Dynamics of the humoral immunity indices in patients with subacute brucellosis being treated with levamisole

The dynamics of the main characteristics of humoral immunity in patients with subacute brucellosis, receiving levamisole and placebo, has been studied. Levamisole produced an immunomodulating effect manifested by an increase in the number of B-lymphocytes and a drop in the level of circulating immune complexes. Levamisole did not essentially influence the content of serum immunoglobulins and specific antibodies.     

The etiopathogenetic treatment of experimental tuberculosis using preparations with immunomodulating action

The effectiveness of the complex chemotherapy of experimental tuberculosis in combination with the remedies of pathogenetic therapy has been studied. The immunomodulating action of levamisole, sodium succinate and the positive effect of RNAase on specific resistance in the complex treatment of guinea pigs infected with tuberculosis have been established. On the basis of the pronounced normalization of the systemic and specific resistance characteristics, as well as the clinical effect, the expediency of using levamisole and RNAase in the complex treatment of tuberculosis has been shown.     

Abnormalities in circulating plasmacytoid dendritic cells in patients with systemic lupus erythematosus

Introduction  

Dendritic cells (DCs) are capable of inducing immunity or tolerance. Previous studies have suggested plasmacytoid DCs (pDCs) are pathogenic in systemic lupus erythematosus (SLE). However, the functional characteristics of directly isolated peripheral circulating blood pDCs in SLE have not been evaluated previously.     

Recovery of the cellular immunity system after sublethal radiation

Dynamics and recovery of quantitative and qualitative characteristics of lymphoid tissue were studied after sublethal irradiation. The data obtained are indicative of a different dynamics of recovery of cells in central and peripheral lymphoid organs, GFUs and antibody-forming elements. The peculiarities have been revealed in a change of functional capacity of some T-lymphocyte populations.     

Assessment of the immune status of chronic bronchitis patients in the remission phase during prophylactic treatment with levamisole and staphylococcal vaccine

The work presents the results of the study of the immune status in 18 patients with chronic bronchitis at the stage of remission, subjected to prolonged prophylactic treatment with the inhalations of levamisole solution, and in 16 patients receiving the inhalations of staphylococcal vaccine. These results indicate that the inhalations of levamisole have proved to be more effective than the inhalations of staphylococcal vaccine. In patients treated with levamisole an essential decrease in the ratio of theophylline-resistant to theophylline-sensitive E-rosette-forming lymphocytes has been noted. The determination of the sensitivity of lymphocytes and neutrophils to incubation with levamisole by means of the rosette-formation test makes it possible to prognosticate, taking into account the initial level of spontaneous E-rosette formation of these cells, the effectiveness of the prophylactic treatment of patients with chronic bronchitis. The determination of the sensitivity of the cells to incubation with staphylococcal toxoid is ineffective for the prognostication of the result of the treatment of such patients with staphylococcal vaccine.     

Regulation of human natural killing by levamisole

Summary The effect of levamisole on human natural killing (NK) has been studied. In short-term chromium release assays, levamisole at a concentration of 10^–3 M was inhibitory to NK when present in the assays. Pretreatment of NK effector cells and K562 target cells with levamisole separately indicated that the effect was on effector cell activity and was not due to any change in target cell susceptibility. Inactivation of the effector cells required greater than 4 h pretreatment with levamisole if NK activity was subsequently tested in the absence of the drug. Pretreatment with levamisole for up to 19 h had no effect on the lymphocyte proliferative response to phytohemagglutinin (PHA). NK activity of drug-inactivated effector cells recovered after further incubation in levamisole-free medium. Levamisole at 10^–4 M or less had no effect on NK either by pretreatment or by its presence in the NK assays.     

The antitumor effects of levamisole in mice are mediated by NC-1.1+ cells

 Murine natural cytotoxicity, which is a major component of the innate immune response in cancer, is mediated by leukocytes that express the NC-1.1 receptor. Mice depleted of natural cytotoxicity by treatment with an anti-NC-l.1 mAb show enhanced growth of certain transplantable tumors, so agents that enhance natural cytotoxicity by NC-1.1⁺ cells have the potential to be effective anticancer therapeutic agents. We have examined the immunomodulatory effect of levamisole on natural cytotoxicity mediated by NC-1.1⁺ cells against the BALB/c WEHI-164 murine fibrosarcoma. Administration of levamisole to BALB/c mice significantly enhanced in vitro splenic natural cytotoxicity against ⁵¹Cr-labeled WEHI-164 tumor cells. The effect was most marked 48 h after levamisole treatment, at a dose of 10 mg/kg body weight. This enhancement of natural cytotoxicity by levamisole could be completely abrogated by pretreatment of mice with an anti-NC-1.1 mAb. Treatment of BALB/c mice with 10 mg/kg levamisole significantly reduced the growth of WEHI-164 and this effect was abrogated by pretreatment of mice with anti-NC-1.1, indicating that the antitumor effect of levamisole was mediated, at least in part, via NC-1.1⁺ cells. Received: 5 June 1997 / Accepted: 31 July 1997     

