Biomedical subjects

M Galdiero

Publications and source records attributed to M Galdiero.

At least 37 records · Page 2Linked to original sources

PubMed1998

Th1 and Th2 cell involvement in immune response to Salmonella typhimurium porins.

In understanding the regulation of the specific immune response to Salmonella typhimurium, the role of a surface major component (porins) was studied. In this study we demonstrate that purified porins are able to induce a different response to that induced by the porins present on the S. typhimurium cell surface. Porin-treated or orally infected mice show anti-porin antibodies with bactericidal activity. The complete adoptive transfer of resistance to S. typhimurium is achieved only using splenic T cells from survivor mice after experimental infection. After stimulation with specific antigen in vitro CD4+ cells from porin-immunized mice released large amounts of interleukin-4 (IL-4), at a time when CD4+ cells from S. typhimurium-infected mice predominantly secreted interferon-gamma (IFN-gamma). Limiting dilution analysis showed that infection resulted in a higher precursor frequency of IFN-gamma-producing CD4+ T cells and a lower precursor frequency of IL-4-producing CD4+ T cells, while immunization with porins resulted in a higher precursor frequency of IL-4-producing cells and a low frequency of IFN-gamma-producing cells. Analysis of polymerase chain reaction-amplified cDNA from the spleens of infected mice revealed that IFN-gamma, IL-2 and IL-12 p40 mRNA were found 5 days after in vitro challenge and increased after 15 days; IL-10 expression was barely present after both 5 and 15 days, while IL-4 mRNA expression was not detected. In immunized mice, the IL-4 mRNA expression increased after 15 days, IFN-gamma mRNA expression disappeared entirely after 15 days, while IL-2, IL-10 and IL-12 mRNA remained relatively unchanged.

Adoptive Transfer↗

PubMed1998

Effect of Pasteurella haemolytica outer membrane proteins on bovine neutrophils.

The major outer membrane proteins (OMPs) isolated from Pasteurella haemolytica induce alterations of the biological activity of bovine polymorphonuclear leukocytes (PMNs). A dose-dependent reduction of the capacity of adherence to nylon wool in vitro was observed. OMPs also acted as chemotaxins at concentrations between 5 and 20 microg/ml. Concentrations lower than 5 microg/ml did not give considerable results. Preincubation with 5 microg/ml of OMPs led to modifications in the values of the phagocytic index and of intracellular killing, which were found to be diminished with respect to controls.

Animals↗

PubMed1998

Effects of the major Pasteurella multocida porin on bovine neutrophils.

OBJECTIVE: To evaluate in vitro effect of the major fraction of outer membrane proteins of Pasteurella multocida with porin-like activities on some biological functions of bovine neutrophils. ANIMALS: Neutrophils from 5 adult cattle. PROCEDURE: Variations in such biological processes as actin polymerization and chemotaxis and evaluation of hydrogen peroxide attributable to variable concentrations of P multocida were recorded and compared. Data were obtained, using the porin and lipopolysaccharide (LPS) isolated from a strain of P multocida cultivated in brain-heart infusion (BHI) broth. Various concentrations of porin and LPS were analyzed to evaluate changes in functional activation and microbicidal activity of bovine neutrophils. RESULTS: The 37.5-kd major polypeptide of the outer membrane of P multocida was isolated. Presence of this porin was significantly correlated with variations of some biological functions of bovine neutrophils. These immunocompetent cells had a concentration-dependent increase in actin polymerization and chemotactic activity. A concentration-dependent variation in the oxidative burst also was observed. CONCLUSIONS: The porins of gram-negative bacteria affect several biological functions of cells involved in the immune response as well as in inflammation. Significant correlation of results of in vitro experiments also was identified between porin and LPS effect. Pretreatment of bovine neutrophils with various concentrations of porin always caused a concentration-dependent increase in examined biological activities.

Actins↗

PubMed1997

Polyclonal T cell elimination by prolonged immunostimulation in an experimental model.

