Nicotinamide and 3-aminobenzamide interfere with receptor-mediated transmembrane signaling in murine cytotoxic T cells: independence of Golgi reorientation from calcium mobilization and inositol phosphate generation

The two competitive inhibitors of ADP-ribosylation, nicotinamide and 3-aminobenzamide, have been reported to interfere with TNF-induced cell apoptosis, and there is evidence that they inhibit killer-induced target cell lysis as well. There are very few drugs known to specifically interfere with target apoptosis induced by killer cells. We therefore sought to explore the effects these inhibitors have on CTL-mediated cell lysis. Here we show that TcR-mediated transmembrane signaling in CTL, measured by Ca2+ mobilization and generation of inositol phosphates, is inhibited by nicotinamide. The possibility that all cell functions are suppressed by the drug is excluded by the finding that constitutive secretion of BLT serine esterase is not inhibited, whereas stimulated secretion of this enzyme is suppressed. We also show that nicotinamide does not interfere with CTL target cell binding or reorientation of the Golgi apparatus toward the target binding site. It is concluded that nicotinamide inhibits transmembrane signaling in CTL and thereby interferes with delivery of the lethal hit to targets.

Effects of stress on lysability of tumor targets by cytotoxic T cells and tumor necrosis factor

The effects of stress on four tumor cell lines are analyzed in view of the possibility that stress protects tumor cells against immune attack. We show that stress causes resistance to CTL and TNF in two cell lines. Induction of resistance is time dependent and reversible and not due to failure of killer cells to interact with stressed targets. It is shown that stress induces stress proteins concomitant with induction of resistance to killer cells and TNF. Moreover experiments are presented suggesting that resistance to either immune effector is due to independent mechanisms. The conclusion that stress can induce mechanisms in targets that interfere with the action of TNF as well as with target lysis following a lethal hit by CTL is discussed.

Effects of stress on lysability of tumor targets by cytotoxic T cells and tumor necrosis factor

The effects of stress on four tumor cell lines are analyzed in view of the possibility that stress protects tumor cells against immune attack. We show that stress causes resistance to CTL and TNF in two cell lines. Induction of resistance is time dependent and reversible and not due to failure of killer cells to interact with stressed targets. It is shown that stress induces stress proteins concomitant with induction of resistance to killer cells and TNF. Moreover experiments are presented suggesting that resistance to either immune effector is due to independent mechanisms. The conclusion that stress can induce mechanisms in targets that interfere with the action of TNF as well as with target lysis following a lethal hit by CTL is discussed.

Differential effects of protein synthesis inhibition on CTL and targets in cell-mediated cytotoxicity

The reactions that lead to target cell lysis by cytotoxic T cells (CTL) are despite intensive investigations poorly understood. To examine the relative roles effectors and targets play in the lytic reaction, protein synthesis in either CTL or targets was inhibited before assay of lysis. We show, in agreement with previous results, that de novo protein synthesis is not necessary in either effectors or targets during the cytolytic reaction. However, activation of CTL requires protein synthesis. Activated CTL respond to protein synthesis inhibitors with a cycling of activity, a result that is interpreted to be consistent with a stimulus secretion mechanism. Treatment of targets with protein synthesis inhibitors prior to incubation with CTL leads to a very rapid and irreversible loss of lytic susceptibility. It is shown that the decrease in lysability is not due to lack of proper CTL target interaction: MHC class I antigens are expressed on drug-treated targets and these cells serve as cold targets in competitive inhibition experiments. Moreover, drug-treated targets trigger transient Ca2+ mobilization and generation of inositol phosphates in CTL. It is therefore concluded that drug-treated targets are able to trigger CTL function but lack a component that is required for their successful lysis.

