Granulocyte colony-stimulating factor downregulates interferon-gamma receptor expression and stimulates interleukin-6 production in activated human macrophages.

We studied direct effects of human granulocyte colony-stimulating factor (G-CSF) on phenotypical properties of human macrophage cells in vitro. CD14+ monocyte/macrophages (Mc/Mphs) were isolated from blood of healthy donors by positive magnetic separation. G-CSF (0.01-1.0 ng/mL), when added to Mc/Mphs along with lipopolysaccharide (LPS, 1.0 µg/mL), was able to noticeably reduce proportions of CD119 (interferon-γ receptor 1)-positive cells, with no stable effects on CD16 (FcγRIII)+ and СD124 (IL-4 receptor subunit alpha)-positive cells. In addition, G-CSF markedly upregulated IL-6 production by LPS-activated Mph cells, without significantly affecting IL-1ß, IL-10 and tumor necrosis factor-α (TNF-α) secretion. Our data suggests that G-CSF could restrain Mph polarization to pro-inflammatory (M1) phenotype, thus potentially supporting pro-regenerative Mph activity with implications for immunotherapeutic interventions.

Dexamethasone effects on activation and proliferation of immune memory T cells.

Dose-dependent effects of dexamethasone on activation and proliferation of donor immune memory T cells (CD45RO(+)) were studied. Activation of memory T cells associated with IL-2 production and membrane expression of CD25 molecule was resistant to dexamethasone. Proliferative activity of memory T cells associated with membrane expression of CD71 molecule was highly sensitive to dexamethasone. Hence, glucocorticoid hormones can maintain the clonal balance in the lymphoid tissue without preventing realization of the immune memory mechanism.

[The impact of surgical correction of obesity (laparoscopic gastro-bypass surgery) under metabolic syndrome on the biochemical blood indicators].

In nowadays the wide propagation of surgical treatment of metabolic syndrome using the laparoscopic gastro-bypass surgery can be explained hy severe consequences of clinical manifestation of metabolic syndrome. The risk of the mentioned method has to be clear-cut assessed. The comprehensive analysis of changes in indicators of metabolism has to be applied to patients with metabolic syndrome before and after laparoscopic gastro-bypass surgery. The study was carried out on the sampling of 41 patients, 16 patients before and 25 after laparoscopic gastro-bypass surgery. In patients with metabolic syndrome after laparoscopic gastro-bypass surgery the normalization of concentration of glucose and glycated hemoglobin was established. The level of triglycerides, low density lipoproteins and reactive protein reliably decreased as compared with indicators of in non-operated patients. After laparoscopic gastro-bypass surgery, the positive dynamics of activity of enzymes of blood serum was noted.

Delayed results of transplantation of fetal neurogenic tissue in patients with consequences of spinal cord trauma.

We analyzed delayed effects of transplantation of nervous and hemopoietic fetal cells to patients with consequences of spinal trauma. A decrease in neurological deficit associated with pronounced improvement of functional independence was observed in 48.9% cases. The best results were observed in patients receiving cell transplantation within the first 2 years after trauma and in younger individuals. The pattern of morphological changes in the spinal cord at site of injury, severity of damage, and the method of transplantation had no appreciable effects on its delayed results.

Xenogeneic cell-based vaccine therapy for colorectal cancer: Safety, association of clinical effects with vaccine-induced immune responses.

An accumulating body of evidence suggests that xenogeneic vaccines can be very effective in breaking the immune tolerance to human tumor-associated antigens (TAAs). We assessed adverse effects, as well as clinical and immune responses induced by a lyophilized xenogeneic polyantigenic vaccine (XPV) prepared from murine melanoma B16 and carcinoma LLC cells in 60 stage IV colorectal cancer patients. Neither grade III/IV toxicities, nor laboratory and clinical signs of systemic severe autoimmune disorders were documented in any XPV-treated patient. Clinical effects of various grades (complete response, partial response and disease stabilization) with duration of no shorter than 6 months was observed in 25 (41.67%) vaccinated patients. The average survival time of the XPV-treated patients was markedly longer than that of the clinically matched control patients (20 vs. 7 months). The overall 3-year survival rate in the XPV-treated and control group was 16.7% (10 patients) and 0%, respectively. Following a course of ten XPV vaccinations, peripheral blood mononuclear cell (PBMC) proliferation assays revealed increased T-cell immune responses to human Caco-2 colon adenocarcinoma-associated antigens. In addition, relative contents of CD25+ FoxP3+regulatory T-cells in patients with proven immunotherapy-mediated clinical effects (responders) were significantly decreased in the blood, which was paralleled by marked increases in serum levels of proinflammatory cytokines, such as interferon-alpha (IFN-α), IFN-É£, and interleukin-8 (IL-8). Serum levels of tumor necrosis factor-alpha (TNF-α), IL-1, IL-4, and IL-6 were not affected in both responder and non-responder patients. In conclusion, this study provides evidence for the safety, clinical feasibility and immunogenicity of xenogeneic composite cell vaccine administration in colorectal cancer patients. This is the first demonstration that clinical effects of such a vaccine are associated with vaccine-induced, proinflammatory immune responses.