An experimental model of immunological deficiency obtained by treating mice for 6 months with serum of human blood drawn from different healthy individuals has been studied. The results show that an alteration of a circulating lymphocyte population with alterations of the ratio CD4+/CD8+ appeared in mice stimulated for a long period with immunogens. Mice treated for 2-4 months showed an increase in B lymphocytes and a decrease in the total number of T lymphocytes, with a decrease in CD4+ lymphocytes and an increase in CD8+ lymphocytes. After 4 months, the CD8+ lymphocyte population started to decrease, with a ratio of CD4+/CD8+ reaching almost 1. In animals treated for 2-3 months, the mean survival time (MST) following experimental infection with Salmonella typhimurium presented a decrease to 5 days, and after 5-6 months of treatment presented a decrease to 3-2.5 days. The bacteraemia was modified in comparison with controls. Prolonged exposure to antigens also induced lymphocyte apoptosis: cells of animals treated for 4-6 months presented increased levels of apoptosis with a percentage that reached 30-35%. A semiquantitative evaluation of the level of heat shock protein (hsp) in splenic lymphocytes showed an increase in the presence of hsp60 and hsp70 in the first 3 months of treatment, which then remained constant for up to 6 months.

Animals↗

PubMed1997

Cytokine and adhesion molecule expression in human monocytes and endothelial cells stimulated with bacterial heat shock proteins.

Bacterial heat shock proteins (HSPs) from Escherichia coli (GroES, GroEL, and DNAk) were tested for their ability to induce by themselves the expression and release of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and granulocyte-monocyte colony-stimulating factor (GM-CSF) by human monocytes and GM-CSF, IL-6, E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) by human umbilical vein endothelial cells (HUVEC). Our study demonstrated that treatment of monocytes with DNAk increased IL-6, TNF-alpha, and GM-CSF release in a dose-dependent manner. The same effect was elicited by GroEL but at a lower rate. Treatment of HUVEC cultures with DNAk and GroEL also increased GM-CSF, IL-6, E-selectin, ICAM-1, and VCAM-1 release in a dose-dependent fashion. In any case, the greatest release was obtained by using DNAk and GroEL at a concentration of 1 microg/ml. DNAk and GroEL were also able to up-regulate the surface expression of E-selectin, ICAM-1, and VCAM-1. As detected by reverse transcription-PCR analysis, DNAk and GroEL also increased the steady-state levels of cytokines and adhesion molecules in human monocytes and endothelial cells. In our study GroES showed a significant activity only on the release, surface expression, and mRNA transcription of E-selectin. Adhesion molecule expression seems to be a direct effect of HSPs and not via cytokines. Furthermore, these effects are due to HSPs properties because they are inhibited by specific monoclonal antibodies. These findings support the potential role of HSPs in modulating cell interactions during immunological and inflammatory responses.

Cell Adhesion Molecules↗

PubMed1997

Site-directed and linker insertion mutagenesis of herpes simplex virus type 1 glycoprotein H.

The gH-gL complex of herpes simplex virus type 1 (HSV-1) is essential for virion infectivity and virus-induced cell fusion, but functional domains of the gH molecule remain to be defined. We have addressed this question by mutagenesis. A set of linker insertion mutants in HSV-1 gH was generated and tested in transient assays for their ability to complement a gH-negative virus. Insertions at three sites in the C-terminal third of the external domain affected the ability of gH to function in cell-cell fusion and virus entry, while insertions at six sites in the N-terminal half of the external domain induced conformational changes in gH such that it was not recognized by monoclonal antibody LP11, although expression at the cell surface was unchanged. A recombinant virus in which a potential integrin-binding motif, RGD, in gH was changed to the triplet RGE entered cells as efficiently as the wild type, indicating that HSV-1 entry is not mediated by means of the gH-RGD motif binding to cell surface integrins. Furthermore, mutagenesis of the glycosylation site which is positionally conserved in all herpesvirus gH sequences in close proximity to the transmembrane domain generated a recombinant virus that grew in vitro with wild-type single-step kinetics.

Animals↗

PubMed1997

Growth hormone release of interleukin-1 alpha, interferon-gamma and interleukin-4 from murine splenocytes stimulated with staphylococcal protein A, toxic shock syndrome toxin-1 and streptococcal lysin S.

