Immunostimulation of blood monocyte function by RU 41.740 (Biostim) in patients with chronic bronchitis

Phagocytes and Their Pharmacological Modulation in Chronic Bronchitis

Altered values of many functional properties of both peripheral phagocytes (neutrophils and monocytes) and alveolar macrophages were demonstrated in patients with chronic bronchitis. Out of this population 16 patients with defective phagocytosis index were included in an open randomized trial to investigate the effect of RU41740, a glycoprotein extract of K1. pneumoniae, on this phagocytic function and its efficacy in reducing the number of exacerbations.

A relationship between the restoration of the immunological parameter and the clinical improvement was demonstrated. This effect suggests that phagocytosis can play a role in protecting patients with chronic bronchitis from infectious exacerbations.

Immunomodulatory effect of various anti-parasitics: a review

This paper reviews the immunomodulatory effects (immunosuppression or immunoactivation) of various anthelmintics including levamisole, fenvalerate, dieldrin, carbofuran, aminocarb, thiabendazole, fenbendazole, oxfendazole and ivermectin. The induced modulation of immune function may occur via direct and/or indirect mechanisms. The immunomodulatory effects of these anti-parasitics have been studied in a variety of bacterial (e.g. brucellosis, salmonellosis, paratuberculosis, mastitis), viral (e.g. infectious bovine rhinotracheitis, Herpes, foot and mouth disease), parasitic (e.g. onchocerciasis, coccidiosis, ascariasis, schistosomiasis) and neoplastic diseases. Some antiparasitics have also been used to boost immunity in a number of human diseases including leprosy, Hodgkin's disease, rheumatoid arthritis, and in adjuvanted therapy of colorectal cancer. The ability to stimulate the immune response of animals offers a new means of disease intervention. Future research on immunomodulatory effects of anti-parasitics, for humans and domestic farm animals, will provide additional methods of treating immunosuppressed subjects. The immunopotentiating or immunosuppressing activity of anti-parasitics will dictate whether co-administration of vaccines and anthelmintics or administration of vaccines during the window of immunoactivation is justified or not.

Impaired systemic cell-mediated immunity and increased susceptibility to acute respiratory tract infections in patients with COPD

Although it has been reported that chronic obstructive pulmonary disease (COPD) is frequently associated with systemic immune disturbances, negative impact of these disturbances on the increased prevalence of acute respiratory tract infections (aRTIs) has remained unclear. We evaluated circulating levels of interferon-gamma (IFN-gamma), soluble interleukin-2 receptor (sIL-2R), neopterin, and soluble intercellular adhesion molecule-1 (sICAM-1) in 35 clinically stable patients with COPD and in 22 age-matched healthy controls, since these molecules are considered to reflect the in vivo status of systemic cell-mediated immunity (CMI). We found that circulating levels of sIL-2R (1.52+/-1.25 vs. 0.97+/-0.48 ng/ml; P<0.05), neopterin (7.23+/-4.24 vs. 4.95+/-1.52 nmol/l; P<0.05), and sICAM-1 (665+/-302 vs. 328+/-164 ng/ml; P<0.0001), but not IFN-gamma (7.55+/-4.72 vs. 6.65+/-1.13 pg/ml; P=NS) were significantly higher in patients with COPD than in the controls. Importantly, follow-up study for 12 months demonstrated that patients in subgroup with relatively higher circulating levels of sIL-2R (2.20+/-1.44 ng/ml, n=18) had significantly higher risk of developing aRTIs (P=0.0204) than those in subgroup with relatively lower circulating levels of sIL-2R (0.80+/-0.23 ng/ml, n=17). These results may suggest that impaired systemic CMI observed in COPD patients is associated with the increased susceptibility to aRTIs in these patients.

Defective natural killer and phagocytic activities in chronic obstructive pulmonary disease are restored by glycophosphopeptical (inmunoferón)

We have investigated both modifications in natural (innate) immunity caused by chronic obstructive pulmonary disease (COPD) and the effects of a glycophosphopeptical immunomodulator (Inmunoferón) treatment on COPD-associated immunoalterations. In a double-blinded clinical trial, 60 patients with COPD received glycophosphopeptical or placebo during 90 consecutive days at oral doses of 3 g/d. Fifty-six sex- and age-matched healthy control subjects were included as a reference group for immunologic parameters. Peripheral blood natural killer (PBNK) cell cytotoxic activity and phagocytic activity of peripheral monocytes/macrophages (Mo/Ma) and polymorphonuclear (PMN) cells were assessed at baseline and then again at the end of treatments. We found both PBNK activity and phagocytic activity to be significantly decreased in patients with COPD compared with levels in healthy volunteers. The treatment with glycophosphopeptical provoked significant stimulatory effects on PBNK cytotoxic activity. This stimulation was not mediated by an increase in CD3(-)CD56(+) NK cells. Further, glycophosphopeptical significantly increased the percentage of monocytes and PMNs that phagocytize Escherichia coli in vitro, as well as increased phagocytic indices. We conclude that peripheral blood cells of patients with COPD show clear defects in natural immunity that are partially rescued by glycophosphopeptical.

