[The effect of platelet-activating factor and its antagonist--BN 52021--on immune reactions in vivo in mice and in vitro]

The effect produced by the injection of platelet activation factor (PAF) and its antagonist BN 52021 on the intensity of humoral immune response in (CBA x C57BL)F1 mice was studied. PAF was found to stimulate the formation of antibodies to sheep red blood cells. In addition PAF stimulated the phagocytic activity of mouse peritoneal macrophages. The stimulation of immune response under the action of PAF may be attributed to an increase in the phagocytic activity of macrophages. The stimulating effect of PAF on immune response in vivo was abolished by the injection of BN 52021, the antagonist of PAF. At the same time the dose-dependent decrease of immune response was observed after the injection of BN 52021. Indomethacin, an inhibitor of prostaglandin synthesis, when administered to mice treated with BN 52021, abolished the BN 52021-induced suppression of humoral immune response. Mouse peritoneal macrophages, treated in vitro with BN 52021, were found to produce significantly more prostaglandin E than control macrophages. Thus, BN 52021 induced the suppression of humoral immune response in vivo; this suppression was probably due to the action of prostaglandin E2, a messenger of the second order. Besides, the PAF antagonist BN 52021 significantly decreased leukotriene B4 production by macrophages in vitro. BN 52021 may be supposed to switch over the synthesis and/or secretion of arachidonic acid from the lipoxygenase pathway to the cycloxygenase one.

[Immuno- and erythropoiesis in mice with graft vs host disease against a background of immunodeficiency]

In BALB/c mice immunodeficiency was induced by the transfer of lymphocytes immune to alloantigen. This model is one of experimental models of AIDS. The work was aimed at the study of disturbances in the immuno--and erythropoiesis in immunodeficient mice. The state of erythropoiesis was evaluated by the level of level of hemoglobin, hematocrit and the content of reticulocytes in peripheral blood, by the number of erythroid bursitis-forming units and the percentage of erythrokaryocytes in the marrow, as well as by the number of colony-forming units in the spleen by days 5 and 8. The study revealed that in BALB/c mice hypoplastic anemia, accompanied by the decreased phagocytic activity of macrophages and the reduced production of interleukin 1 and tumor necrosis factor, developed on months 5-6 of the disease. Macrophagal dysfunction was supposed to be one of the causes of hypoplastic anemia in immunodeficient mice.

Technique for continuous tuning of optical fiber lasers

For the first time to the authors' knowledge, we have demonstrated how thermally controlled overcoupled fused fiber couplers and fiber loop mirrors based on these couplers can be used as broadband tuning elements in a fiber laser cavity. No bulk optical elements play any role in this technique. Temperature tuning the coupler results in a shift in the coupling ratio or in the effective output coupler transmission. For a fixed pump source, and for a given laser cavity, this shift causes the lasing wavelength to shift. We have continuously tuned an Er silica fiber laser in this manner over the range of 1527-1570 nm in a ring configuration, and, using a fiber loop mirror with these couplers in a linear Tm silica fiber laser cavity, we have achieved more than 50-nm broadband tuning over the range of 1850-1910 nm. The tuning range and the sensitivity to temperature depend on the degree of overcoupling of the loop mirror coupler.

Production of Peptide of Retroviral Origin in Sera of Patients with Chronic Myeloid Leukemia at Acute Phase

In the present study we investigated production of the peptide of retroviral origin in patients with various types of leukemia. For this purpose the high affinity rabbit antibodies were generated against the synthetic peptide representing the "immunosuppressive motif" within the envelope protein of human endogenous retrovirus type C. The presence of this peptide was identified only in sera of the patients with chronic myelo- and/or promonocytic leukemia at acute phase. Furthermore, the appearance of this protein correlated with agranulocytosis. SDS-PAGE profile revealed the serum protein recognized by Ab that had MW of 88 kDa. However, in bone marrow cells, the same Ab bound 66 kDa peptide, and low molecular weight peptide, INF-agr;, as well. It was determined that 88 kDa protein was a highly glycosylated version of 66 kDa protein. Staining blood cells and bone marrow cells with FITC-labelled specific monoclonal antibodies demonstrated that CD34(+) cells produced this peptide. The appearance of this peptide in sera of patients with myeloid leukemia was considered as unfavorable prognosis since it was followed with lethality in 50% of cases. Thus, besides potential involvement of endogenous retroviral products in carcinogenesis, they may be considered as a factor of immunosuppression.

