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1.
FEMS Immunol Med Microbiol ; 27(3): 235-40, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10683468

ABSTRACT

In this study, we examined the invasive capacity of Staphylococcus aureus and Salmonella typhi in human keratinocytes and monitored the number of viable intracellular bacteria at different post-infection times. The strains tested entered keratinocytes; both S. typhi and S. aureus were internalized within 30 min to 2 h after infection. No intracellular multiplication was observed, but S. typhi and S. aureus remained viable 72 h after infection. We also demonstrated that keratinocyte death following S. typhi and S. aureus invasion occurs by apoptosis as shown by DNA fragmentation. After 24 h of infection with S. typhi, the number of cells undergoing apoptosis were higher compared to infection with S. aureus. For prolonged infection times (48 h, 72 h) with both bacteria, there was no significant change in the number of cells undergoing apoptosis. The results demonstrated that viable intracellular S. typhi and S. aureus induced apoptosis in keratinocyte cells.


Subject(s)
Apoptosis , Keratinocytes/microbiology , Salmonella typhi/pathogenicity , Staphylococcus aureus/pathogenicity , Cells, Cultured , DNA Fragmentation , Humans , Keratinocytes/cytology , Salmonella typhi/growth & development , Staphylococcal Infections/microbiology , Staphylococcus aureus/growth & development , Typhoid Fever/microbiology
2.
FEMS Immunol Med Microbiol ; 16(3-4): 309-15, 1996 Dec 31.
Article in English | MEDLINE | ID: mdl-9116650

ABSTRACT

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).


Subject(s)
Cell Adhesion Molecules/biosynthesis , Cell Wall/immunology , Leukocytes, Mononuclear/immunology , Staphylococcus aureus/immunology , Acetylmuramyl-Alanyl-Isoglutamine/immunology , Acetylmuramyl-Alanyl-Isoglutamine/pharmacology , Animals , CD18 Antigens/biosynthesis , Cell Aggregation , Cell Membrane/physiology , Cell Wall/chemistry , Leukocytes, Mononuclear/cytology , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Lymphocyte Activation , Lymphocyte Function-Associated Antigen-1/biosynthesis , Lymphocytes/cytology , Lymphocytes/immunology , Macrophage-1 Antigen/biosynthesis , Membrane Fluidity , Mice , Monocytes/cytology , Monocytes/immunology , Muramic Acids/immunology , Muramic Acids/pharmacology , Spleen/cytology , Spleen/immunology , Staphylococcal Protein A/immunology , Staphylococcal Protein A/pharmacology , Teichoic Acids/immunology , Teichoic Acids/pharmacology
3.
Res Microbiol ; 146(6): 507-15, 1995.
Article in English | MEDLINE | ID: mdl-8525067

ABSTRACT

The continuous stimulation of the immune system using cell wall antigens from Brucella melitensis was found to cause both quantitative and qualitative changes in circulating lymphocyte populations in mice. Animals were inoculated in the hind legs with antigens on alternate days for varying lengths of time. During a two-month period, we saw a higher number of circulating lymphocytes, with an increase in the number of CD4+ cells (L3T4+) and B lymphocytes (I-Ad). After two months, a drop in the overall number of circulating lymphocytes occurred, with a decrease in CD4+ cells and an increase in CD8+ cells. During the first two months, we observed a size increase in popliteal lymph nodes and an elevated humoral response. The response then waned with the declining CD4+ cells. In the first two months, the treated animals also showed an in vitro response to two mitogens, concanavalin A and lipopolysaccharide and to the cell wall fraction, after which the treated animals showed a decreased response.


Subject(s)
Antigens, Bacterial/immunology , B-Lymphocytes/immunology , Brucella melitensis/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Animals , Antibody Formation , Fluorescent Antibody Technique , Hypertrophy/pathology , Lymph Nodes/immunology , Lymph Nodes/pathology , Lymphocyte Count , Male , Mice , Mice, Inbred BALB C
4.
FEMS Immunol Med Microbiol ; 10(3-4): 235-43, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7773240

ABSTRACT

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.


