MHC class II-dependent NK1.1+ gammadelta T cells are induced in mice by Salmonella infection

We observed the emergence of a novel population of gammadelta T cells expressing NK1.1 Ag in the peritoneal cavity of mice infected with Salmonella choleraesuis. The NK1.1+gammadelta T cells accounted for approximately 20% of all gammadelta T cells emerging in the peritoneal cavity of C57BL/6 mice and expressed preferentially rearranged Vgamma4-Jgamma1 and Vdelta6.3-Ddelta1-Ddelta2-Jdelta1 genes with N diversity. The gammadelta T cells proliferated vigorously in response to PHA-treated spleen cells and produced IFN-gamma in the culture supernatant. However, spleen cells from Abetab-deficient mice were unable to stimulate the gammadelta T cells. Furthermore, the NK1.1+gammadelta T cells were stimulated not only by Chinese hamster ovary (CHO) cells expressing wild-type IAb but also by those expressing IAb/Ealpha52-68 or IAb/pigeon cytochrome c-derived analogue peptide complex. These proliferation activities were inhibited by mAb specific for IAb chain. Consistent with these findings, the emergence of NK1.1+gammadelta T cells was reduced in the peritoneal cavity of Abetab-deficient mice after Salmonella infection, whereas NK1.1+gammadelta T cells were rather abundant in the peritoneal cavity of Salmonella-infected beta2m-deficient mice. Moreover, the NK1.1+gammadelta T cells were easily identified in the thymus of beta2m-deficient but not Abetab-deficient mice. Our results indicated that MHC class II expression is essential for development and activation of NK1. 1+gammadelta T cells in the thymus and the periphery.     

Immunization with E. coli produced recombinant T. gondii SAG1 with alum as adjuvant protect mice against lethal infection with Toxoplasma gondii

Polyclonal rabbit antibodies against recombinant Toxoplasma gondii SAG1 antigen expressed in E.coli recognize T. gondii and the antibodies significantly reduced T.gondii adherence and/or invasion into the host cell as did a monoclonal antibody against a conformational epitope of the SAG1 antigen. Groups of outbread NMRI mice were immunized with recombinant T. gondii SAG1 antigen in alum. The antibody response to immunizations was dominated by a Th2 response with production of T.gondii specific IgG1 antibodies. Challenge with tachyzoites from the virulent RH-strain produced a Th1 response dominated by the production of specific IgG2a antibodies and moderately boosted the IgG1 response, and challenge with bradyzoites from the avirulent SSI119-strain showed the same pattern. Immunization with rSAG1 resulted in a significant increased survival after challenge with tachyzoites of the RH-strain. Immunization with E.coli expressed recombinant SAG1 in alum induce partial protective immunity against lethal infection with T. gondii in mice.     

Peritoneal gamma delta T cells induced by Escherichia coli infection in mice. Correlation between Thy-1 phenotype and host minor lymphocyte-stimulating phenotype

We found that gamma delta T cells increased in number in the peritoneal cavity after i.p. inoculation with Escherichia coli (ATCC 26) in mice. The increase of the gamma delta T cells was most prominent on day 5 after inoculation when the pathogens had been already eliminated from the hosts. Two-color flow cytometric (FCM) analysis revealed that these gamma delta T cells in infected C57BL/6 mice expressed Thy-1 Ag on their cell surface. On the other hand, gamma delta T cells induced by E. coli inoculation in C3H/He mice contained Thy-1-negative gamma delta T cells in addition to the Thy-1-positive gamma delta T cells. In both strains, irrespective of Thy-1 Ag expression, these gamma delta T cells were CD5 negative, CD44 positive, L-selectin negative, Ly-6C negative, and IL-2R low positive. Analyses of peritoneal exudate cells (PEC) from several other strains of mice after E. coli inoculation suggested that Thy-1-negative gamma delta T cells appear in mice carrying endogenous superantigen specific for V beta 3, especially mammary tumor virus-6. These findings suggest that Thy-1 Ag expression on the gamma delta T cells appearing in the peritoneal cavity after i.p. E. coli inoculation is correlated to the Mls phenotype of the host mice.     

