Stimulation of hemopoietic colony formation from mouse marrow cells in vitro using human dialyzable leukocyte extracts-IMMODIN-SEVAC

In VitroAntibacterial Activity of Bovine Dialyzable Leukocyte Extract

The rapidly developing resistance of many infectious pathogenic organisms to modern drugs has spurred scientists to search for new sources of antibacterial compounds. One potential candidate, bDLE (dialysis at 10 to 12 kDa cut-off) and its fractions ("S" and "L" by 3.5 kDa cut-off and I, II, III, and IV by molecular exclusion chromatography), was evaluated for antibacterial activity against pathogenic bacterial strains (Staphylococcus aureus, Streptococcus pyogenes, Lysteria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) using standard antimicrobial assays. A minimum inhibitory concentration (MIC) of bDLE and its fractions was determined by agar and broth dilutions methods. Only bDLE and its "S" fraction had an effect upon all bacteria evaluated (MIC ranging from 0.29 to 0.62 U/ml), and the bactericidal and bacteriostatic effects (evaluated by MTT assay) were bacterial species-dependent. These results showed a remarkable in vitro antibacterial property of bDLE against several pathogenic bacteria.

Ultrafiltered Pig Leukocyte Extract (UPLE, IMUNOR®) Potentiates Hematopoiesis–Stimulating Effects of G-CSFIn Vitroand Improves the Outcome of Treatment of Hematopoietic Radiation Damage in Mice with G-CSF

Ultrafiltered pig leukocyte extract (UPLE, Imunor), a heterogeneous mixture of low molecular weight (<10 kD) substances released from disintegrated pig leukocytes was tested from the point of view of its hematopoiesis-modulating activities using experiments in vitro and in vivo. Attention was focused especially on evaluation of the contingent ability of UPLE to potentiate the hematopoiesis-stimulating effects of recobinant human granulocyte colony-stimulating factor (G-CSF). Experiments in vitro revealed the capability of sera from mice administered UPLE perorally (p.o.) to stimulate proliferation of progenitor cells for granulocytes and macrophages (GM-CFC) in cultures of normal bone marrow cells. In addition, UPLE, as well as sera from mice given UPLE, added to the cultures in combination with G-CSF enhanced the numbers of GM-CFC significantly over those induced by sera after administration of either of the preparations alone. In in vivo experiments, UPLE was found to increase the counts of GM-CFC per femur and femoral bone marrow cellularity in sublethally irradiated mice when administered p.o. after irradiation in combination with G-CSF in comparison with the effects of G-CSF alone. These results indicate the possibility of using UPLE, a commercially available preparation, for treatment of hematopoietic suppression of various etiology.

The role of G-CSF and IL-6 in the granulopoiesis-stimulating activity of murine blood serum induced by perorally administered ultrafiltered pig leukocyte extract, IMUNOR®

IMUNOR, a low-molecular weight (< 12 kD) ultrafiltered pig leukocyte extract, has been previously found to have significant stimulatory effects on murine hematopoiesis supressed by ionizing radiation or cytotoxic drugs. This communication shows data on the mechanisms of these effects. Using ELISA assay, significantly increased levels of granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) were observed. On the contrary, no detectable levels of granulocyte-macrophage colony-stimulating factor (GM-CFC) and interleukin-3 (IL-3) have been found in blood serum of IMUNOR-treated mice. Incubation of the serum from IMUNOR-treated mice with antibodies against G-CSF caused abrogation of the ability of the sera to stimulate in vitro growth of colonies originating from granulocyte-macrophage progenitor cells (GM-CFC). In contrast, incubation of the serum with antibodies against IL-6 did not change its colony-stimulating activity. It may be inferred from these findings that G-CSF is probably the main cytokine responsible for the granulopoiesis-stimulating effects of IMUNOR. When the serum from IMUNOR-treated mice with G-CSF inactivated by anti-G-CSF antibodies (but with elevated IL-6) was added to cultures of bone marrow cells together with a suboptimum concentration of IL-3, a significant increase in the numbers of GM-CFC colonies was found. Moreover, conjoint inactivation of G-CSF and IL-6 significantly decreased the numbers of GM-CFC colonies in comparison with those observed when only G-CSF was inactivated. This observation strongly suggests that though IMUNOR-induced IL-6 is not able to induce the growth of GM-CFC colonies alone, it is able to potentiate the hematopoiesis-stimulating effect of IL-3. These findings represent a new knowledge concerning the hematopoiesis-stimulating action of IMUNOR, a promising immunomodulatory agent.

