Induction of long-term survival of rat skin allografts by a novel, highly efficient anti-CD4 monoclonal antibody.

The new monoclonal antirat CD4 antibody RIB 5/2, which detects another epitope than those covered by W3/25 and MRC OX35, was tested for its immunosuppressive potency following skin allografting by using strain combinations with different genetic barriers in the MHC and genetic low- or high-responder background. High-dose and long-term therapy of the grafted rats led to a significant delay of the acute rejection (P < 0.01) in the strain combination Wistar Furth-to-BDX as well as in LEW1W-to-LEW1A. No significant prolongation of the mean allograft survival time was obtained for the high-responder rats (LEW1A-to-LEW1W). Cytofluorometric analysis revealed that RIB 5/2 exerts the immunosuppressive activity predominantly by modulation of the CD4 glycoprotein. Furthermore, the dependence of the humoral immune response against the mouse-globulins upon the administered protein quantity could be demonstrated.

Human monocyte activation induced by an anti-CD14 monoclonal antibody.

An anti-CD14 mAb RoMo-1 rapidly induces in human monocytes a transient oxidative burst activity as detected by chemiluminescence assay. Pretreatment of these cells with the mAb markedly suppresses the monocyte chemiluminescence response to opsonized zymosan. In addition, the antibody induces a significant increase of IL-1 production and secretion by mononuclear cells, comparable to a similar effect of rIFN-gamma or LPS. Electron microscopy demonstrates internalization of the CD14 molecules after interaction with the mAb in a characteristic receptor-like manner.

Pancreatic adenocarcinoma cell lines show variable susceptibility to TRAIL-mediated cell death.

BACKGROUND AND AIMS: Programmed cell death via the Fas receptor/Fas Ligand and DR4, DR5/TRAIL plays a major role in tumor escape and elimination mechanisms. It also promises to be an effective therapy alternative for aggressive tumors, as has been recently shown for colon, breast, and lung cancer cells. We attempted to clarify the role of these molecules in aggressivity of pancreatic carcinomas and to identify possible pathways as targets for therapy. METHODS: Five pancreatic cell lines were investigated for the expression of FasL/Fas, DcR3, DR4, DR5/TRAIL, DcR1, DcR2, and other death pathways related molecules such as Bax, bcl-xL, bcl-2, FADD, and caspase-3 by flow cytometry, immunoblotting, and RT/PCR, both semiquantitative and real time (TaqMan). The susceptibility of these cell lines to apoptosis mediated by recombinant TRAIL was investigated. The effect of therapeutic agents (gemcitabine) on their susceptibility to TRAIL induced apoptosis was studied as well. RESULTS: Pancreatic adenocarcinomas expressed high levels of apoptosis-inducing receptors and ligands. They showed differential susceptibility to cell death induced by TRAIL, despite expressing intact receptors and signaling machineries. Treatment with commonly used therapeutic agents did not augment their susceptibility to apoptosis. This could be explained by the fact that they expressed differentially high levels of decoy receptors, as well as molecules known as inhibitors of apoptosis. CONCLUSIONS: The data suggest that pancreatic carcinoma cells have developed different mechanisms to evade the immune system. One is the expression of nonfunctional receptors, decoy receptors, and molecules that block cell death, such as bcl2 and bcl-xL. The second is the expression of apoptosis-inducing ligands, such as TRAIL, that could induce cell death of immune cells. The success in treating malignant tumors by recombinant TRAIL might apply to some but not all pancreatic tumors because of their differential resistance to TRAIL-induced cell death.

Does diet or alcohol explain the French paradox?