Gene knockout B cell-deficient mice demonstrate that B cells play an important role in the initiation of T cell responses to Chlamydia trachomatis (mouse pneumonitis) lung infection

T cell-mediated immunity as measured by delayed-type hypersensitivity, and IFN-gamma production has been shown to be critical for host defense against Chlamydia trachomatis infection in both human and animal studies. Using gene-targeted B cell-deficient mice, we examined the role of B cells in protective immunity to C. trachomatis (mouse pneumonitis) (MoPn) lung infection. B cell-deficient mice were observed to have a significantly higher mortality rate and in vivo chlamydial growth than did wild-type mice following MoPn lung infection. Interestingly, B cell-deficient mice not only lacked Ab responses but also failed to mount an efficient delayed-type hypersensitivity response following chlamydial lung infection. In contrast to results obtained from MoPn-infected wild-type C57BL/6 mice, spleen cells from infected B cell-deficient mice failed to produce Th1-related (IFN-gamma) or Th2-related (IL-6 and IL-10) cytokines after Chlamydia-specific in vitro restimulation. Moreover, unlike wild-type mice, B cell-deficient mice were not immune to rechallenge infection following recovery from primary chlamydial infection. The data indicate that B cells play an important role in host defense to primary and secondary chlamydial infection and suggest that B cells are crucial for the initiation of early T cell responses to chlamydial infection. This study provides evidence for the role of B cells in the in vivo priming of T cells during infection with the intracellular bacterial pathogen, C. trachomatis.     

Evidence for the involvement of interleukin 10 in the differential deactivation of murine peritoneal macrophages by prostaglandin E2

Among other effects, prostaglandins (PG) of the E series are known to inhibit several acute and chronic inflammatory conditions in vivo and proinflammatory cytokine production by activated macrophages in culture. The research presented here demonstrates that the inhibitory effect of PGE2 on tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) production by lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages involves IL-10. In a dose-dependent manner, PGE2 inhibits LPS-induced release of TNF-alpha and IL-6, but not of lactate or nitric oxide. The decrease in the level of these cytokines is inversely proportional to the increase in immunoreactive IL-10. This differential inhibitory effect of PGE2 is mimicked by agents that elevate intracellular levels of cAMP, but not cGMP. Neutralizing anti IL-10 antibody but not neutralizing antibodies against other macrophage secretory products (IL-6, leukemia inhibitory factor, and transforming growth factor beta [TGF-beta]), significantly reverse the potent inhibitory effect of PGE2. In vivo, the administration of PGE2 before LPS challenge significantly reduces circulating TNF-alpha and IL-6 levels. Anti-IL-10 antibody substantially enhanced the LPS-induced TNF-alpha and IL-6 levels in mice that received either LPS alone or LPS plus PGE2. These results suggest that the anti-inflammatory effect of PGE2 on mononuclear phagocytes is mediated in part by an autocrine feedback mechanism involving IL-10.     

Interleukin-6 production in human fibroblasts derived from periodontal tissues is differentially regulated by cytokines and a glucocorticoid

Interleukin-6 (IL-6) is thought to be a major mediator of the host's defense against infection, and it regulates immune responses in inflamed tissue. In this study, we investigated the regulation of IL-6 production in human gingival fibroblasts (HGF) and human periodontal ligament fibroblasts (HPLF). Pro-inflammatory cytokines including interleukin (IL)-1 alpha, IL-1 beta and tumor necrosis factor (TNF)-alpha stimulated IL-6 production in HGF and HPLF in a time- and dose-dependent manner. This IL-1 alpha, IL-1 beta, or TNF-alpha-induced IL-6 production was enhanced, but the cAMP accumulation they induced was inhibited by the addition of indomethacin. This result suggests that endogenous prostaglandin E2 (PGE2) partially inhibits IL-1 or TNF-alpha-induced IL-6 production and that the enhancement of IL-6 production by IL-1 or TNF-alpha may not be caused through endogenous PGE2-induced cAMP-dependent pathway. Dexamethasone (DEX), a glucocorticoid which is a inhibitor of nuclear factor kappa B (NF-kappa B activation, markedly inhibited IL-1 (alpha or beta) or TNF-alpha-induced IL-6 production; so this production may be partially mediated through NF-kappa B. IL-1 (alpha or beta) and TNF-alpha enhanced IL-6 production synergistically. IL-6 production in HGF or HPLF stimulated with IL-1 beta was augmented by the addition of interferon (IFN)-gamma, but was slightly suppressed by the addition of IL-4. Endogenous IL-6 enhanced IL-1 (alpha or beta)-induced IL-6 production in the presence of IL-6 soluble receptor (IL-6sR). Accordingly, in inflamed periodontal tissues, gingival fibroblasts and periodontal ligament fibroblasts stimulated with pro-inflammatory cytokines such as IL-1 or TNF-alpha, may produce IL-6, and this production can be differentially modulated by endogenous PGE2, IL-6sR, T cell-derived cytokines such as IFN-gamma or IL-4, and glucocorticoids.     