We investigated changes in the IL-1 alpha, IFN-gamma and IL-4 release from splenocytes in the presence of growth hormone (GH). Splenocytes were stimulated with Protein A (PA), Toxic Shock Syndrome Toxin-1 (TSST-1) and Streptolysin S (SLS). In the presence of GH, splenocytes stimulated with PA, induced a 40% and 50% drop in IL-1 alpha and IFN-gamma release respectively, compared to controls, while no changes were shown in IL-4 release. The release of IFN-gamma by TSST-1-stimulated splenocytes fell by 30%, while no changes were shown in IL-1 alpha and IL-4 release after GH. The release of IL-1 alpha by SLS-stimulated splenocytes increased by 50% in the presence of GH. No changes were shown in IFN-gamma and IL-4 release. The results are discussed in terms of the possibility of an expanding function for these endocrine peptides within the immune system.

Animals↗

PubMed1996

CD11a/CD18 and CD11b/18 modulation by lipoteichoic acid, N-acetyl-muramyl-alpha-alanyl-D-isoglutamine, muramic acid and protein A from Staphylococcus aureus.

This study investigates the effect of some components of the Staphylococcus aureus cell wall [lipoteichoic acid (LTA), N-acetyl-muramyl-alanyl-D-isoglutamine (MD), muramic acid (MA) and protein A (PA)] in modulating expression of cell-surface adhesion molecules CD11a/CD18, CD11b/C18 on monocytes qualitatively and quantitatively. Monocytes incubated with bacterial components presented different CD11b/CD18 expressions which were dose-dependent in contrast to controls. The results obtained demonstrated that lymphocytes incubated with bacterial components also increased the expression of CD11a/CD18. The modifications in activation of CD11a/CD18 and CD11b/CD18 expression are probably correlated with modifications of membrane fluidity measured as polarisation fluorescence (P).

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1996

Recombinant human prolactin induces protection against Salmonella typhimurium infection in the mouse: role of nitric oxide.

In the present study, we demonstrated that repeated treatment with recombinant human prolactin (rhPRL) protected mice against Salmonella typhimurium infection. The protective activity was statistically significant, dose-dependent and present only when rhPRL treatments were performed before the infection. This activity was probably related to the observed increases in phagocytosis and intracellular killing of peritoneal macrophages induced by the hormonal treatment. The number of peripheral leukocytes was not modified, excluding a mobilization of cells from other compartments. A decrease in the mortality rate after challenge was also observed in mice treated with the monoclonal antibody anti-PRL receptor U5, confirming that the protective activity was associated with receptor activation. Our studies also suggest that nitric oxide (NO) production was involved in the protective effect of rhPRL since pre-treatment of the animals with L-NAME, an inhibitor of NO-synthase, was able to completely revert the protective activity, whereas D-NAME, the inactive D-isomer, was without effect.

Animals↗

PubMed1996

Growth hormone modulates IL-alpha and IFN-gamma release by murine splenocytes activated by LPS or porins of Salmonella typhimurium.

The effect of growth hormone (GH) on the release of IL-1alpha and IFN-gamma from murine splenocytes was investigated. Their release from splenocytes activated by Salmonella enterica serovar Typhimurium lipopolysaccharide (LPS) 0.5 microg/ml was increased by c. 65% in the presence of GH 100 pg/ml. With splenocytes activated by S. Typhimurium porins 5 microg/ml, GH increased the production of both IL-1alpha and IFN-gamma by c. 56%. Polymyxin treatment abolished the cytokine-releasing activity of LPS but had no effect on the activity of the porin preparation.

Animals↗

PubMed1996

Susceptibility to toxoplasmosis: correlation between macrophage function, brain cyst formation and mortality in rats.