Induction of tolerance to parental marrow grafts in F1 hybrid mice. Evidence for recognition of self-antigens

Lethally irradiated (C57BL/6xC3H)F1 mice are able to acutely reject parental C57BL/6 but not C3H marrow grafts, a phenomenon called hybrid resistance (HR). In attempts to inactivate this rejection mechanism we found that parental spleen cells activated with LPS are very potent in inducing tolerance to a subsequent C57BL/6 marrow graft. Tolerance is likely due to elimination of effector cells responsible for graft rejection as adoptive transfer of spleen cells from normal into tolerized mice reconstitutes responsiveness. Evidence is presented that the Ag on LPS-activated spleen cells responsible for induction of unresponsiveness are expressed on both C57BL/6 and (C57BL/6xC3H)F1 cells. This suggests that the HR effector cells recognize autoantigens. In support of this, induction of tolerance to C57BL/6 parental marrow grafts leads to a concomitant dramatic increase in endogenous CFU-spleen after a dose of gamma-irradiation. Moreover, elimination of the cells responsible for HR by injection of anti-ASGM1 antibody results in a similar increase of endogenous CFU-spleen after irradiation. It is concluded that HR is a reflection of autoimmunity, able to limit the proliferation of syngeneic marrow stem cells.

Induction of tolerance to parental marrow grafts in F1 hybrid mice. Evidence for recognition of self-antigens

Lethally irradiated (C57BL/6xC3H)F1 mice are able to acutely reject parental C57BL/6 but not C3H marrow grafts, a phenomenon called hybrid resistance (HR). In attempts to inactivate this rejection mechanism we found that parental spleen cells activated with LPS are very potent in inducing tolerance to a subsequent C57BL/6 marrow graft. Tolerance is likely due to elimination of effector cells responsible for graft rejection as adoptive transfer of spleen cells from normal into tolerized mice reconstitutes responsiveness. Evidence is presented that the Ag on LPS-activated spleen cells responsible for induction of unresponsiveness are expressed on both C57BL/6 and (C57BL/6xC3H)F1 cells. This suggests that the HR effector cells recognize autoantigens. In support of this, induction of tolerance to C57BL/6 parental marrow grafts leads to a concomitant dramatic increase in endogenous CFU-spleen after a dose of gamma-irradiation. Moreover, elimination of the cells responsible for HR by injection of anti-ASGM1 antibody results in a similar increase of endogenous CFU-spleen after irradiation. It is concluded that HR is a reflection of autoimmunity, able to limit the proliferation of syngeneic marrow stem cells.

Legionella gratiana sp. nov. isolated from French spa water

During an epidemiologic survey, an unidentified strain of Legionella was isolated from water of a thermal spa in France. The strain (Lyon 8420412) had the cultural and biochemical characteristics typical of the genus Legionella. In direct immunofluorescence tests, the strain reacted weakly with fluorescein-conjugated antisera prepared against L. bozemanii serogroups 1 and 2, L. longbeachae serogroups 1 and 2 and L. anisa, and failed to react with sera prepared against 36 other species or serogroups. A fluorescein-conjugated antiserum prepared against strain Lyon 8420412 reacted strongly with the homologous strain and only weakly with the above-mentioned species. The cell-wall fatty acid profile, with a predominance of hexadecenoic (16:1) and hexadecanoic (16:0) acids, ubiquinone Q10 as the major quinone and a characteristic protein electrophoresis profile suggested that the isolate was different from other Legionella species. In DNA-DNA hybridization experiments, the strain was distinct from all named Legionella species, and from all unnamed species currently under study at the Centers for Disease Control. The name Legionella gratiana is proposed for the new species (type strain Lyon 8420412; CDC 1242). A serologic survey of antibodies reacting against L. gratiana indicated that personnel or patients at the spa therapy centre where the organism was isolated had higher antibody titres than a control population.

A novel cell type responsible for marrow graft rejection in mice. T cells with NK phenotype cause acute rejection of marrow grafts

Acute rejection of allogeneic and semiallogeneic marrow grafts has long been considered to be a function of the natural immune system because it shares many features with NK activity in mice. With the use of a recently developed in vivo adoptive transfer assay in which spleen cells are transferred from mice able to reject a particular marrow graft into mice that fail to do so, we show that the cells responsible for induction of marrow graft rejection indeed display the phenotype of NK cells: they lack the T cell Ag CD4 and CD8 but express the NK Ag NK1 and ASGM1. The rejection induced by adoptively transferred cells is exquisitely specific--a feature that points to a specific recognition process by the transferred cells. To elucidate what the recognition structure on these cells may be we found that they express CD3 and most likely the beta-chain of the TCR. Highly purified responder cells with the NK1+, CD3+, CD4-, CD8- phenotype, when transferred into nonresponder recipients, cause specific marrow graft rejection. We conclude that the acute rejection of bone marrow grafts is caused by a cell that expresses NK phenotype but is of T cell lineage. This may suggest the specificity of acute marrow graft rejection is caused by a specific recognition process that involves TCR.