Expression and functional activity of P-glycoprotein in adult acute myelogenous leukemia patients

Stimulation of the host defense system in a nonspecific way may provide effective treatment of recurrent infections. CANTASTIM is a bacterial product that has been successfully used in cancer immunotherapy as well as in chronic infections treatment. The nonspecific protective effect of CANTASTIM was investigated in two models of experimental infection with Salmonella typhimurium in mice. Prophylactic administration of CANTASTIM (three days before challenge) enhanced peritoneal macrophages bactericidal activity and significantly increased survival of treated mice. When CANTASTIM was administered 72 h after bacterial challenge, in a sublethal infection model with Salmonella typhimurium, by activating macrophages, NK and T cells, it increased the survival rate. The cell populations and molecular mechanisms involved in the prophylactic and therapeutic protective effect CANTASTIM seem to be partially different.     

Bacterially preexposed T cells impair bacterial elimination by non-Th1/Th2 cell mechanisms in a model of intra-abdominal infection

BACKGROUND: Escherichia coli preexposure in mice results in impaired elimination of subsequent intra-abdominal infections by a CD+4 T cell-dependent process. Certain gram-negative infections have been shown to induce T-helper-(Th)2 type CD4+ T-cell differentiation, which correlates with impaired elimination of infection and death. We hypothesized that E coli preexposure impairs subsequent bacterial elimination as a consequence of Th2 differentiation and that interleukin-12 (IL-12) treatment could reverse this differentiation and minimize the effects of E coli preexposure. METHODS: After preexposure to E coli or other species, BALB/c mice or interferon-gamma (INF-gamma)-deficient mice, treated with or without IL-12, were given a standard intra-abdominal infection (E coli, Bacteroides fragilis, and adjuvant). Cohorts were killed for abscess quantification, in vitro T-cell proliferative responsiveness, and cytokine secretory profiles. Splenic lymphocytes preexposed in vivo to other types of bacteria were transferred to naive mice before intra-abdominal infection to determine whether preexposure, eliciting the lymphocyte-dependent response, was species specific. RESULTS: E coli preexposure alone caused no Th1 or Th2 shift; increased the proliferative responses of T cells; and, in combination with IL-12 therapy, caused markedly decreased IL-2 and IL-4 responses and an increased IFN-gamma response. IL-12 therapy did not change the response to intra-abdominal infection despite its ability to cause marked Th1 polarization. IFN-gamma-deficient mice responded to E coli preexposure no differently than did wild-type mice. Transfer of lymphocytes preexposed to Pseudomonas aeruginosa, Klebsiella pneumoniae, and hemolytic E coli but not other types of nosocomial pathogens caused the development of more abscesses just as transfer of E coli preexposed lymphocytes had. CONCLUSIONS: CD4+ T cells responsive to E coli preexposure regulate subsequent intra-abdominal abscess formation by a mechanism not explained by the Th1/Th2 paradigm. Preexposure to hemolytic E coli and other Enterobacteriaceae alters responses to intra-abdominal infection.     

In vitro interleukin 12 activation of peripheral blood CD3(+)CD56(+) and CD3(+)CD56(-) gammadelta T cells from glioblastoma patients