Protective effects of RU 41740, a bacterial immunomodulator, against experimental infections: induction of cytokine and immunoglobulin release in mice after oral administration

RU 41740 (Biostim) is an immunomodulator extracted from Klebsiella pneumoniae (strain O1:K2). In humans, it is able to reduce the number and duration of infectious exacerbations of chronic bronchitis. Using a mouse model of experimental infection, we found that oral RU 41740 administration strongly protected against gram-negative infections by preventing lethal septicemia, and, to a lesser extent, protected against the gram-positive intracellular pathogen L. monocytogenes. Oral administration of RU 41740 leads to the mobilization of newly dividing T and B cells in the thoracic duct lymph, reflecting the ability of the drug to induce an immune response in gut-associated lymphoid tissue. In cells isolated from mesenteric lymph nodes and spleen, RU 41740 leads to preferential release of the proinflammatory cytokines interleukin (IL)-12 and/or interferon (IFN)-gamma, as well as IL-10, a cytokine involved in inhibiting the synthesis of these latter cytokines. RU 41740 also increases the serum total immunoglobulin (Ig)M concentration and elicits IgM and IgG antibodies against the drug. Infection of mice with Klebsiella pneumoniae has similar functional consequences. Pretreatment of infected mice with RU 41740 leads to a fall in the high levels of proinflammatory cytokines (which could be detrimental), and to an increase in IgG antibodies (which are protective).

The immunomodulating glycoprotein extract from Klebsiella pneumoniae RU 41740 exerts a suppressive effect on human monocyte death by apoptosis

Programmed cell death or apoptosis is a physiological cell suicide process that can be suppressed by survival factors. Monocytes undergo rapid apoptosis in culture, unless signalled by cytokines or the bacterial lipopolysaccharide LPS. We have investigated the effect on monocyte apoptosis of the immunostimulating agent RU 41740 (Biostim), a glycoprotein extract from the Klebsiella pneumoniae K2O1 strain that is used for the prevention of recurrent infections. RU 41740, as LPS, strongly enhanced monocyte survival in vitro, an effect related to apoptosis suppression. RU 41740 at concentration ranging from 1 ng/ml to 10 microg/ml prevented apoptosis induced both by survival factor deprival and by gamma-irradiation. Our observation suggests that enhancement of monocyte survival may represent a component of the reported immunostimulating effect of this compound.

Effect of an immunomodulating agent, RU 414740, on polymorphonuclear responsiveness after burn injury

An impairment of polymorphonuclear leukocyte (PMN) functions has been described following burn trauma. It was thus of interest to investigate the effect of RU 41740, an agent known to stimulate these cells, on rat PMN functions after burn injury. In the present study the responsiveness to classical stimuli of PMN from untreated burned rats was approximately 40% lower than healthy control values. In vitro treatment with RU 41740 increased oxidative metabolism of PMNs from burned and healthy rats. The effect was dose-related but was most striking in the case of PMNs from healthy rats. Significant differences were obtained with concentrations higher than 1 micrograms/ml for healthy rats but only 10 micrograms/ml for burned rats. In vivo treatment with RU 41740 also led to an enhancement of PMN oxidative metabolism on both burned and healthy rats. The maximal effective dose was 10 mg/kg/day in both cases. In contrast, 25 and 50 mg/kg/day doses inhibited PMN oxidative metabolism.

Increased expression of C3b and C3bi receptors on human neutrophils and monocytes induced by a glycoprotein extract from Klebsiella pneumoniae (RU41740)

RU41740 is a glycoprotein extract from Klebsiella pneumoniae with immunomodulating properties under different experimental conditions. In particular the compound is able to stimulate several functions of human phagocytes in vitro and ex vivo. Using monoclonal antibodies and flow cytometry, in this work we assessed the effect of RU41740 on surface expression of receptors for C3b (CR1) and C3bi (CR3) in human phagocytic cells in vitro. The incubation of whole blood with varying RU41740 concentrations led to a dose-dependent increase in surface expression of CR1 and CR3 on both neutrophils and monocytes when compared with control samples incubated in buffer alone. The maximal drug-induced enhancement of complement receptors was: 291% +/- 13.4% for CR1 and 265% +/- 8.5% for CR3 in neutrophils; 117% +/- 4.5% for CR1 and 98% +/- 4.1% for CR3 in monocytes. These peak effects were observed using RU41740 at a final concentration of 10 micrograms/ml and were similar to those induced by optimal concentrations of the activating compound N-formyl-methionyl-leucyl-phenylalanine (10(-7)M). Polymyxin B did not modify the RU41740-induced enhancement of CR1 and CR3 expression on phagocytes, suggesting no role for endotoxin in this activity. These results define, at least in part, the mechanism of action of RU41740 on human phagocytes in vitro and could be relevant to in vivo events during RU41740 treatment.

