Target-effector interaction in the human and murine natural killer system: specificity and xenogeneic reactivity of the solubilized natural killer-target structure complex and its loss in a somatic cell hybrid.

Preincubation of natural killer (NK) cells with electrophoresis purified proteins from a variety of NK-sensitive murine and human tumor cells specifically prevented subsequent binding to the intact, homologous target cell. The NK-target structures (NK-TS) consisted of some or all of four characteristic molecular species, tentatively assigned molecular weights of 140K, 160K, 190K, and 240K (+/-10K) based on electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels. When these NK-TS molecules were compared in cross-inhibition assays, the large 240K molecule most often carried the unique NK specificity, whereas the smaller 140K molecules cross-reacted between YAC, 136-6 and X-63 in the mouse and between Molt-4 and K562 in the human. Mouse NK cells recognised a different spectrum of NK-TS molecules than human NK cells. The control of NK-TS expression was partially revealed in a cloned, somatic cell hybrid bwtween an NK sensitive (YAC-IR) and insensitive (A9HT) cell line. The hybrid did not express NK-TS and did not bind to NK cells which is in accordance with negative NK cytolytic results previously reported. Although unique specificities are carried by some of the multiple NK-TS protein molecules, cross-reactions were widespread. These observations taken together suggest that the NK cell is polyspecific and has some heterogeneity in the recognition structure although much less than would be expected of an antibody-combining site.

Animals↗
PubMed1979

A functional comparison of tumor cell killing by activated macrophages and natural killer cells.

This report compares the sensitivity of 17 tumor cell lines to cytolysis mediated by natural killer (NK) cells or by activated, bone marrow-derived macrophages (AM) from 15 inbred mouse strains. Some tumor cell lines, notably P815, were highly sensitive to AM-mediated lysis but almost completely insensitive to NK cells, whereas other cell lines were lysed by NK cells but not AM. In a genotype survey, some low-responder strains in the NK system, such as A/Sn, were high responders in the AM system, and conversely, one intermediate to high-responder strain (C3H/HeJ) in the NK system was a low responder in AM-mediated cytolysis. In addition, macrophage cytotoxicity factor was necessary to activate macrophages, but this lymphokine did not augment NK activity. Furthermore, the NK population did not contain pre-activated macrophages since pre-activated cells were removed on glass bead columns or by iron carbonyl and a magnet; treatments which have been previously shown not to affect NK cells. These results suggest that NK cells are distinct from AM in physical characteristics, target selectivity, genotype distribution and the mechanism of cytolysis.

Animals↗
PubMed1979

Target-effector interaction in the natural killer cell system: isolation of target structures.

A sensitive target binding assay has recently been shown to detect natural killer (NK) cells in the mouse. Preincubation of NK cells with detergent-solubilized cell-surface proteins of YAC lymphoma cells prevented subsequent binding to intact YAC targets. The NK target structures (NK-TS) consisted of three molecular species tentatively assigned molecular weights of 130,000, 160,000, and 240,000 based on electrophoretic mobility in sodium dodecyl sulfate/polyacrylamide gels. Moloney cell surface antigen (MCSA), gp71, p30, H-2, and NK-TS were localized in distinct fractions of gels. The NK-TS bound to concanavalin A-Sepharose columns and could be eluted with the specific sugar, suggesting that the target structures may be glycosylated. NK-TS molecules could not be detected in gels of NK-insensitive target cells such as P815, A9HT, YWA, or EL-4. The quantity obtained from the gels varied directly with the NK sensitivity of YAC which is more sensitive when grown in vitro than when grown in vivo. The NK-TS molecules specifically inhibited the binding of NK cells but not alloimmune T cells to their appropriate targets. Additional NK-sensitive tumor cells also expressed some or all of the target molecules exhibited by YAC. Some of these structures shared specificities in the case of MPC-11 or were unique in the case of Molt-4 and K562, as shown by cross-inhibition studies. These results suggest that NK-sensitive cell lines express distinct target structures with possible relevance to natural tumor resistance.

Animals↗