Interleukin (IL)-12 has recently been shown to be directly involved in the activation of natural killer and alphabeta T cells via an IL-2-independent pathway. We show here that another type of human cytotoxic cell, gammadelta T cells activated by solid-phase anti-CD3 antibody and expanded using IL-2, obtained, in this case, from the peripheral blood of glioblastoma patients, displays significant tumoricidal activity. In addition, its cytotoxic activity against K562 or Daudi cells or against autologous glioblastoma targets (but not lymphocytes) is significantly enhanced when costimulated with IL-2 and IL-12. To study this synergistic activation by the two interleukins of the patients' gammadelta T cells, we screened the cells for the presence of the IL-2 receptor (IL-2R) and IL-12 receptor (IL-12R) using both flow cytometric analysis and PCR. The patients' gammadelta T cells constitutively expressed the high-affinity IL-2R; when stimulated with IL-12 plus IL-2, the levels of IL-2Ralpha and IL-2Rbeta increased, whereas that of IL-2gamma did not. They also expressed marginal levels of low-affinity IL-12R both immediately after IL-2 expansion and after 24-h incubation, and significantly higher levels after 72-h incubation, consistent with the level of gammadelta T-cell activation. IL-12 alone induced little proliferation of patients' gammadelta T cells in a 24-h assay and none in a 72-h assay; however, it caused a marked inhibition of the IL-2-induced proliferative response in the 72-h assay. The synergistic action of IL-2 and IL-12 was completely abolished by combined pretreatment with anti-IL-2alpha, beta, and gamma mAbs. IL-12-mediated enhancement of gammadelta T cell cytotoxic activity was inhibited by anti-IL-2Rbeta mAb in a dose-dependent manner but not by anti-IL-2Ralpha or anti-IL-2Rgamma mAbs. Thus, the increased expression of the IL-2Rbeta is critical for the synergistic activation of gammadelta T cells by IL-12 plus IL-2; it is also probable that at least the low-affinity IL-12R contributes to the activation of gammadelta T cells mediated by either IL-12 alone or IL-12 plus IL-2. We have, therefore, demonstrated that IL-12 can stimulate the cytotoxic activity of gammadelta T cells from glioblastoma patients, acting via the IL-2Rbeta component of the IL-2R and low-affinity IL-12R. IL-12 activation of patients' gammadelta T cells could possibly be of potential use in the treatment of glioblastoma patients.     

Normal macrophage functions, but impaired induction of gamma delta T cells, at the site of bacterial infection in CD45 exon 6-deficient mice

We investigated the protective functions of macrophages and gamma delta T cells in adult CD45 exon 6-deficient (CD45 -/-) mice against an intraperitoneal (i.p.) infection with Listeria monocytogenes. gamma delta T cells are preferentially localized in the spleen, liver, and intraperitoneal cavity of the adult CD45-/- mice. Increased numbers of gamma delta T cells were observed after i.p. infection with L. monocytogenes in the peritoneal cavity of C57BL/6 (CD45 +/+) mice but not in CD45 -/- mice. The gamma delta T cells showed predominant usage of V delta 5 and V delta 6 rearranged to J delta 1 in the infected CD45 -/- mice which are the same as those used by resident gamma delta T cells of noninfected CD45 +/+ and CD45 -/- mice. Furthermore, we analyzed the protective abilities of the CD45 -/-, CD45 +/+, and gamma delta T cell-depleted mice at the early stage of the listerial infection. The numbers of bacteria in the spleens and livers of the CD45 -/- mice 5 days after the listerial infection were almost ten times larger than those in the CD45 -/- and gamma delta T cell-depleted CD45 +/+ mice. Macrophages showed normal antigen presentation, nitric oxide production and bactericidal activity for L. monocytogenes despite their lacking CD45 surface expression, suggesting that CD45-negative macrophages have a minimal influence on the increased bacterial multiplication in the CD45-/- mice. These results suggest that the gamma delta T cells are induced by the bacterial infection in a CD45-dependent manner, and that unresponsiveness of the gamma delta T cells results in only weak protection against L. monocytogenes in CD45 -/- mice.     

High-performance liquid chromatographic analysis of chlorhexidine in saliva after mouthrinsing

BACKGROUND: Neutrophils contribute to the host defense mechanism, but they can cause remote organ injury in peritonitis. The purpose of this study was to examine neutrophil adhesion to the peritoneum and remote organs simultaneously in peritonitis using a fluorescence microscopic method. STUDY DESIGN: Experiment 1: Sprague-Dawley rats (n = 16) were injected intraperitoneally (ip) with saline solution or 10(5), 10(7), or 10(9) Escherichia coli. Five hours after challenge, 1 x 10(6) fluorescein-labeled neutrophils were infused. Two minutes after neutrophil injection, five peritoneal samples (the greater omentum, mesentery, parietal peritoneum, colon, and ileum), both lungs, the liver, and the right kidney were harvested for counting of labeled neutrophils under epifluorescent microscopy. Lung myeloperoxidase (MPO) activity was also determined. Experiment 2: Rats (n = 23) were given 10(9) E. coli ip. Before challenge (0 h) or at 1, 5, or 10 h after challenge, labeled neutrophils were infused. Then, the labeled neutrophil numbers in organs and lung MPO activities were assessed as described for Experiment 1. Hemodynamic and arterial blood gas data were also obtained in another set of rats before and at 1, 5, 8 and 10 h after 10(9) E. coli ip challenge. RESULTS: Experiment 1: The labeled neutrophil numbers in the peritoneum, lungs, and kidney showed significant positive correlations with the injected bacterial numbers. Lung MPO also positively correlated with E. coli number and labeled neutrophil number in the lungs. Experiment 2: Labeled neutrophil numbers in the peritoneum and kidney peaked at 5 h. The pulmonary labeled neutrophil number rose, reaching a plateau at 5 h. No remarkable change was observed in the hepatic labeled neutrophil number. There was a positive correlation between lung MPO activity and pulmonary labeled neutrophil number. Hemodynamic and blood gas data reflected a hyperdynamic state. CONCLUSIONS: Concomitant dose-dependent increases in neutrophil adhesion in the peritoneum, lungs, and kidney were observed in this peritonitis model. Increased neutrophil adhesion was transient in the peritoneum and kidney but persistent in the lungs. Strategies modulating neutrophil adhesion in organs are anticipated to be useful for the treatment of peritonitis.     