The effect of Biostim (RU-41740) on the expression of cytokine mRNAs in murine peritoneal macrophages in vitro

The immunomodulatory agent Biostim (RU-41740) was investigated for its ability to induce the expression of cytokine mRNAs in murine peritoneal macrophages in vitro. Northern blot analysis showed that in quiescent macrophage populations, both IL-1 alpha and IL-1 beta mRNA levels were dramatically increased in response to 1 microgram/ml Biostim. Dot-blot analysis showed that in quiescent macrophage populations the expression of mRNAs for IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha could be elevated by concentrations of Biostim as low as 1-10 pg/ml, detectable after 3 h exposure. In parallel experiments LPS was effective only at the higher concentration of 10 ng/ml. Time-course analysis showed that the expression of these cytokine mRNAs was transient, peaking after 1-3 h; only transcripts of IL-1 beta were detectable after 23 h exposure. No effects were seen on the expression of actin, a high-turnover housekeeping gene. We propose that this type of analysis represents a sensitive, specific and reproducible method for assessing the ability of drugs and chemicals to modulate the expression of cytokines that play a pivotal role in the induction of the immune response.

Immunological activities of RU-41740, a glycoprotein extract from Klebsiella pneumoniae. III. Role of LPS-like and LPS-non-related molecules

RU-41740, a glycoprotein complex extracted from Klebsiella pneumoniae, is an immunomodulating agent which acts on B cells and macrophages. It has been shown that RU-41740 is composed mainly of two macromolecular fractions, F1, having an LPS-related structure, and P1, with a proteoglycan structure. In the present paper, the effects of these molecules on B cells and on IL-1 and tumour necrosis factor (TNF), production by macrophages were compared. Data reveal that both fractions were mitogenic for murine B cells and induced IL-1 and TNF production by macrophages. The LPS-like fraction (F1) was sensitive to polymyxin B and was unable to activate macrophages and spleen cells from LPS non-responder mice. The P1 fraction was mitogenic for B cells and induced the production of IL-1 and TNF activities by macrophages from LPS non-responder C3H/HeJ mice. The cytotoxic activity was due to TNF alpha, since treatment with anti-TNF alpha antiserum abrogated the lytic activity of supernatants from stimulated macrophages. The differences observed between P1 and F1 fractions in terms of sensitivity to polymyxin B and activity towards C3H/HeJ spleen cells and macrophages suggest that the two structurally distinct molecules isolated from RU-41740 could act at different sites on immunocompetent cells.

In vitro modulation of human monocytes functions by RU 41740 (Biostim)

The in vitro effects of RU 41740, a mixture of two glycoproteins extracted from K. pneumoniae and possessing immunomodulatory activity, on human monocyte's cytotoxic activity, migratory capacity and monokine production were investigated. Exposure to RU 41740 in nanogram concentrations was associated with rapid increases in IL-1 and TNF production and marked augmentation in the monocytes' killing of TNF-sensitive targets, whereas killing of TNF-insensitive targets required longer exposures to microgram concentrations of this drug. Using otherwise effective treatment conditions, RU 41740 did not directly affect monocyte's spontaneous and FMLP-induced migration. The possible role of mononuclear cells stimulation and increased production of effector and regulatory monokines in the immunomodulatory activity of this product is addressed.

In vitro and ex vivo effect of RU41740 on human polymorphonuclear leukocyte function

We investigated the effect of RU41740, a glycoprotein extracted from Klebsiella pneumoniae and possessing immunomodulating properties, on human neutrophil functions in vitro and ex vivo. Our in vitro results showed that RU41740 increased complement- and Fc receptor-dependent phagocytosis. Moreover, the drug enhanced the oxidative metabolism (assessed by chemiluminescence) both in resting and stimulated cells; in the latter case the RU41740-induced enhancement was observed when neutrophils were stimulated with opsonized particles of N-formyl-methionyl-leucyl-phenylalanine (FMLP) but not when phorbol myristate acetate was used. Using otherwise effective experimental conditions, RU41740 did not affect spontaneous or FMLP-induced neutrophil migration. For the ex vivo experience we tested neutrophils of ten elderly subjects with a previously demonstrated phagocytic defect. These subjects were treated orally with RU41740 at a daily dose of 2 mg for 1 week during the first month, and of 1 mg for 1 week in the second month. In this population, RU41740 was able to restore the impaired phagocytic activity and to induce a significant increase of spontaneous chemiluminescence (CL); stimulated CL was also positively influenced. These effects on neutrophils provide new explanatory bases for the immunostimulatory activity of RU41740.