A novel cell type responsible for marrow graft rejection in mice. T cells with NK phenotype cause acute rejection of marrow grafts

Acute rejection of allogeneic and semiallogeneic marrow grafts has long been considered to be a function of the natural immune system because it shares many features with NK activity in mice. With the use of a recently developed in vivo adoptive transfer assay in which spleen cells are transferred from mice able to reject a particular marrow graft into mice that fail to do so, we show that the cells responsible for induction of marrow graft rejection indeed display the phenotype of NK cells: they lack the T cell Ag CD4 and CD8 but express the NK Ag NK1 and ASGM1. The rejection induced by adoptively transferred cells is exquisitely specific--a feature that points to a specific recognition process by the transferred cells. To elucidate what the recognition structure on these cells may be we found that they express CD3 and most likely the beta-chain of the TCR. Highly purified responder cells with the NK1+, CD3+, CD4-, CD8- phenotype, when transferred into nonresponder recipients, cause specific marrow graft rejection. We conclude that the acute rejection of bone marrow grafts is caused by a cell that expresses NK phenotype but is of T cell lineage. This may suggest the specificity of acute marrow graft rejection is caused by a specific recognition process that involves TCR.

Exposure to Legionellaceae at a hot spring spa: a prospective clinical and serological study

Following the occurrence of five cases of Legionnaires' disease among patients and therapists at a French hot spring spa, a series of cleansing procedures and an epidemiological study were undertaken. During a 3-month period, the spring water was repeatedly sampled. Serum samples were taken from 689 randomly selected patients, 230 therapists, 134 administrative staff and a control group of 904 blood donors. Legionellaceae were present in the spring water at concentrations of 10(3)-10(5) colony forming units/l. Fifteen different species or serogroups were isolated with Legionella pneumophila serogroups 3 and 1 predominating. No clinical cases of Legionnaires disease were observed during the study. However, 11% of the therapists and 5% of the patients either had a high titre of antibody (greater than or equal to 256) to at least one species or serogroup or seroconverted during the study. Mean antibody titres in the three study groups were significantly higher than those in the blood donors against 11 of the 32 legionella antigens tested. Nine of these 11 antigens corresponded to species or serogroups isolated from the spring water. The highest mean antibody titres in all three study groups were against L. pneumophila serogroup 3, the most common legionella in the spring water. These findings have important implications for the maintenance of adequate standards of hygiene, bacteriological sampling and clinical surveillance in this and similar establishments.

Comparative efficacy of five antibiotics on experimental airborne legionellosis in guinea-pigs

The efficacy of preventive and curative treatment of experimental airborne legionellosis in guinea-pigs was studied for erythromycin, rifampicin, minocycline, doxycycline and pefloxacin. The aerosol was produced from a strain of Legionella pneumophila serogroup 1 and dispersed in a chamber maintained below atmospheric pressure. Guinea-pigs were exposed for 30 min to 1 or 10 LD50 (10(3) or 10(4) viable inhaled organisms). Treatment was preventive or curative. Antibiotic concentrations in lungs and serum were evaluated during treatment. The action of the antibiotics on guinea-pigs infected by 1 LD50 resulted in 100% survival. For the 10 LD50 infection, pefloxacin, minocycline and erythromycin were more active (with 87.5% survivors) than doxycycline (75%) and rifampicin (62.5%). Preventive treatment with pefloxacin or doxycycline gave 100% protection, compared with 87.5% for rifampicin, 50% for erythromycin and 37.5% for minocycline. In this study, treatment of experimental legionellosis was improved, compared with previous publications, by early administration of antibiotics and increased dosage and duration.