Safety evaluation of a polymerized hemoglobin solution in a murine infection model

Several investigators have observed that free hemoglobin may increase the mortality rate in experimental Escherichia coli peritonitis in animals. This effect is probably mediated by the heme moiety of hemoglobin, but the mechanism remains controversial. Free hemoglobin might impair neutrophil function, and it might serve as a source of iron, which is necessary for bacterial replication. Several modified hemoglobin solutions, developed as blood substitutes, are currently being tested in clinical studies, but concern exists that these solutions may have the potential to exacerbate a bacterial infection. At the Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, a blood substitute based on modified hemoglobin (PolyHbXl) has been developed that has improved oxygen affinity and prolonged vascular retention. In the present study the potential risk of this solution on the promotion of infections has been evaluated. PolyHbXl was intravenously injected into mice in a clinically relevant dose of 1.5 gm/kg body weight 1 hour before intravenous administration of a sublethal number of Listeria monocytogenes, Salmonella typhimurium, E. coli, or Candida albicans organisms. PolyHbXl did not promote the proliferation of any of these microorganisms in the liver and spleen, nor did it lead to an increased mortality rate in the mice. Also, the in vitro proliferation of L. monocytogenes, S. typhimurium, and E. coli was not increased by PolyHbXl. In conclusion, PolyHbXl does not affect the course of infection with various microorganisms in mice, and no indication was found that this new blood substitute compromises the host defense against infections.     

Prostaglandin E2 primes naive T cells for the production of anti-inflammatory cytokines

In addition to their capacity to induce pain, vasodilatation and fever, prostaglandins E (PGE) exert anti-inflammatory activities by inhibiting the release of pro-inflammatory cytokines by macrophages and T cells, and by increasing interleukin (IL)-10 production by macrophages. We here report that PGE2, the major arachidonic acid metabolite released by antigen-presenting cells (APC), primes naive human T cells for enhanced production of anti-inflammatory cytokines and inhibition of pro-inflammatory cytokines. Unfractionated as well as CD45RO- CD31+ sort-purified neonatal CD4 T cells acquire the capacity to produce a large spectrum of cytokines after priming with anti-CD3 and anti-CD28 monoclonal antibodies (mAb), in the absence of both APC and exogenous cytokines. PGE2 primes naive T cells in a dose-dependent fashion for production of high levels of IL-4, IL-10 and IL-13, and very low levels of IL-2, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and TNF-beta. PGE2 does not significantly increase IL-4 production in priming cultures, whereas it suppresses IL-2 and IFN-gamma. Addition of a neutralizing mAb to IL-4 receptor in primary cultures, supplemented or not with PGE2, prevents the development of IL-4-producing cells but does not abolish the effects of PGE2 on IL-10 and IL-13 as well as T helper (Th)1-associated cytokines. Addition of exogenous IL-2 in primary cultures does not alter the effects of PGE2 on naive T cell maturation. Thus PGE2 does not act by increasing IL-4 production in priming cultures, and its effects are partly IL-4 independent and largely IL-2 independent. Together with the recent demonstration that PGE2 suppresses IL-12 production, our results strongly suggest that this endogenously produced molecule may play a significant role in Th subset development and that its stable analogs may be considered for the treatment of Th1-mediated inflammatory diseases.     

