Stimulation of natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities in murine leukocytes by bombesin-related peptides requires the presence of adherent cells

Effect of Amentoflavone on the Inhibition of Pulmonary Metastasis Induced by B16F-10 Melanoma Cells in C57BL/6 Mice

This study was an investigation of the antimetastatic activity of amentoflavone using B16F-10 melanoma—induced experimental lung metastasis in C57BL/6 mice. Amentoflavone treatment significantly reduced tumor nodule formation accompanied by reduced lung collagen hydroxyproline, hexosamine, and uronic acid levels. Serum sialic acid and γglutamyl transpeptidase levels were also significantly inhibited after amentoflavone treatment. Amentoflavone treatment up-regulated the lung tissue inhibitor of metalloprotease-1 and tissue inhibitor of metalloprotease-2 expression. The cytokine profile and growth factors such as interleukin-1β , interleukin-6, tumor necrosis factor-α, granulocyte monocyte— colony stimulating factor, vascular endothelial growth factor, interleukin-2, and tissue inhibitor of metalloprotease-1 in the serum of these animals were markedly altered after amentoflavone treatment. This altered level of cytokines after amentoflavone treatment was also accompanied by enhanced natural killer cell antibody—dependent cellular cytotoxicity. The study reveals that amentoflavone treatment could alter proinflammatory cytokine production and could inhibit the activation and nuclear translocation of p65, p50, c-Rel subunits of nuclear factor—κB, and other transcription factors such as c-fos, activated transcription factor—2, and cyclic adenosine monophosphate response element—binding protein in B16F-10 melanoma cells.

Nitric oxide released by accessory cells mediates the gastrin-releasing peptide effect on murine lymphocyte chemotaxis

Several neuropeptides, including gastrin-releasing peptide (GRP), modulate the immune response, specifically lymphocyte chemotaxis. In the present work the effect of GRP on the chemotaxis of murine lymphocytes from different immune locations in both, total leukocyte populations and populations depleted of adherent cells have been studied. Specificity of the GRP effect on chemotaxis using an antagonist of the GRP receptor, as well as the implication of nitric oxide (NO), using inhibitors of NO synthase and donors of NO, were investigated. The effects of GRP stimulating the chemotaxis of lymphocytes from peritoneum, axillary nodes and spleen and decreasing the chemotaxis from thymus were receptor-specific and disappeared in lymphocytes from populations depleted of adherent cells. NO synthase inhibitors blocked the GRP effect on lymphocyte chemotaxis, and this action was reversed in the presence of l-arginine. Thus, the effect of GRP on murine lymphocyte chemotaxis appears to be mediated by NO secreted by adherent cells.

Dipeptidyl peptidase IV activity and/or structure homologs: contributing factors in the pathogenesis of rheumatoid arthritis?

Several of the proinflammatory peptides involved in rheumatoid arthritis pathogenesis, including peptides induced downstream of tumor necrosis factor-α as well as the monocyte/T cell-attracting chemokines RANTES and stromal cell-derived factor (SDF)-1α and the neuropeptides vasoactive intestinal peptide (VIP) and substance P, have their biological half-lives controlled by dipeptidyl peptidase IV (DPPIV). Proteolysis by DPPIV regulates not only the half-life but also receptor preference and downstream signaling. In this article, we examine the role of DPPIV homologs, including CD26, the canonical DPPIV, and their substrates in the pathogenesis of rheumatoid arthritis. The differing specific activities of the DPPIV family members and their differential inhibitor response provide new insights into therapeutic design.

Neuropeptide Y effects on murine natural killer activity: changes with ageing and cAMP involvement

Changes in the bidirectional interaction between the nervous and the immune systems have been proposed as a cause of ageing. Neuropeptides, such as neuropeptide Y (NPY), could show different effects on immune function with age. In the present work, we have studied the in vitro action of a wide range of NPY concentrations, i.e. from 10(-13) to 10(-7) M, on natural killer (NK) activity, a function which decreases with age. Spleen, axillary nodes, thymus and peritoneum leukocytes from mice of different ages: young (12+/-2 weeks), adult (24+/-2 weeks), mature (50+/-2 weeks) and old (72+/-2 weeks) were used. Stimulation by NPY of NK activity was observed in adult and mature animals in axillary nodes and thymus, and an inhibition in the spleen from young mice. The specificity of the NPY effect on cytotoxic activity was confirmed using a C-terminal fragment of NPY. Furthermore, cAMP levels in leukocytes were found to be decreased by NPY in adult mice, suggesting an involvement of this messenger system in the NK modulation by this neuropeptide.

The NPY effects on murine leukocyte adherence and chemotaxis change with age. Adherent cell implication

The two-way communication between the nervous and immune system is currently well-known, but the age-related changes in this communication have been scarcely studied. In the present work, we have investigated the in vitro effects of neuropeptide Y (NPY) at concentrations ranging from 10(-13) to 10(-7) M on the adherence and chemotaxis capacities of spleen, axillary node, thymus and peritoneum leukocytes from BALB/c mice. The NPY effect on these functions was examined on cells from animals of four different ages, i.e. young (12+/-2 weeks old), adult (24+/-2 weeks old), mature (50+/-2 weeks old) and old (72+/-2 weeks old). In young animals, NPY stimulates the adherence of leukocytes from spleen, axillary nodes and thymus and inhibits it in cells from peritoneum. In adult animals NPY inhibits the adherence of leukocytes from thymus. These effects disappear with ageing in all locations. Chemotaxis is stimulated by this neuropeptide at all ages in cells from axillary nodes and peritoneum, but this effect is absent in old mice. NPY exerts an inhibitory effect on the chemotaxis of leukocytes from thymus at all ages studied. These NPY effects on leukocytes seem to be carried out through adherent cells.