[DIRECT EFFECT OF IL-7 ON THE GROWTH AND FUNCTIONAL ACTIVITY OF T-LYMPHOCYTES IN THE ABSENCE OF ANTIGENIC STIMULUS].

It is shown that in the absence of antigenic stimulus interleukin-7 (IL-7) is capable of increasing the content of cells expressing the CD25 molecule among both CD4-positive and CD4-negative effector memory T-cells (CD45RA-CD197-), as well as terminally differentiated T cells (CD45RA+CD197-) without causing a significant impact on the status of the activation of naive T cells (CD45RA+CD197+) and central memory T cells (CD45RA-CD197+). IL-7 was also able to enhance T-cell production of IL-2, interferon-γ (IFN-γ) and IL-10, but not IL-4. These data indicate the involvement of IL-7 into a direct upregulation of growth and functional activity of human T cells in the absence of antigenic stimulus and the relative scarcity of costimulatory effects.

Erythropoietin exerts direct immunomodulatory effects on the cytokine production by activated human T-lymphocytes.

The effect of erythropoietin-ß (Epo-ß) on the functional profile of activated human T-lymphocytes remains largely unknown, which hinders clinical application of Epo as an immunomodulatory agent. We studied the direct impact of Epo on the activation status of human T lymphocytes following activation by particles loaded with antibodies (Abs) against human CD2, CD3, and CD28. T cell activation was assessed by the surface expression of CD38 activation marker. Epo did not significantly affect activation status of both CD4(+) and CD4(-) T cells, as well as of naive (CD45RA(+)CD197(+)), central memory (CD45RA(-)CD197(+)), effector memory (CD45RA(-)CD197(-)), and terminally-differentiated (CD45RA(+)CD197(-)) T cells. However, Epo markedly augmented production of IL-2, IL-4 and IL10 by activated T cells with concomitant reduction in IFN-γ secretion. Taken together, our data showed that Epo could directly down-regulate pro-inflammatory T cell responses without affecting T cell activation status.

Erythroid cells in suppressing leukemia cell growth.

This paper indicates that murine nucleated erythroid cells (EC) are able to reduce, in a dose-dependent manner, the proliferation of both L1210 lymphoma and P815 mastocytoma cells and that the leukemia cell growth inhibitory activity of unseparated bone marrow (BM) cells may be markedly augmented by their short-term culturing with erythropoietin (Epo). These results raise the intriguing possibility to utilize erythropoesis-stimulating, therapeutic strategies with the purpose of inhibiting leukemia cell growth in the body.

[Psychological and immunological defenses in cancer--the two aspects of one problem].

The study group included 17 cancer patients, aged 25-55, (stage III-IV), mostly suffering melanoma. All of them received hypnosuggestive therapy to correct psycho-emotional disorders. Significant decrease in anxiety-related indices (p < 0.001) due to therapy pointed to rehabilitation of psychological defenses. Clinical rehabilitation was manifested by improved quality of life (p < 0.01), better habitus and adaptation (p < 0.01). The modulating effect on the macrophageal and phagocytic components of the immune system (p < 0.05) was matched by a significant correlation between psychological defense indices and those of immunological status. Our data have contributed to the existing knowledge about relationships of mind and immunity in cancer patients.

Multiple-purpose immunotherapy for cancer.

Anti-cancer vaccination is a useful strategy to elicit antitumor immune responses, while overcoming immunosuppressive mechanisms. Whole tumor cells or lysates derived thereof hold more promise as cancer vaccines than individual tumor-associated antigens (TAAs), because vaccinal cells can elicit immune responses to multiple TAAs. Cancer cell-based vaccines can be autologous, allogeneic or xenogeneic. Clinical use of xenogeneic vaccines is advantageous in that they can be most effective in breaking the preexisting immune tolerance to TAAs. An attractive protocol would be to combine vaccinations with immunostimulating and/or immunosuppression-blocking modalities. It is reasonable to anticipate that combined immunotherapeutic strategies will allow for substantial improvements in clinical outcomes in the near future.

Clinically feasible approaches to potentiating cancer cell-based immunotherapies.