Contribution of monocyte-macrophage system to serum alpha 1-antitrypsin

The major serum antiprotease is alpha 1-antitrypsin (A1AT). Deficiency of A1AT can result in infantile cirrhosis and premature emphysema, both of which have a high degree of morbidity and significant mortality. Although synthesized primarily by the liver, A1AT has been histochemically localized in monocytes and macrophages in vitro and has been shown to be produced in tissue culture of monocyte-macrophage origin. This study was planned to quantitatively and qualitatively assess the in vivo monocyte-macrophage system contribution to serum A1AT. We used bone marrow transplantation (BMT) as an experimental method because there is commanding evidence that after engraftment, the monocyte-macrophage system of the recipient is replaced by that of donor origin. Protease inhibitor (Pi) typing was done on 150 potential BMT recipients and on their potential donors before transplantation. From these initial recipients, 92 eventually underwent transplantation, and 11 recipient-donor pairs, in which each donor's Pi type contained a band not in the recipient's Pi type, were chosen for the study. Six recipients survived beyond 100 days after BMT, and in these cases the donor contained either an S or an M2 band in his or her Pi type not present in the recipient. Using a silver stain method on diluted serum of known M1M2 and MS types, we were able to detect a 2% dilution of the S band and a 25% dilution of the M2 band. When the same method was applied to gels used in typing recipient Pi after BMT, we were unable to detect any contribution to serum A1AT by the donor monocyte-macrophage system.

Cell-mediated and glucocorticoid-mediated target cell lysis do not appear to share common pathways

Target cell lysis by cytolyic lymphocytes follows a sequence of events that culminate in osmotic destruction of the target. Although it is clear that killer cell derived components play a crucial role in target cell lysis it is not clear to what extent the target itself is involved in its destruction. Recent observations have pointed to the possibility that glucocorticoid mediated and cell mediated lysis may utilize common pathways of cell lysis. In analyzing this question we found that cell lines that have nonfunctional glucocorticoid receptors like S49-78 and S49-88 are good targets for both NK and thymus-derived killer (TK) cells. Cell lines that are glucocorticoid sensitive such as Q1(4)6 are sensitive to NK-mediated lysis as its derivative HL4-6-3 which contains glucocorticoid receptors but is glucocorticoid resistant. An intriguing exception to this is the glucocorticoid-resistant mutant S49-4RD which is relatively resistant to both NK and TK lysis compared with parent S49. The resistance of S49-4RD to cell-mediated lysis we show here is most likely due to a defect in the target which results in its failure to trigger the cytolytic machinery in the killer cell rather than in its resistance to lysis per se. In support of this we demonstrate that lysis of S49-4RD by cytolytic granules from TK cells is normal. Moreover TK cells lyse S49-4RD as efficiently as its parent in the presence of the lectin Con A. The conclusion that S49-4RD has a defect in its ability to induce killer cells to initiate the cytolytic reaction is also in agreement with the finding that TK-S49-4RD conjugates show inefficient reorientation of the Golgi apparatus in the effector.

Cell-mediated and glucocorticoid-mediated target cell lysis do not appear to share common pathways

Target cell lysis by cytolyic lymphocytes follows a sequence of events that culminate in osmotic destruction of the target. Although it is clear that killer cell derived components play a crucial role in target cell lysis it is not clear to what extent the target itself is involved in its destruction. Recent observations have pointed to the possibility that glucocorticoid mediated and cell mediated lysis may utilize common pathways of cell lysis. In analyzing this question we found that cell lines that have nonfunctional glucocorticoid receptors like S49-78 and S49-88 are good targets for both NK and thymus-derived killer (TK) cells. Cell lines that are glucocorticoid sensitive such as Q1(4)6 are sensitive to NK-mediated lysis as its derivative HL4-6-3 which contains glucocorticoid receptors but is glucocorticoid resistant. An intriguing exception to this is the glucocorticoid-resistant mutant S49-4RD which is relatively resistant to both NK and TK lysis compared with parent S49. The resistance of S49-4RD to cell-mediated lysis we show here is most likely due to a defect in the target which results in its failure to trigger the cytolytic machinery in the killer cell rather than in its resistance to lysis per se. In support of this we demonstrate that lysis of S49-4RD by cytolytic granules from TK cells is normal. Moreover TK cells lyse S49-4RD as efficiently as its parent in the presence of the lectin Con A. The conclusion that S49-4RD has a defect in its ability to induce killer cells to initiate the cytolytic reaction is also in agreement with the finding that TK-S49-4RD conjugates show inefficient reorientation of the Golgi apparatus in the effector.