The low rate of coronary heart disease (CHD) in France compared with other developed countries with comparable dietary intake has been called the French paradox. We explored this paradox by looking at alcohol, diet, and mortality data from 21 developed, relatively affluent countries in the years 1965, 1970, 1980, and 1988. We assessed wine, beer, and spirits intake separately. France had the highest wine intake and the highest total alcohol intake, and the second lowest CHD mortality rate. In univariate analyses, ethanol in wine was slightly more inversely correlated with CHD than total wine volume. In multivariate analyses, animal fat tended to be positively correlated, and fruit consumption inversely correlated, with CHD. Beer and spirits were only weakly inversely correlated with CHD. The strongest and most consistent correlation was the inverse association of wine ethanol with CHD. However, wine ethanol was unrelated to total mortality. We conclude that ethanol, particularly wine ethanol, is inversely related to CHD but not to longevity in populations. Although light to moderate alcohol consumption may improve longevity, alcohol abuse--which sharply reduces longevity--is correlated with average alcohol consumption in populations. Thus, while the risk/benefit ratio varies for individuals, the use of alcohol for cardioprotective purposes should not be encouraged as a public health measure.

Potential mechanisms of the sleep therapies for depression.

Sleep deprivation for one night has been investigated as a treatment for depression since the first publications describing its antidepressant properties almost 30 years ago [Pflug and Tolle, 1971: Int Pharmacopsychiatry 6:187-196]. It remains a field of active research. It is the only intervention consistently demonstrated to produce next-day antidepressant results. This makes sleep deprivation an exciting and unique tool to study the pathophysiology of depressive disorders and to formulate targets for novel antidepressant agents. Importantly, it is also an effective, but underused, clinical treatment for unipolar and bipolar depression.

Effect of recombinant human tumor necrosis factor on tumor and spleen in mice.

The ability of recombinant human tumor necrosis factor (rH-TNF-alpha) to induce regression of sarcoma 180 in vivo was evaluated. The tumor was cured by TNF in the course of 4 weeks. TNF inhibited proliferation of sarcoma 180 cells in vitro, which suggests a direct effect of TNF on tumor cells in vivo. In parallel to the TNF effect on tumor growth, some cell parameters in spleen were investigated. Activation of splenic macrophages was enhanced in vitro. This result suggests that macrophages may participate in the host defense against the tumor. In the first phase of therapy, TNF did not affect the proliferation of splenocytes but increased the transition of G0 into G1 cells. Furthermore, TNF normalized the tumor-induced increase of null cells in tumor-bearing mice. All parameters investigated in spleen reached normal values at the time of tumor regression. Our results suggest that various mechanisms may be involved in TNF-induced regression of sarcoma 180.

Immunological reactivity of tumor associated glycoproteins prepared by affinity chromatography.

Crude 3M KCl extracts prepared from tumor tissue and ascitic tumor cells of methylnitrosourea-induced fibrosarcoma of CBA mice or of a human stomach adenocarcinoma were gelfiltrated on Ultrogel AcA 34. Single fractions of these preparations were incubated with spleen cells of tumor bearing mice or blood peripheral lymphocytes. The response was detected by MEM-technique. Antigenic activities were found in molecular weight ranges from 200 to 300 kD (P1) and from 40 to 70 kD (P2). Single glycoproteins of the P1- and P2-fractions could be separated by affinity chromatography on immobilized D-galactose specific mistletoe lectin I, as detected by electrophoresis on microgradient gels (1.2-40%) or on SDS polyacrylamide slab gels. Especially the isolated glycoproteins of the P1-fractions are responsible for the observed antigenic reactivity, assayed in vitro by the MEM-technique and in vivo by foot pad swelling test.

Use of human preconditioned phagocytes for extracorporeal immune support: introduction of a concept.

Neutrophils are critical effector cells in humoral and innate immunity and play a vital role in phagocytosis and bacterial killing. If they and/or their specific functions are lacking, then immunoparalysis may occur, and severe diseases like systemic inflammatory response syndrome (SIRS) or sepsis can take a fatal course. In this paper, we discuss the possibility of using preconditioned cells in an extracorporeal biohybrid immune support system. A human promyelocytic cell line was stimulated for different times with all-trans retinoic acid. The resulting cells displayed major signs and functions of mature neutrophilic granulocytes including oxygen radical production, phagocytosis of living and dead Escherichia coli, Staphylococcus aureus, Candida albicans, intracellular killing, and interleukin production. The cells can be expanded to yield a sufficient cell mass, and subsequent prestimulation results in an expression of specific neutrophil functions. Extracorporeal bioreactor experiments seem to be feasible to test the benefit in immunoparalysis-associated diseases like SIRS or sepsis.