Subject(s)
Adjuvants, Immunologic , Antigens, Bacterial/immunology , Brucella melitensis/immunology , Immunity, Cellular , Liposomes/immunology , Lymphocyte Activation , Animals , Antibody Formation , B-Lymphocytes/immunology , Mice , Spleen/cytology , T-Lymphocytes, Cytotoxic/immunology , T-Lymphocytes, Helper-Inducer/immunology
5.
Life Sci ; 55(7): 499-509, 1994.
Article in English | MEDLINE | ID: mdl-8041229

ABSTRACT

Liposomes consisting of dicetyl-phosphate, cholesterol, lecithin and stearic or myristic or oleic acid, exert a protective effect for mice against experimental infection by Salmonella typhimurium, and delay both the onset and mortality B16 melanoma in these animals. Liposomes labelled with 3H-myristic acid were used as probes in the spleen and liver. We found that the treatment schedule rather than route of administration of liposomes, is important. The results show that in order to induce protection, preventive treatment must start at least three days before. Longer treatments do not increase the degree of protection, and treatments started at the same time as, or following experimental infection or tumor transplantation, have no effect.


Subject(s)
Liposomes , Melanoma, Experimental/prevention & control , Myristic Acids/therapeutic use , Oleic Acids/therapeutic use , Salmonella Infections/therapy , Stearic Acids/therapeutic use , Animals , Bacteremia/microbiology , Bacteremia/therapy , Disease Models, Animal , Female , Infections , Liposomes/pharmacokinetics , Liver/ultrastructure , Mice , Mice, Inbred BALB C , Myristic Acid , Oleic Acid , Salmonella Infections/microbiology , Salmonella typhimurium , Spleen/ultrastructure
6.
Life Sci ; 53(12): 981-9, 1993.
Article in English | MEDLINE | ID: mdl-8361329

ABSTRACT

The immunoregulatory role of prolactin (PRL) has been well established. In order to clarify if the hormone is also able to stimulate a protective activity against pathogens-induced infections we have studied the modifications of the infective capacity of Salmonella typhimurium induced in mice by repeated treatments with ovine PRL. A significant dose-dependent reduction in the mortality rate was observed in comparison to controls. This activity is probably related to the observed increases in phagocytosis and intracellular killing of the peritoneal macrophages and chemotaxis of the peritoneal granulocytes induced by the hormonal treatment. On the contrary, the number of leukocytes in blood was not modified by PRL treatment excluding a mobilization of cells from other districts. Our findings confirm the existence of a linkage between the neuroendocrine and immune systems suggesting a possible role for PRL in the regulation of non-specific immune response.


Subject(s)
Prolactin/therapeutic use , Salmonella Infections, Animal/prevention & control , Salmonella typhimurium , Animals , Chemotactic Factors/pharmacology , Chemotaxis, Leukocyte/drug effects , Dose-Response Relationship, Drug , Leukocytes/drug effects , Leukocytes/physiology , Macrophages/drug effects , Macrophages/physiology , Male , Mice , Neutrophils/drug effects , Neutrophils/physiology , Phagocytosis/drug effects , Salmonella Infections, Animal/blood , Sheep
7.
Immunopharmacol Immunotoxicol ; 13(4): 623-42, 1991.
Article in English | MEDLINE | ID: mdl-1774438

ABSTRACT

Our study considered the possibility of modifying the functional response of human neutrophils, of mouse lymphocytes and macrophages treated with phospholipids having different polar groups, different isomerisms with saturated and unsaturated fatty acids from C12 to C20 carbon atoms. The results are as follows. a) Most of the phospholipids containing fatty acids from C12 to C20 cause inhibition of the blastogenic capacity of the polyclonal activators tested. b) The phospholipids tested cause a decrease in adherence of polymorphonuclear leukocytes with the exception of the phosphatidyl-choline containing saturated and unsaturated fatty acids. c) A decrease in polymorphonuclear leukocytes migrational capacity almost always occurs. d) The cells treated with L-phosphatidyl-ethanolamine having fatty acids from C14 to C17 show an increase in chemiluminescence; those treated with phosphatidyl-choline and L-phosphatidyl-glycerol show a decrease of the chemiluminescence; L-phosphatidic acid and L-phosphatidyl-ethanolamine having Microbial fatty acids (FAs) at C16 cause a decrease in the formation of phagolisosomes in the macrophages tested.


Subject(s)
Lymphocytes/drug effects , Macrophages/drug effects , Membrane Lipids/pharmacology , Neutrophils/drug effects , Phospholipids/pharmacology , Animals , Cell Adhesion/drug effects , Chemotaxis, Leukocyte/drug effects , Humans , In Vitro Techniques , Luminescent Measurements , Lymphocyte Activation/drug effects , Membrane Fluidity , Membrane Lipids/chemistry , Mice , Phagocytosis/drug effects , Phospholipids/chemistry
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