An electron microscopy study of Legionella pneumophila after in vitro and in vivo culture

The ultrastructure of Legionella pneumophila serogroup 1 (Philadelphia Strain) was studied by Scanning Transmission Electron Microscopy (STEM) following in vitro and in vivo culture. The results obtained were identical for all the samples tested; the structure belonged to the prokaryotic type, with features consistent with the known structure of Gram-negative rods. A characteristic feature is the loose undulated outer membrane, a peptidoglycan layer which was difficult to visualize and was better seen in lysed bacteria. The outermost layer was stained by ruthenium red for polysaccharides. In guinea-pig lung tissue and in chick embryo yolk sac membranes, the bacteria were more often intracellular in intracytoplasmic ribosome-studded vacuoles.

Efficacy of spiramycin on experimental airborne legionellosis in guinea pigs

The effect of preventive and curative spiramycin therapy was studied in guinea pigs infected by aerosol with the experimental model previously tested. The infectious aerosol was obtained from a virulent strain of Legionella pneumophila (Philadelphia ATCC 33 152). Male guinea pigs (Dunkin-Hartley) weighing 250-300 g were exposed for 30 min to an aerosol of 1 or 10 LD50 (10(3) or 10(4) viable inhaled organisms). Spiramycin was administered intraperitoneally (150 mg/kg/day) 18 h after infection for five days for curative therapy; for preventive therapy it was administered on the day before and on the day of aerosol administration (10 LD50). The animals were observed during seven days for weight and temperature and 28 days for survival; bacterial (lungs, spleen) and serological tests were performed. Spiramycin levels (lungs, serum) were evaluated during treatment by a microbiological method. The survival rate in the treated guinea pigs after inhalation of 1 LD50 was 100%. For the 10 LD50 aerosol, curative and preventive therapy gave a survival rate of 87.5%; these results are significant when compared with results of non-treated animals, P less than 0.05. Spiramycin merits further study in experimental and human legionellosis.

[Doxycycline treatment of experimental legionellosis in guinea pigs infected by aerosol]

The efficacy of curative and preventive treatment by doxycyclin was studied with the same experimental model as during the study of erythromycin [14]. The infectious aerosol was done with a strain of Legionella pneumophila serogroup 1, Philadelphia (ATCC 33152). Male albinos Dunkin-Hartley guinea-pigs were exposed for 30 min to an aerosol dose of 1, 10 or 100 LD 50 (10(3), 10(4) or 10(5) viable organisms). After preliminary assays to find out the efficient posology, doxycyclin was administered intraperitoneally (IP) 18 h after the infection at a dosage of 60 mg/kg/day for 5 days in the animals infected with 1 LD 50, and 75 mg/kg/day in the animals with 10 and 100 LD 50. The preventive treatment (75 mg/kg/day) administered one day before and the day of the infection was tested with animals infected with 10 LD 50. The guinea-pigs were observed 8 days (weight, rectal temperature) and watched over 3 weeks after the end of treatment; serological and bacteriological tests (cardiac blood, lungs, spleen) were performed in every animal; doxycyclin assays (serum, lungs) during treatment were performed by high performance liquid chromatography (HPLC). The treatment of guinea-pigs infected by 1, 10 and 100 LD 50 gave a survival rate of 100%, 75% and 50% respectively. On the other hand the animals which received preventive treatment were all survivors. Seroconversions with antibody titres from 64 to 512 were observed for all the survivors. Bacteriological tests were all negative. The mean doxycyclin concentrations in serum (microgram/ml) and lung (microgram/g) were 1.66 and 11.42 after 24 h of treatment and 5.71 and 18.93 after 7 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of culture medium on morphology and virulence of Legionella pneumophila serogroup 1