Rats are resistant to Toxoplasma infection, and in contrast to mice do not form cysts in their tissues. Because rats treated with beta adrenergics, corticosteroids or 60cobalt are more susceptible to toxoplasmosis, we conducted experiments to investigate if the impaired resistance of drug-treated rats is related to macrophage function or induction of cystogenic capacity. Our experiments in 0.7 or 1.2 mg/kg-corticosteroid or 12 Gy-60cobalt-treated rats indicated that the decreased survival rate (P < 0.001 to P < 0.0001, compared to infected-untreated or infected-unirradiated animals) was associated with a decrease of both macrophage toxoplasmastatic activity and intracellular killing (P < 0.05 each group), compared to infected-untreated or infected-unirradiated rats. However in 9 Gy-60cobalt-treated animals the decreased survival rate (P < 0.001, compared with control rats) was accompanied only by a decrease of the toxoplasmastatic activity in comparison to macrophages of the control animals. Moreover in these animals, the release of NO2- by these macrophages was poorly detectable (P < 0.05) or completely inhibited (P < 0.01) in comparison with infected-untreated or infected-unirradiated rats. In contrast, in all groups of rats treated with high doses of beta adrenergic, the decreased survival (P < 0.001 to P < 0.0001, compared with untreated rats) was accompanied by values of intracellular killing and intracellular proliferation of Toxoplasma parasites that did not significantly (P = ns each group) differ from macrophages of infected-untreated rats. Furthermore in the high beta adrenergic treated groups only small amounts of NO2- were detectable (P < 0.05) in comparison with control animals. In addition, our data in rats treated with 0.7 or 1.2 mg/kg of corticosteroid or 12 Gy of 60cobalt indicated that the increased mortality was correlated to the presence of a small number of cysts in their brains (P < 0.05; P = ns; P < 0.01 respectively) in comparison to infected-untreated or infected-unirradiated rats. These results suggest that the susceptibility of drug-immunosuppressed rats is not due exclusively to a deficient macrophage function, but is probably also linked to immune mechanisms involved in the process of cystogenesis.

Adrenergic beta-Antagonists↗

PubMed1996

Prolactin regulates IL-1 alpha, IFN-gamma and IL-4 release from mouse splenocytes stimulated with some staphylococcal and streptococcal toxins.

This study investigates changes in IL-1 alpha, IFN-gamma and IL-4 from mouse splenocytes stimulated with Staphylococcal Protein A (PA), or Toxic Shock Syndrome Toxin-1 (TSST-1), or Streptococcal lysin S (SLS) after exposure to Prolactin (PRL). In the presence of PRL, IL-1 alpha and IFN-gamma induction by PA-stimulated splenocytes was reduced by 74% and 25% respectively. On the other hand, IL-4 release was enormously increased. The ability of TSST-1 to induce IFN-gamma release was decreased by 32% after PRL. IL-1 alpha and IL-4 was unchanged compared to controls. In the presence of PRL, IFN-gamma release from splenocytes stimulated with SLS, was increased by 60%, while no changes were shown in IL-1 alpha and IL-4 release.

Animals↗

PubMed1995

Effects of benzodiazepines on immunodeficiency and resistance in mice.

Our results indicate that benzodiazepine (Bz) treatment time, greater than 2-3 months, induce a decrease of both specific and nonspecific responses. Mice treated for different times with diazepam or chlordemethyldiazepam showed decreased survival to experimental Salmonella typhimurium infections after three months of treatment. Adherence, expressed as the polymorphonuclear cells (PMN) capacity to attach to nylon wool, was impaired after 7 days of treatment. Longer treatments further increase this impairment. PMN from mice treated with Bz for 90 days also demonstrate on impaired chemotaxis and phagocytosis for Saccharomyces cerevisiae. Monocytes from mice treated for 7 days secreted more IL-1 alpha then controls; the antibody titer in mice given to prolonged treatment progressively diminished compared to controls. Con A or LPS stimulated lymphocytes showed an increase of H3-thymidine incorporation from mice treated for a short time and conversely a decreased incorporation when taken from mice that underwent longer treatments. Benzodiazepines were therefore found to affect PMN chemotaxis and phagocitosis, general immunity and survival of mice to infections.

Animals↗

PubMed1995

In vivo inhibition of cell-mediated and humoral immune responses to cellular antigens by SV-IV, a major protein secreted from the rat seminal vesicle epithelium.