Levamisole regulates the proliferation of murine liver T cells through Kupffer-cell-derived cytokines

 We have previously shown that levamisole increases the cytotoxic, cytostatic, and proliferative activity of murine nonparenchymal liver cells (NPC) in vitro. We have also shown that the nonadherent subpopulation of NPC, which are composed predominantly of T lymphocytes, is very responsive to this agent when administered to mice. Kupffer cells or immigrant macrophages are also responsive to levamisole but to a lesser extent. These findings prompted us to investigate changes in cytokine production by NPC following-treatment of mice with levamisole (25 mg/kg, i.p.), which may help explain the observed alterations in the immune functions of these cells. We found that levamisole treatment of mice causes a threefold increase in production of interferon (IFN) α/β by adherent NPC (more than 80% – 90% Kupffer cells) in vitro. When IFN α/β was added to cultured cells, it decreased the proliferative capacity of liver T cells in a dose-dependent manner. In contrast, the addition of anti-IFNα/β was shown to augment levamisole-induced proliferation of unfractionated NPC and Kupffer cells. NPC production of interleukin 1 (IL-1) and interleukin-6 (IL-6) in vitro was also increased threefold following treatment of mice with levamisole. IL-6 added in vitro to cells significantly augmented levamisole-induced proliferation of liver T cells while anti-IL-6 reduced proliferative activity to control levels. These findings suggested that IFNα/β, IL-6, and IL-1 play important regulatory roles in controlling the proliferative response of murine liver-associated T lymphocytes to levamisole. Finally, the proliferation of bone marrow cells was increased in mice given 5-fluorouracil (5FU). On the other hand, the proliferation of NPC was dramatically suppressed when 5FU was administered. However, the proliferation of these cells was restored when levamisole was given after 5FU. Received: 27 November 1995 / Accepted: 16 October 1996     

Effects of levamisole on hyaluronidase activity and sperm characteristics in rams

The aim of this study was to determine the effects of levamisole on sperm characteristics and hyaluronidase activity of blood serum and semen. For this purpose, 12 Akkaraman rams (2-3 years old) were used. Levamisole hydrochloride was administered orally at a dose of 7.5mg/kg body weights once daily for 2 days. Serum and semen samples were collected from the rams at post-treatment 1, 2, 4, 24, 48, 72, 96, 120, 144, 216, 288 and 384 h and examined for sperm characteristics and hyaluronidase activity. The results showed that the use of levamisole caused significant (P < 0.01) increase in serum hyaluronidase activity at all times except the 72 h, and in semen hyaluronidase activity at 1, 2, 4, 24, 72, 96 and 120 h compared to the control group. In addition, the levamisole caused significant (P < 0.05) decreases in semen volume, sperm motility, concentration and total sperm number at all times. There was no correlation between semen hyaluronidase activity and the sperm characteristics. In conclusion, levamisole did not have any deleterious effect on hyaluronidase enzyme. However, the use of this drug in rams during the breeding season is harmful due to the decrease of sperm characteristics.     

Effects of curvature and cell–cell interaction on cell adhesion in microvessels

It has been found that both circulating blood cells and tumor cells are more easily adherent to curved microvessels than straight ones. This motivated us to investigate numerically the effect of the curvature of the curved vessel on cell adhesion. In this study, the fluid dynamics was carried out by the lattice Boltzmann method (LBM), and the cell dynamics was governed by the Newton’s law of translation and rotation. The adhesive dynamics model involved the effect of receptor-ligand bonds between circulating cells and endothelial cells (ECs). It is found that the curved vessel would increase the simultaneous bond number, and the probability of cell adhesion is increased consequently. The interaction between traveling cells would also affect the cell adhesion significantly. For two-cell case, the simultaneous bond number of the rear cell is increased significantly, and the curvature of microvessel further enhances the probability of cell adhesion.     

Stimulating effect of serum from tumor-bearing mice on lymphocyte response to mitogenic stimulation associated with protein increase in serum

Summary Twenty levamisole-treated and 14 placebo-treated lung cancer patients were studied sequentially in assays of lymphocyte proliferation. Prior to treatment, the patients as a group had significantly depressed proliferative responses to mitogens and allogeneic cells (MLC), and this immunosuppression was especially noticeable in patients with clinically detectable tumor burdens. Following treatment, responses in both levamisole and placebo groups tended to increase slightly, although the increases were more consistent and persistent in the levamisole group. Increases within the levamisole group were similar for patients with and without detectable tumor burdens. Proportions of E and EAC rosette-forming cells were stable throughout treatment for all groups. No consistent response pattern was observed in patients crossed-over from placebo to levamisole treatments. Although these results do not contradict the concept that levamisole can reverse malignancy-induced immunosuppression, levamisole treatment clearly did not result in normalization of lymphocyte-proliferative capacity in these lung cancer patients. The usefulness of a placebo-treated group was apparent, as some increased responsiveness was commonly found with placebo treatment.     