In a preliminary study, the preparation of a modified charcoal yeast extract by predialysis of yeast extract (CDYE) allowed us to obtain short non filamentous forms of Legionella pneumophila ser 1 (Philadelphia) found to be more virulent in the chick embryo than the long forms grown on conventional media. We confirmed these findings in guinea pigs inoculated by either intraperitoneal injection or aerosol inhalation. LD50s were calculated using the method of Reed and Muench. Survival curves were established using Liddell's method. If for chick embryo the most virulent organisms were those derived from yolk sac culture, organisms grown on CDYE agar were more virulent than those grown on the other media. There was a significant positive correlation between the mean length of the bacilli and the log 10 of the LD50 (r = 0.96; 0.02 less than p less than 0.05). For guinea pigs by either intraperitoneal injection or inhalation we confirmed that the bacteria cultured on CDYE were more virulent than those grown on other solid media. Thus for the guinea pig inoculated intraperitoneally, the LD50s of the CDYE and BCYE cultures were 1.4 X 10(7) and greater than 3 X 10(9) CFU, respectively. The mortality of guinea pigs inoculated by aerosol with CDYE cultures was significantly higher than that of guinea pigs infected with BCYE cultures using suspensions of 10(8) and 10(9) CFU/ml (p less than 0.01) and 10(10) CFU/ml (p less than 0.05).

Epidemiological evidence of legionellosis transmission through domestic hot water supply systems and possibilities of control

The use of epidemiological markers for a survey is essential because of the ubiquity of legionellae, particularly L. pneumophila serogroup (SG) 1. The two settings under study were an administrative building associated with a fatal Legionnaires' Disease (LD) case due to L. pneumophila SG 1, and a hospital with 11 cases due to L. pneumophila SG 1 and 3 cases due to L. anisa. Monoclonal antibody serotyping allowed us to establish a link between the outbreaks of LD and the contamination of the hot water supply systems. Two subtypes of L. pneumophila SG 1 and L. anisa were detected in the hospital water system. However the finding of only one subtype of L. pneumophila SG 1 in the patients raised the problem of the difference in virulence of each Legionella strain. By means of aerosol tests on normal and cyclophosphamide-immunosuppressed guinea pigs, we demonstrated the potential pathogenicity of hospital water in the immunosuppressed animals. Two decontamination methods were applied: chlorination and a rise in hot water temperature. Time-limited control measures in the hospital were inadequate, resulting in only temporary eradication, followed by a rapid recolonization of legionellae and the appearance of new nosocomial cases. Decontamination of the administrative building was found to be effective when a constant concentration of 5 ppm free chlorine was obtained at tap outlets, and the water temperature was maintained at 55 C.

[Treatment with erythromycin of experimental legionellosis in guinea pigs infected by aerosol]

The infectious strain L. pneumophila serogroup 1 Philadelphia (ATCC 33152) was cultured on charcoal dialysed yeast extract agar medium (CDYE agar) which produces more virulent strains than those grown on classical agar media. The aerosol was dispersed in a depression chamber by means of a nebuliser and the density was controlled by a density probe. Male albinos Dunkin-Hartley guinea pigs weighing 250-300 g were exposed for 30 minutes to an aerosol dose of 1 LD50 (10(3) viable organisms) and 10 LD50 (10(4) viable organisms). Erythromycin lactobionate (Abbott) was administered subcutaneously 18 hours after the infection, at dosages of 270 mg/kg/day for 4 days in the animals treated with 1 LD50 and for 6 or 7 days in the animals treated with 10 LD50. The guinea pigs were observed for 9 days (weight, rectal temperature; serological and bacteriological tests (cardiac blood, lungs, spleen) and erythromycin assays (serum, lungs) were performed and compared in the treated animals, the non-treated infected control animals and the control animals which only received erythromycin. The percentage survival in the treated guinea pigs after inhalation of 1 LD50 and 10 LD50 (2 tests) were 100%, 75% and 87.5% respectively. Three weeks after treatment, the survivors had antibody titres from 32 to 1,024; the bacteriological cultures and erythromycin assays were negative. In this study, an improvement in the treatment of experimental Legionnaires' disease was observed in comparison with previous experiments. The increased dosage and duration and the early initiation of treatment resulted in survival rates of 75%.(ABSTRACT TRUNCATED AT 250 WORDS)