Improvement of murine immune functions in vitro by thioproline

Previous studies have shown that several immune functions were improved in mice after the ingestion of a thioproline (thiazolidine-4-carboxylic acid) enriched diet. In the present work, we have studied the in vitro effects of several concentrations of this thiol compound (0.1, 0.5, 1, 2.5 and 5 mM) on the most relevant functions of three pivotal immune cells, namely, macrophages, lymphocytes, and natural killer (NK) cells from BALB/c mice. The results show that thioproline stimulates the phagocytic process of macrophages, increasing the mobility directed to the inflammatory focus (chemotaxis) and the phagocytosis of inert particles. It increases the adherence and the chemotaxis capacities of lymphocytes, their proliferative activity and favours the natural cytotoxic activity that could improve the capacity to destroy malignant cells. Thioproline concentrations of 0.5 and 1 mM were the most effective regarding the different functions analysed. These results suggest that the improvement of immune functions, observed in previous work, after thioproline-enriched diet ingestion is due to a direct action of this thiol compound on immune cells.

Effects in vitro of several antioxidants on the natural killer function of aging mice

The aim of the present work is to study the change with aging in the effect in vitro of several antioxidants: thiazolidine-4-carboxylic acid or thioproline, N-acetylcysteine (NAC), ascorbic acid (AA), and alpha-tocopherol (vitamin E, VE) on the natural killer (NK) activity in mononuclear cells from axillary nodes, spleen, thymus and peritoneal leukocytes from BALB/c male mice. Young (8+/-2 weeks), adult (24+/-2 weeks). mature (48+/-2 weeks), and old (72+/-2 weeks) animals were studied. A nonradioactive cytotoxic assay with cells from the murine lymphoma YAC-1 as target cells and a relation effector cells/target cells of 10/1 were used. The concentrations of the different antioxidants were: 1 mM for thioproline and N-acetylcysteine and 5 microM for ascorbic acid and alpha-tocopherol, which induced a maximum effect in our previous dose-response experiments. The results show that, in general, the above antioxidants cause an enhancement of the NK activity at all ages studied, this stimulation being higher with thioproline and N-acetylcysteine than with ascorbic acid and alpha-tocopherol. The effects were similar for the three lymphoid organs and the peritoneum. This stimulation of the NK activity by antioxidants is an important favorable response, especially in old mice, in which age results in a decrease in NK function and, therefore, in a higher incidence of neoplasia.

Changes with age in the modulation of natural killer activity of murine leukocytes by gastrin-releasing peptide, neuropeptide Y and sulfated cholecystokinin octapeptide

Several investigations have suggested that the interactions between the nervous and immune systems are modified with age. The aim of the present work was to study the effect of three neuropeptides: gastrin-releasing peptide (GRP), neuropeptide Y (NPY) and sulfated cholecystokinin octapeptide (CCK-8 s) on natural killer (NK) activity of spleen, thymus and axillary node leukocytes from BALB/c male, young (8+/-1 weeks), adult (24+/-2 weeks) and old (72+/-2 weeks) mice. We used cells from murine lymphoma YAC-1 as targets for the cytotoxic assay and three physiological concentrations of the neuropeptides (10(-8), 10(-10) and 10(-12) M). In control samples, in the absence of neuropeptide, we observed a decreased NK activity in young and old mice with respect to the adults in the three organs studied. Regarding the effect of the neuropeptides, GRP stimulates the cytotoxic activity of leukocytes from all locations, in adult animals. At the same age, NPY also stimulates the NK activity of leukocytes from axillary nodes and thymus, whereas it decreases the NK activity of spleen leukocytes from young mice. CCK-8 s has an inhibitory effect on the axillary node leukocytes from young mice and spleen leukocytes from old animals. However, CCK-8 s increased the NK activity of thymus leukocytes from young and adult mice. The results indicate that the highest values of NK activity are found in adult mice, and that the stimulating effect of the three neuropeptides studied on NK activity of leukocytes from adult mice are reduced or disappeared, in general, in old as well as in young animals. Furthermore, the changes observed with ageing in the modulation of NK activity by the neuropeptides studied suggest an altered integration of the nervous and immune systems.

Relation between exploratory activity and immune function in aged mice: a preliminary study

Previous studies show that fast exploration of a T-shaped maze by mature mice may predict an above average longevity. Since the nervous and the immune systems work in a coordinated fashion, and it seems that these two homeostatic systems both influence organismic aging and suffer a senescent decline, we have performed a comparative study of the above behavioral parameter and different functions of three representative immune cells: lymphocytes, macrophages and natural killer (NK) cells obtained from old (76 +/- 1 weeks of age) female OF1-Swiss mice. At 70 weeks of age the mice were divided into a 'fast' and a 'slow' group, containing 100 and 0%, respectively, of animals able to explore the 50 cm-long first arm of the maze in 20 s or less. At 76 +/- 1 weeks of age the animals were sacrificed, the peritoneal cell suspensions were obtained and the immune organs (axillary nodes, spleen and thymus) were isolated. The following leukocyte functions were studied in peritoneal macrophages: adherence to substrate, mobility (spontaneous and chemotaxis), ingestion of particles and superoxide anion production whereas mobility, lymphoproliferative response to the mitogen Con A and NK activity were studied in the immune-organ leukocyte suspensions. The results show that the aged fast mice have better immune functions than the aged slow mice.