Effect of levamisole and etimisole on the development of experimental allergic encephalomeylitis

A single subcutaneous inoculation with 0.02 mg of heterologous myelin basic protein (MBP) in combination with Freund's complete adjuvant resulted in clinical and histological manifestations of experimental allergic encephalomyelitis (EAE) in 80-90% of treated guinea pigs. Daily parenteral administration of levamisole and etimisole during the latent period produced a suppressive effect on EAE development, reducing morbidity and mortality rates and preventing pathomorphological changes in the CNS. Animals receiving the drugs had decreased delayed hypersensitivity reactions to MBP in vitro. Etimisole brought about a moderate decline in the formation of circulating anti-MBP antibodies, while levamisole did not affect the strength of the humoral response, something which confirmed the primary role of cell-mediated immune reactions in the CNS demyelinization process. The reported findings may be significant in developing therapeutic strategies with respect to demyelinization diseases.     

Utility of a Haemonchus contortus/jird (Meriones unguiculatus) model for studying resistance to levamisole

Trichostrongylid nematodes of sheep commonly are identified as exhibiting resistance to levamisole. In vitro assays have been developed to study levamisole resistance for Haemonchus contortus, but no in vivo model has been identified for this species. To determine the utility of a H. contortus/jird (Meriones unguiculatus) model for examining levamisole resistance, immunosuppressed jirds were inoculated with approximately 1,000 exsheathed infective larvae of H. contortus (resistant or susceptible to levamisole), treated per os on day 10 postinoculation (PI) with levamisole hydrochloride or analogs of the drug, and killed on day 13 PI. Stomachs were removed, opened longitudinally, incubated in distilled water at 37 C for 5 hr, fixed in formaldehyde solution, and stored for subsequent microscopic examination. Doses of levamisole and its analogs, which elicited percentage clearances of greater than or equal to 93.5 for the susceptible strain, cleared less than or equal to 68.9% of the resistant worms. These data are consistent with activities for the drugs against wild-type and levamisole-resistant strains of Caenorhabditis elegans. Thus, the H. contortus/jird model provides a useful in vivo tool to study resistance to levamisole and possibly other anthelmintics.     

Genes affecting the activity of nicotinic receptors involved in Caenorhabditis elegans egg-laying behavior

Egg-laying behavior in Caenorhabditis elegans is regulated by multiple neurotransmitters, including acetylcholine and serotonin. Agonists of nicotinic acetylcholine receptors such as nicotine and levamisole stimulate egg laying; however, the genetic and molecular basis for cholinergic neurotransmission in the egg-laying circuitry is not well understood. Here we describe the egg-laying phenotypes of eight levamisole resistance genes, which affect the activity of levamisole-sensitive nicotinic receptors in nematodes. Seven of these genes, including the nicotinic receptor subunit genes unc-29, unc-38, and lev-1, were essential for the stimulation of egg laying by levamisole, though they had only subtle effects on egg-laying behavior in the absence of drug. Thus, these genes appear to encode components of a nicotinic receptor that can promote egg laying but is not necessary for egg-laying muscle contraction. Since the levamisole-receptor mutants responded to other cholinergic drugs, other acetylcholine receptors are likely to function in parallel with the levamisole-sensitive receptors to mediate cholinergic neurotransmission in the egg-laying circuitry. In addition, since expression of functional unc-29 in muscle cells restored levamisole sensitivity under some but not all conditions, both neuronal and muscle cell UNC-29 receptors are likely to contribute to the regulation of egg-laying behavior. Mutations in one levamisole receptor gene, unc-38, also conferred both hypersensitivity and reduced peak response to serotonin; thus nicotinic receptors may play a role in regulating serotonin response pathways in the egg-laying neuromusculature.     

Immunopotentiation with levamisole in resectable bronchogenic carcinoma: a double-blind controlled trial; Study Group for Bronchogenic Carcinoma.