[The mathematical modelling and computation of the stressed-deformed state of metal-ceramic dentures]

The SPLEN-K (INZOMA) computing system, based on the mathematical model of a heterogeneous elastic body with linear plastic reinforcement helps estimate the design of coated dentures with due consideration for the individual features of the jaws and teeth, articulation, and occlusion. The open module type of this system permits its modifications and improvements, allows introduction of individual changes in the planned denture design, helps rapidly estimate the changes in the strained-deformed state and assess the correctness of the result from the computed data. The reliability of estimations was assessed in special tests. Practical results of theoretical studies are adequate to clinical and experimental data.

Characterization of erythroid cell-derived natural suppressor activity

Nucleated erythroid cells (NEC) have been previously reported to the capable of suppressing antibody-mediated primary (IgM) and secondary (IgG) immune responses to thymus-dependent antigens. In the present study we indicated that NEC, separated from the spleens of mice following phenylhydrazine treatment were able to suppress directly the proliferative response of preactivated B cells to lipopolysaccharide (LPS) in vitro. While being active in suppressing B cell blastogenesis, NEC, however, failed to reduce both cell proliferation and cytotoxic T lymphocyte (CTL) generation in an allogeneic mixed lymphocyte culture (MLC). NEC also lacked a significant effect on interleukin (IL)-2 production and utilization by concanavalin A (Con A)-activated T lymphocytes. The NEC-derived suppression of B cell proliferation was, at least in part, mediated by soluble molecules. The specific blockade of transforming growth factor (TGF)-beta synthesis with antisense oligodeoxynucleotides (OD) binding TGF-beta mRNA, as well as the neutralization of TGF-beta activity with anti-TGF-beta antibodies (Ab), resulted in a detectable diminished ability of the NEC-conditioned medium (CM) to suppress B cell blastogenesis. Taken together, the results suggest that: 1) NEC may suppress directly B cell responses, while not affecting T cell ones; 2) NEC may mediate their natural suppressor (NS) activity partially through releasing TGF-beta.

IL-2-Activated Killer Cells and Native Cytokines in Treatment of Patients with Advanced Cancer

We evaluated the efficiency/tolerability of and the immunological changes induced by the adoptive immunotherapy (AIT) with IL-2-activated killer cells, and preparation of native cytokines from swine spleen (PSS) in treatment of 20 patients with advanced cancer (10 patients with primary lung cancer; 3 with metastatic melanoma; 2 with advanced neuroblastoma; 2 with ovarian cancer; renal cancer; gastric adenocarcinoma; and colorectal cancer). The partial/minor response of duration period 2-10 months was observed in 20% of patients. 2/4 patients, who underwent partial surgical tumor resection and following AIT course, sustained the event-free survival for more than 24 months. The response to the therapy was revealed in 4/10 patients with lung cancer, 2/2 patients with neuroblastoma, of whom each had ovarian and colorectal cancers. The evaluation of a dose of infused LAKcells as well as combined i.v./local (endobronchial or endoperitoneal) LAK administration were necessary to assure positive response in patients. The cytokine and/or side effects were moderate and the combined LAK-PSS infusions were generally well tolerated by the patients. The treatment was followed by activation of the patient immune system that included: (i) rebound in amount of peripheral blood lymphocytes; (ii) gain in amount of CD3(+) T cells and those CD4(+) helper/inducer; (iii) enchantment of lymphocyte proliferation and cytokine production (IL-2, IL-1, TNF-alpha). Being injected to patients in combination with LAK cells, cytokines related to PSS action and/or those, either exogenous or secondary, and released by in vitro and in vivo, activated lymphocytes and could cause the therapeutic effects.

Tumor growth inhibitory and natural suppressor activities of murine bone marrow cells: a comparative study

The murine bone marrow (BM) cells having a certain phenotypic similarity to null natural suppressor (NS) cells have been previously established to be able to inhibit in vitro leukemic cell growth in a genetically unrestricted manner. In this study we found that the treatment of normal (C57BL/6 x DBA)F1 BM cells with a lysosomotropic agent, L-leucine methyl ester (LME), largely abrogated their ability to reduce both P815 mastocytoma and L1210 lymphoma cell proliferation, as well as their NS activity tested for suppression of mitogen (Con A or LPS)-driven spleen cell proliferation. However, after being depleted of the cells binding wheat germ agglutinin (WGA), the BM cells maintained tumor growth-inhibitory activity, while demonstrating no significant NS activity. Moreover, in contrast to T-cell blastogenesis-inhibitory NS activity of BM cells, that was greatly reduced by the addition into the culture of either neutralizing anti-interferon (IFN)-gamma antibody (Ab) or NG-monomethyl-L-arginine, a competitive inhibitor of NO synthase, natural antitumor cytostatic activity of BM cells was not found to be dependent on the presence in medium of IFN-gamma and to be associated with NO production. When incubated at suboptimal numbers with tumor cells on conic, round, and flat well bottoms for 7 h, BM cells provided the most, middle, and least (or no) tumor growth inhibition, respectively, suggesting, thereby, a significance of cell density in cytostatic process. It was also found that the BM cells cultured for 20 h with the medium conditioned by mitogen-preactivated T or B lymphocytes were significantly more suppressive to tumor cell proliferation than the BM cells cultured in medium alone. The potentiation of BM-cell cytostatic activity by T-cell-conditioned medium (CM), but not that by B-cell-CM, was found to be partially reversed by anti-IFN-gamma Ab. Finally, a noticeable tumor growth-inhibitory activity, which could be significantly enhanced upon T-cell-CM, was shown to be also attributable to BM cells from athymic BALB/c mice. Taken together, the results suggest that (1) the tumor growth inhibitory BM cells and the NS BM cells are not identical in their cell compositions, but also differ in their mechanisms of antiproliferative action; (2) a contact cell-to-cell interaction may play a significant role in BM-cell-mediated tumor growth inhibition; (3) the activated lymphocytes, through both IFN-gamma-mediated and IFN-gamma-independent pathways, are able to operatively up-regulate the cytostatic activity of BM cells; and (4) the tumor growth-inhibitory activity exhibited by the normal unmanipulated BM cells, at least in its significant part, may not be a consequence of thymus-dependent immune processes occurring normally in the body.