Microgram amounts of protein SV-IV, a major secretory protein produced by adult rat seminal vesicle epithelium, markedly decrease the mouse humoral immune response to cellular xenogeneic or allogeneic antigens (sheep red blood cells (SRBC) or mouse epididymal spermatozoa). The significant reduction in the total number of splenocytes and their main cell subsets in SRBC-immunized mice, the dramatic decrease in the number of Ia+ splenic T cells and the marked inhibition of splenocyte ability to respond in vitro to polyclonal mitogen stimuli suggest that the macrophage accessory cells are the primary target of the SV-IV immunosuppressive activity in vivo. Moreover, the infection of SV-IV-treated mice with Salmonella typhimurium produced an increased mortality of the experimental animals associated with a marked decrease of the phagocytic and intracellular killing activities of their peritoneal macrophages.

Animals↗

PubMed1995

Prolactin and insulin regulate the release of IL-1-alpha and IFN-gamma from murine splenocytes activated with porins or LPS of Salmonella typhimurium.

Murine splenocytes treated with prolactin (PRL) or insulin were stimulated in vitro with porins or lipopolysaccharide (LPS) of Salmonella typhimurium. It was seen that PRL inhibits the release of IFN-gamma from splenocytes treated with porins by about 20% while having no effect on the release of IL-1-alpha. Splenocytes porin-stimulated splenocytes exhibited a remarkable increase in IL-1-alpha release (100%) and a diminished release of IFN-gamma (about 50%) in the presence of insulin. The splenocytes stimulated with LPS had a reduced release of IL-1-alpha (75%) and IFN-gamma (about 50%) when insulin was added. The data suggest that classical endocrine system participates in a bioregulatory feedback loop that may prevent unwanted toxicity from cytokine excess. However, some bacterial products sometimes enormously unbalance this regulatory network.

Adjuvants, Immunologic↗

PubMed1995

Enhanced cellular response in mice treated with a Brucella antigen-liposome mixture.

The capacity of liposomes constituted by dycetyl-phosphate (0.009 mM), cholesterol (0.017 mM), lecithin (0.003 mM), and myristic (0.1 mM), stearic (0.1 mM), or oleic acid (0.1 mM) to modify the lymphocyte response to Brucella melitensis antigens in mice was studied. Mice treated with antigens mixed with liposomes containing myristic, stearic or oleic acid had higher antibody titres than mice given antigen suspended in a saline solution. Liposomes alone, without Brucella antigens, resulted in increased 3H-thymidine incorporation by lymphocytes both in vivo and in vitro. The addition of polyclonal activators (LPS and ConA) caused a further increase of 3H-thymidine uptake. Moreover, spleen lymphocytes from mice inoculated with Brucella antigens mixed with the liposomes had a significantly lower population of B lymphocytes (10%), and a notable increase in the Tc lymphocytes (20%). Autoradiography of sections of popliteal ganglia of treated mice showed that the radioactivity was concentrated mainly in the membrane structures of the cell.

Adjuvants, Immunologic↗

PubMed1995

Modification of actin in peritoneal macrophages after diazepam treatment.

We have investigated the effect of therapeutic doses of diazepam (7 micrograms/mouse) on the association of actin with the macrophage cytoskeleton using cytochemical and morphological methods. Results obtained indicated that diazepam was able to modulate the content of actin in macrophages; such an effect proved to be time-dependent. After fixation and staining for indirect immunofluorescence with actin antibody, peritoneal macrophages from mice treated for short time with diazepam, showed a fluorescent intensity increase compared to control mice. The fluorescent intensity augmented reaching peak value within 14 days of treatment. Afterwards, this value dropped below control value for mice that underwent longer treatments. In the in vitro experiments concentrations of 10(-5) M, diazepam inhibited a well cell spread and a lower amount of actin after 15 min of incubation was also revealed. These results suggest that administration of diazepam in vivo plays a role in both the nonspecific and specific immune response, producing in the macrophages a reorganization process of microfilaments.

Actin Cytoskeleton↗

PubMed1995

Morphological changes induced in HEp-2 cells by Salmonella typhimurium porins.

The effects of different doses of Salmonella typhimurium porins were investigated on human laryngeal epithelial (HEp-2) cells by fluorescence and transmission electron microscopy. The changes observed in microfilament organization suggested an involvement of cytoskeleton in the cell response. Furthermore, morphologic phenomena characterized by ultrastructural membrane modifications also involved the nuclear membrane.

Cells, Cultured↗