A long-term multicentre double-blind study was designed to test the immunotropic effects of levamisole in patients undergoing operation for primary bronchial carcinoma. They received levamisole 50 mg three times a day by mouth or placebo for three days every fortnight, starting three days before surgery. Unless there was clinical evidence of recurrence, cytostatic drugs, corticosteroids, and radiotherapy were prohibited. In the 111 patients who have been followed up for one year the incidence of side effects was similar in both groups. Recurrences occurred in 10 out of 51 patients (seven deaths) receiving levamisole and in 20 out of 60 (12 deaths) receiving placebo. Further analysis showed that there were fewer recurrences on levamisole in patients with squamous cell carcinomas and medium and large primary tumours and fewer suspected and proved recurrences and deaths from metastases on levamisole in patients with extended tumours. Distant recurrences tended to be less common with levamisole, whereas the disease-free interval in relapsing patients was almost identical in the two groups. These interim results show that levamisole seems to exert its beneficial effect by preventing immunosuppression due to surgery.     

Assembling neurospheres: dynamics of neural progenitor/stem cell aggregation probed using an optical trap

Optical trapping (tweezing) has been used in conjunction with fluid flow technology to dissect the mechanics and spatio-temporal dynamics of how neural progenitor/stem cells (NSCs) adhere and aggregate. Hitherto unavailable information has been obtained on the most probable minimum time (～5 s) and most probable minimum distance of approach (4-6 μm) required for irreversible adhesion of proximate cells to occur. Our experiments also allow us to study and quantify the spatial characteristics of filopodial- and membrane-mediated adhesion, and to probe the functional dynamics of NSCs to quantify a lower limit of the adhesive force by which NSCs aggregate (～18 pN). Our findings, which we also validate by computational modeling, have important implications for the neurosphere assay: once aggregated, neurospheres cannot disassemble merely by being subjected to shaking or by thermal effects. Our findings provide quantitative affirmation to the notion that the neurosphere assay may not be a valid measure of clonality and "stemness". Post-adhesion dynamics were also studied and oscillatory motion in filopodia-mediated adhesion was observed. Furthermore, we have also explored the effect of the removal of calcium ions: both filopodia-mediated as well as membrane-membrane adhesion were inhibited. On the other hand, F-actin disrupted the dynamics of such adhesion events such that filopodia-mediated adhesion was inhibited but not membrane-membrane adhesion.     

Increased number of intestinal villous M cells in levamisole -pretreated weaned pigs experimentally infected with F4ac+ enterotoxigenic Escherichia coli strain

Immunoprophylaxis of porcine postweaning colibacillosis (PWC) caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 fimbriae is an unsolved problem. Just as ETEC strains can exploit intestinal microfold (M) cells as the entry portal for infection, their high transcytotic ability make them an attractive target for mucosally delivered vaccines, adjuvants and therapeutics. We have developed a model of parenteral/oral immunization of 4-weeks-old pigs with either levamisole or vaccine candidate F4ac⁺ non-ETEC strain to study their effects on de novo differentiation of antigen-sampling M cells. Identification, localization and morphometric quantification of cytokeratin 18 positive M cells in the ileal mucosa of 6-weeks-old pigs revealed that they were: 1) exclusively located within villous epithelial layer, 2) significantly numerous (P< 0.01) in levamisole pretreated/challenged pigs, and 3) only slightly, but not significantly numerous in vaccinated/challenged pigs compared with non-pretreated/challenged control pigs. The fact that levamisole may affect the M cells frequency by increasing their numbers, makes it an interesting adjuvant to study development of an effective M cell-targeted vaccine against porcine PWC.Key words: M cells, levamisole, E. coli vaccine, weaned pigs.     

Specific antigens of the causative agents and their antibodies in the circulating immune complexes in acute dysentery

The level of circulating immune complexes has been determined in 53 patients in the dynamics of the disease. For the first time circulating immune complexes have been found to contain Shigella sonnei K-antigen and Shigella flexneri O-antigen, as well as IgA, IgG and IgM to Shigella. Shigella antigens can be detected from the first week of the disease, and their occurrence does not depend on the level of circulating complexes in patients blood serum.     

Immunological aspects of a space flight to Mars

The effects on the immune system of a 520-day isolation in a confined environment, simulating some conditions of a manned space flight to Mars, have been studied. A set of signs of adaptational reorganization, including quantitative and functional changes in innate and adaptive immunity, have been recorded. The most significant ones include the changes in the system of Toll-like receptors (TLRs) manifested as a decrease in the content of circulating monocytes and granulocytes expressing TLR2, TLR4, and TLR6; a decrease in the functional capacity of cellular factors of natural cytotoxicity or natural killer cells (NK cells); an increased ability of T cells and B cells to express on their surface the CD69 early activation marker; and an increase in phytohaemagglutinin (PHA)-induced secretion by cytokines in peripheral blood mononuclear cells. Intense mobilization of adaptive immunity and qualitative changes of its functions demonstrates the adaptive adjustment of the body in response to the combined effect of unfavorable factors to preserve immune homeostasis.