Peroral IMUNOR, a low-molecular-weight immunomodulator prepared from disintegrated and ultrafiltered leukocytes, enhances recovery from myelosuppression induced by cisplatin or 5-fluorouracil

A single dose of IMUNOR, a low-molecular-weight immunodulator prepared from disintegrated and ultrafiltered pig leukocytes, was found to enhance recovery of murine pool of hemopoietic progenitor cells for granulocytes and macrophages damaged by a single injection of cytotoxic drugs 5-fluorouracil or cisplatin. The best results were obtained after the treatment with IMUNOR on days 3 or 4 after the injection of 5-fluorouracil or cisplatin. These results together with previous findings obtained in our laboratory suggest that IMUNOR has the potential to become a part of treatment schemes in oncological practice aimed at alleviation of myelosuppression evoked by cytotoxic anti-tumor therapy.

Hemopoiesis-stimulating effects and enhanced survival of irradiated mice after peroral or intraperitoneal administration of ultrafiltered pig leukocyte extract (UPLE, IMUNOR)

Ultrafiltered pig leukocyte extract (UPLE, IMUNOR, ImunomedicA, Ustí nad Labem, Czech Republic) administered perorally (p.o.) or intraperitoneally (i.p.) enhanced recovery of the pool of granulocyte-macrophage hemopoietic progenitor cells (GM-CFC) in the bone marrow of normal or sublethally irradiated mice and increased survival of mice exposed to a lethal radiation dose. In experiments in vitro, sera of mice treated with UPLE p.o. or i.p. induced GM-CFC colony formation in cultures of normal mouse bone marrow cells, i.e., produced colony-stimulating activity (CSA). UPLE alone did not induce GM-CFC colony growth, i.e., had no CSA. When UPLE alone or sera of mice administered UPLE p.o. or i.p. were added to bone marrow cultures containing suboptimal concentration of recombinant mouse interleukin-3 (rmIL-3), both UPLE and the sera increased the counts of GM-CFC colonies in comparison with cultures containing only rmIL-3, i.e., produced co-stimulating activity (CoSA). Based on the findings obtained in vitro, it can be hypothesized that the described CSA and CoSA of UPLE may play a role also under in vivo conditions; enhancement of the recovery of hemopoiesis suppressed by ionizing radiation may be due to co-operation of the stimulatory effects of UPLE with the action of cytokines endogenously produced in irradiated tissues.

Positive effects of dialyzable leukocyte extract (DLE) on recovery of mouse haemopoiesis suppressed by ionizing radiation and on proliferation of haemopoietic progenitor cells in vitro

Dialyzed leukocyte extract (DLE) (Immodin SEVAC, Czech Republic) was shown to enhance the recovery of the pools of hemopoietic stem cells (CFUs) and of granulocyte-macrophage hemopoietic progenitor cells (GM-CFC) in the bone marrow in vivo, as well as to increase the numbers of leukocytes and thrombocytes in the peripheral blood of mice exposed to a sublethal dose of gamma-rays, with an ensuing increase in the numbers of mice surviving the lethal radiation dose. In experiments performed in vitro, DLE or sera of mice administered with DLE were added to cultures of intact mouse bone marrow cells containing suboptimal concentrations of hemopoietic stimulatory cytokines, namely recombinant mouse interleukin-3 (rmIL-3) or recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF); under these experimental conditions, both DLE and sera of mice administered DLE were found to increase the counts of GM-CFC colonies in the cultures. It can be hypothesized on the basis of the findings obtained in vitro that the described co-stimulating activity (CoSA) of DLE may play a role also under in vivo conditions; the enhancement of the recovery of hemopoiesis suppressed by ionizing radiation may be due to a co-operation of the stimulatory effects of DLE with the action of cytokines endogenously produced in irradiated tissues.