F. Galdiero

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.

Effect of Salmonella typhimurium porins on biological activities of human polymorphonuclear leukocytes

The effect of Salmonella typhimurium porins on human polymorphonuclear leukocytes (PMNs) was studied. Labeled porins were shown to bind to the PMNs, and could be completely displaced by unlabeled porins. The binding caused modifications of membrane integrity and of the physico-chemical characteristics of the PMN surface, e.g. decreased oxidative burst, decreased hydrophobicity and altered cell morphology. The porins acted as both chemotaxins and chemotaxinogens. When PMNs were preincubated with porins their migration in the presence of commonly used chemoattractants (serum activated by zymosan or N-formyl-L-methionyl-L-leucyl-L-phenylalanine) was inhibited.

Inhibition of macrophage phagocytic activity by SV-IV, a major protein secreted from the rat seminal vesicle epithelium.

The protein SV-IV, one of the major secretory proteins produced by the rat seminal vesicle epithelium, has been found to possess a marked ability to inhibit in vitro the phagocytic properties of activated peritoneal rat macrophages, by a mechanism that apparently involves phagocytes and target cells. Although SV-IV is a substrate for transglutaminase (TGase), an enzyme secreted by activated macrophages, TGase does not seem to play any significant role either in the binding of the protein to the cells participating in the phagocytic process or in the inhibition of macrophage phagocytosis by SV-IV. The significance of the findings in relation to the reproductive process and their possible clinical implications are discussed.

Inhibitory effect of SV-IV, a major protein secreted from the rat seminal vesicle epithelium, on phagocytosis and chemotaxis of human polymorphonuclear leukocytes

The effect of SV‐IV, one of the major proteins secreted from the rat seminal vesicle epithelium, on phagocytosis and chemotaxis of human polymorphonuclear leukocytes (PMNs) has been studied. Various cytological, biochemical, metabolic, and physical correlates of both biological activities have been found to be markedly reduced by the presence in the medium of micromolar concentrations of protein SV‐IV. Moreover, the Scatchard analysis of the labeled SV‐IV binding to PMN cell surface has demonstrated that such binding is specific. The binding sites contain only saturable components, completely displaceable by unlabeled SV‐IV. The number of the specific sites has been calculated to be 87,000/cell, with a Kd of 1.72 x 10‐7 M. The molecular mechanism of the inhibitory effect is discussed along with the possible biological and clinical implications of the experimental findings.

Beneficial effects of myristic, stearic or oleic acid as part of liposomes on experimental infection and antitumor effect in a murine model

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.

Correlation Between Modification of Membrane Phospholipids and Some Biological Activity of Lymphocytes, Neutrophils and Macrophages

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.

Some biological activities of Eikenella corrodens major outer membrane proteins

AbstractMajor outer membrane proteins of Eikenella corrodens, an organism frequently isolated from patients with periodontal disease, were tested for some biological activities. Mouse peritoneal macrophages, exposed at low concentrations of the above-mentioned proteins (between 0.05 and 5 μg/ml), showed evident and marked morphological modifications consisting of increases in the size and vacuolation of the cells. Higher concentrations showed a toxic effect. Low concentrations resulted in a selective release of lysosomial enzymes without any significant release of lactatedehydrogenase, and cytoplasmic marker; while concentrations of 25–50 μg/ml, which were toxic in trypan-blue exclusion test, increased LDH release. Eikenella corrodens major proteins increased the platelet aggregation of ADP and thrombin.The residual complement activity of serum samples incubated with various amounts of proteins at 37°C for 30 minutes appeared strongly reduced with respect to controls, thus showing a consumption of the complement components.These results suggested that Eikenella corrodens major proteins may play a role in the development of periodontal lesions.

Phagocytosis of bacterial aggregates by granulocytes

A study was conducted on the granulocytic phagocytosis of bacterial aggregates obtained under ideal environmental conditions. For the strains studied, aggregation was favored by low salt concentrations, low pH and temperatures between 30°C and 40°C. Our results show that the phagocytic capacity of granulocytes depends on the type and size of these aggregates. Those formed by a smaller number of cells are more easily phagocytized than the larger ones.

Further characterization of the impaired protective function in mice fed with lipid diet

Female mice were maintained on lipid diet for 20 days. The nonspecific and immunological defense capability was determined by in vitro and in vivo methods. It was found that mice held mostly on a lipid diet demonstrate an all-round lowered response. Following 20 days of lipid diet the splenocytes exhibit: (1) an inversed lipid-protein ratio; (2) an inability to respond to sheep erythrocytes; (3) a reduction in [3H] thymidine incorporation in splenocytes stimulated with lipopolysaccharide (LPS) or with concanavalin A; (4) a reduction in the number of cells bearing surface immunoglobulins in splenocytes stimulated with LPS; (5) an inhibition of phagocytosis and intracellular killing in macrophages; (6) a lowering in granulocyte chemotaxis and adherence capacity; (7) a higher mortality to LPS after loading with galactosamine; and (8) a lowered complement activity even following LPS activation.

Phagocytosis and resistance to Salmonella typhimurium infection in mice fed with lipidic diet

The peritoneal macrophages from mice on a lipidic diet have shown an increase of surface hydrophobicity of cytoplasmatic membrane. This fact is correlated with a decrease of the phagocytic index and with an impairment of Salmonella typhimurium.[/p]