The immune system exerts both tumor-destructive and tumor-protective functions. Mature dendritic cells (DCs), classically activated macrophages (M1), granulocytes, B lymphocytes, aß and ɣδ T lymphocytes, natural killer T (NKT) cells, and natural killer (NK) cells may be implicated in antitumor immunoprotection. Conversely, tolerogenic DCs, alternatively activated macrophages (M2), myeloid-derived suppressor cells (MDSCs), and regulatory T (Tregs) and B cells (Bregs) are capable of suppressing antitumor immune responses. Anti-cancer vaccination is a useful strategy to elicit antitumor immune responses, while overcoming immunosuppressive mechanisms. Whole tumor cells or lysates derived thereof hold more promise as cancer vaccines than individual tumor-associated antigens (TAAs), because vaccinal cells can elicit immune responses to multiple TAAs. Cancer cell-based vaccines can be autologous, allogeneic or xenogeneic. Clinical use of xenogeneic vaccines is advantageous in that they can be most effective in breaking the preexisting immune tolerance to TAAs. To potentiate immunotherapy, vaccinations can be combined with other modalities that target different immune pathways. These modalities include 1) genetic or chemical modification of cell-based vaccines; 2) cross-priming TAAs to T cells by engaging dendritic cells; 3) T-cell adoptive therapy; 4) stimulation of cytotoxic inflammation by non-specific immunomodulators, toll-like receptor (TLR) agonists, cytokines, chemokines or hormones; 5) reduction of immunosuppression and/or stimulation of antitumor effector cells using antibodies, small molecules; and 6) various cytoreductive modalities. The authors envisage that combined immunotherapeutic strategies will allow for substantial improvements in clinical outcomes in the near future.

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.

Antiproliferative effect of bone marrow cells on leukemic cells.

When normal murine bone marrow (BM) cells were cultured with either L1210 lymphoma cells or P815 mastocytoma cells for 24 h, considerable tumor growth suppression without substantial tumor cell lysis was found. Under the same conditions, normal spleen cells also demonstrated the antitumor cytostatic activity, but not as significant as that characteristic of BM cells, whereas both normal thymus and lymph node cells had not any suppressive effect on tumor cell proliferation. The comparable cytostatic effects occurred in both syngeneic and allogeneic BM-tumor cell combinations. The cytostatic BM-effectors were distinct from T and B lymphocytes or mature macrophages. After being separated on a discontinuous Percoll density gradient, the cells active in suppressing tumor growth were recovered predominantly in 1.075 and 1.060 density fractions. The cytostatic BM effectors, at least in their part, were resistant to x-irradiation up to 2000 rad included. Collectively these results suggest that normal BM, being deficient in cell-mediated antitumor cytolytic activity, has a significant leukemia growth inhibitory potential; and that cytostatic BM effectors are similar in their characteristics to natural suppressor cells.

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.

An 'antigenic ligand competition' model for antigen receptor-mediated lymphocyte selection.

The 'antigenic ligand competition' model advanced herein represents a principally novel view on lymphocyte selection, postulating a leading role in this process of competition between different determinants expressed on self ligands for binding to antigen receptors. Based on the data indicating that cell viability and cell growth are separately regulated processes, it is speculated that the binding of antigenic receptors with monovalent determinants (MDs) expressed on soluble self ligands may be responsible for lymphocyte survival, whereas the moderate (but not hyper) cross-linking of antigenic receptors with polyvalent determinants (PDs) expressed on other or the same self ligands may provide signalling that is necessary to trigger lymphocyte proliferation. In the light of the model, the lymphocytes whose receptors bind with high affinity to self MDs survive, while not receiving a proliferative stimulus. On the other hand, those lymphocytes whose receptors interact with high affinity with self PDs and consequently undergo hypercross-linking die by apoptosis. Lastly, those lymphocytes whose receptors interact simultaneously with both MDs and PDs in a balanced competitive manner receive both viability and a proliferative stimulus and, as a consequence, it is only they which obtain selective advantage. The balanced competition between self MDs and self PDs for receptor binding seems likely when the receptors have relatively low affinity to such determinants inasmuch as the opposite, namely comparably high specificity (affinity) to structurally distinct determinants, is unlikely. Essentially, the model presented herein also suggests that a balance between distinct antigenic determinants occupying antigen receptors may determine not only self antigen-driven lymphocyte selection, but also immune reactivity of the functionally mature B- and T-cells which have passed through this selection.

Triggering effects of BCG vaccine on antitumor and interleukin-1 secretory activity of T cell lymphokine-primed macrophages.