Induction of mixed allogeneic chimerism for leukemia

Hybrid (C56BL/6 x DBA) (BDF1; H-2b/H-2d) mice bearing the P815 leukemia (H-2d) were grafted with a (CBA x C57BL/6)F1 (CBF1; H-2k/H-2b) cell suspension, comprising bone marrow cells (BMC; 25 x 10(6)/mouse) and spleen cells (SC; 55 x 10(6)/mouse) on day-4, then treated with cyclophosphamide (200 mg/kg) on day-2 and finally grafted once more with CBF1 cells (25 x 10(6) BMC + 7 x 10(6) SC) on day 0. Allogeneic cell graftings performed in this way induced durable mixed hematopoietic chimerism and significantly prolonged the survival of recipients, compared with that of leukemia-bearers grafted with syngeneic cells. The results obtained raise the possibility of using allogeneic hematopoietic tissue transplantation in combination with non-lethal cytoreductive therapy to induce a long-lasting graft-vs-leukemia effect.

[The use of antisense oligonucleotides for modulation of cytokine gene expression]

The review summarizes literature data on the mechanism of action and the use of antisence oligonucleotides for modulation of cytokine gene expression in haemo- and immunopoesis. This new approach for gene-directed modulation of the gene expression allows to analyze both intercellular and intracellular protein interaction. Use of this approach is prospective for both experimental researches in vivo and in vitro and application in therapeutic purposes.

A role for interferon-gamma and transforming growth factor-beta in erythroid cell-mediated regulation of nitric oxide production in macrophages

Interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) are known to be a potent inducer and inhibitor for macrophage (Mo) activation process, respectively. In the present study we established that the nucleated erythroid cells (NEC) separated from the spleens of adult (CBA x C57BL/6)F1 (CBF, H-2k/H-2d) mice following phenylhydrazine treatment are potentially capable of inducing nitric oxide (NO) production in thioglycollate broth-elicited peritoneal macrophages (Mo). The stimulating effect of both NEC and their culture supernatant on NO secretion by Mo was most apparent in the presence of bacterial lipopolysaccharide (LPS) and neutralizing antibodies (Abs) to TGF-beta and was largely reversed by the addition to the culture of neutralizing Abs to IFN-gamma. Collectively these results suggest that NEC, through production of IFN-gamma and TGF-beta, may exert a regulatory influence on development and functionality of cells pertaining to monocyte (Mc)/Mo lineage.

Cytokine gene expression in erythroid cells

Erythroid nuclear cells have been shown to exert regulatory effects on immunopoiesis. We have reported that some of these influences might be mediated via soluble factors secreted by nuclear erythroid cells. In this report we describe our estimate of the cytokine gene expression in cells isolated from individual erythroid colonies by Reverse transcription-Polymerase chain reaction. We found in erythroid cells, originated from the bone marrow precursors obtained from phenylhydrazine-treated mouse, the expression of the following cytokine genes: IL-1 alpha and IL-1 beta, IL-4, IL-6, GM-CSF, gamma-IFN and TGF-beta. In contrast, the erythroid cells derived from newborn mouse spleen precursor cells expressed IL-1 alpha, IL-1 beta, IL-4, IL-6 and GM-CSF mRNAs but not gamma-IFN and TGF-beta mRNAs. No detectable levels of IL-2, IL-3 and IL-5 mRNAs were expressed in nuclear erythroid cells. These data provide evidence of the expression of mRNAs coding in the set of immunoregulatory cytokines in immature erythroid progenitor cells in mouse.