By using an in vitro model, this work demonstrates that BCG (Bacillus Calmette-Guerin) vaccine is able to trigger activation of T cell lymphokine-primed murine macrophages (Mo) for both tumoricidal cytotoxicity and interleukin-1 (IL-1) secretion. The results presented support the view that BCG vaccine may essentially activate primed, but not intact Mo; and that macrophage-mediated both antitumor and immunostimulatory effects of BCG vaccine observed in the body may be largely defined by functional activity of T-lymphocytes responsible for antigen-induced production of macrophage-activating lymphokines.

Bone marrow cells as cytostatic effectors responsible for suppressing leukemia growth in vitro.

When bone marrow (BM) cells, isolated from normal (C57BL/6 x DBA/2)F1 mice (H-2b/H-2d), were cultured with leukemic cells for 24 hours, a significant tumor growth suppression, without noticeable tumor cell killing, was found. The level of BM cell-mediated cytostasis of both P815 mastocytoma (H-2d) and L1210 lymphoma (H-2d) cells was dependent on BM-to-tumor cell ratio; 100% growth inhibition was obtained at a ratio of 480/1. In addition, BM cells were found to be able to synergize in suppressing P815 cell growth with lymphoid cells. The synergistic suppressive effects on tumor cell proliferation were observed in BM-spleen, BM-thymus and BM-lymphnode cell co-cultures. The analysis of cytostatic activity of the cell culture supernatants showed that the synergistic leukemia growth suppression could be mediated, at least in part, by cell-derived soluble cytostatic molecules. The data presented herein also indicated that culturing BM cells with either crude supernatant (25%) from allogeneic mixed lymphocyte culture (MLC) or recombinant human interleukin(IL)-2 (20 U/ml) for 20 hours led to a 2-fold increase in their cytostatic activity against both P815 and L1210 cells. Taken together, the results suggest that although normal BM cells are ineffective in tumor cell killing, they may play an important role in cell-mediated effector mechanisms responsible for suppressing leukemia development; and that activated T lymphocytes, through producing cytokine(s), may rapidly upregulate leukemia growth inhibitory activity of BM cells.

A possible role of soluble receptors to cell growth factors in body aging.

It is assumed that production by differentiated cells of soluble receptors to cell growth factors may mediate a feedback mechanism controlling cell growth and differentiation in the body. Based on this assumption, it is hypothesized that with age a concentration of such soluble receptors in the body fluids gradually augments as a consequence of increasing a proportion of the differentiated cell pool. In the old body, when present in the cellular microenvironment at relatively high concentrations these receptors might markedly diminish ligand binding to the membrane-bound counterparts in a competitive manner and, thereby, significantly reduce cell regeneration activity. Under such conditions, the niches forming because of cell death could be being filled by connective fibers rather than newly generated cells.

A pendular mechanism for maintenance of the immune memory.

A possible mechanism for maintaining immune memory, based on idiotypic-anti-idiotypic interactions, is described. It is proposed that pendular dynamic swings in the levels of idiotypic antibodies (Ab1) and anti-idiotypic Ab2 may underlay immune memory. In the terms of the advanced concept, Ab dynamics in the maternal body might also play a significant role in education of the neonatal immune system.

A balance between tissue-destructive and tissue-protective immunities: a role of toll-like receptors in regulation of adaptive immunity.

The immune system has been shown to be involved in not only the host defense against infectious pathogens but also in tissue repair processes continuously occurring in the body. Our review presents the hypothesis about the mechanism of TLR-mediated regulation of adaptive immune responses linked to the tissue destruction. In our opinion following injury to a tissue, the expression of tissue-specific determinant/MHC class II complexes on dendritic cells and macrophages are upregulated significantly due to the increased uptake of tissue debris. Consequently, T-cells become activated as a result of low affinity, but high avidity interactions between self-reactive CD4+T cells and antigen-presenting cells (APCs). The type of self antigen-induced immune responses depends on the multiple downstream signals generated by intracellular toll-like receptors (TLRs) 3, 7, 8, and 9, that discriminate "self" and "non-self" nucleic acids. Accumulating data suggest that ligation of intracellular TLRs by endogenous DNA/RNA released from necrotic cells may result in developing Th2-like responses, as well as in the alternative activation of macrophages (M2), that favor local tissue protection and compensatory cell growth. In contrast, ligation of intracellular TLRs by exogenous pathogen-derived DNA/RNA may promote Th1-driven responses, as well as classical activation of macrophages (M1), that contribute to local tissue destruction and suppress cell growth. We suggest here that the balance between the host- and pathogen-derived nucleic acids interacting with intracellular TLRs contributes to the balance between immune-mediated tissue-protective and tissue-destructive events occurring in the body.