Cosmetic results of breast conserving therapy for breast carcinoma. Treatment results from the Heidelberg Radiation Clinic in the years 1984 to 1992]

We examined the effect of an antioxidant and protein kinase inhibitors on prostaglandin E2 (PGE2) release from Balb/c 3T3 mouse fibroblast cells induced by quinolone phototoxicity. Simultaneous administration of sparfloxacin (SPFX) or lomefloxacin (LFLX) at 12.5 to 100 microM and ultraviolet-A (UVA) irradiation for 10 min markedly elevated PGE2 concentration in the incubation medium, whereas levofloxacin (LVFX) at concentrations up to 100 microM and UVA irradiation did not increase PGE2 concentration. Pretreatment with 100 microM pyrrolidine dithiocarbamate (PDTC), an antioxidant, or 1 microM calphostin C, a selective inhibitor of protein kinase C (PKC), completely inhibited the elevation of PGE2 in the 24-h incubation medium; pretreatment with 10 microM H7, a cyclic nucleotide-dependent protein kinase, and PKC or 1 microM herbimycin A, a tyrosine kinase inhibitor, inhibited the PGE2 elevation by 29 to 39%. Conversely, 25 nM staurosporine significantly augmented the PGE2 elevation by quinolones plus UVA. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) were not detected in the incubation medium of 3T3 cells after quinolone plus UVA, corresponding to the lack of effect of antibodies against IL-1alpha, IL-1beta, and TNFalpha on PGE2 release from 3T3 cells. These results suggest that PGE2 production in 3T3 cells by quinolone phototoxicity is modulated by reactive oxygen species, PKC, and tyrosine kinase, but not by IL-1 or TNFalpha.     

Amelioration of collagen-induced arthritis and suppression of interferon-gamma, interleukin-12, and tumor necrosis factor alpha production by interferon-beta gene therapy

Human Vgamma9Vdelta2 T cells contribute to immunity against intracellular pathogens and recognize nonpeptidic antigens, such as the mycobacterial phosphoantigen TUBAg. HIV infection is associated with a polyclonal decrease of peripheral Vgamma9Vdelta2 T cells and we previously reported that the remaining cells show a proliferative anergy to stimulation with Mycobacterium tuberculosis in 60% of patients. Because of alterations in the Th1/Th2 cytokine balance reported in HIV infection, we analyzed, at the single-cell level, the influence of exogenous IL-4, IL-10, IL-12 and IL-15 on the response to mycobacterial phosphoantigens of gammadelta T cells from HIV-infected patients and healthy donors. We report that the strong gammadelta T cell response to TUBAg is characterized by the rapid and selective production of the Th1/proinflammatory cytokines IFN-gamma and TNF-alpha in responder HIV-infected donors. In addition, a positive regulation by IL-12 and IL-15 of the production of these cytokines by Vgamma9Vdelta2 T cells in response to nonpeptidic ligands was observed, whereas IL-4 and IL-10 had no effect. In contrast, Vgamma9Vdelta2 T cells from the anergic HIV-infected donors had lost the ability to produce Th1 cytokines and were not shifted towards a Th2 profile. Furthermore, neither IL-12 nor IL-15 could reverse this functional anergy. The consequences of these observations are discussed in the context of HIV pathogenesis.     

Suppression of the granulocyte colony-stimulating factor response to Escherichia coli challenge by alcohol intoxication

Alcohol's suppressive effects on polymorphonuclear leukocyte (PMN) production and function increases host susceptibility to a wide variety of infections and impairs the ability of these effector cells to seek and destroy invading pathogens. Granulocyte colony-stimulating factor (G-CSF), an important regulator of PMN production and function, is known to be increased in the plasma during infectious episodes. In previous studies we found acute alcohol intoxication to suppress the tumor necrosis factor-alpha (TNF alpha) response to in vivo challenges with bacteria or lipopolysaccharide. The present study was initiated to determine the impact of alcohol intoxication on the plasma G-CSF response to gram-negative infection. For this purpose, rats received an intravenous challenge of Escherichia coli (10(6) CFU) 30 min after an intraperitoneal injection of ethanol (5.5 g/kg) or an equivalent volume of saline (control). Ethanol-intoxicated rats had a greater 48 hr mortality to live E. coli injection than did unintoxicated animals (45% vs. 8%). Despite an increased bacterial burden in both the lung and liver at 24 hr after initiating E. coli infection in alcohol-intoxicated animals, PMN tissue recruitment, indexed as myeloperoxidase activity, did not differ between control and alcohol-treated rats. Moreover, alcohol suppressed blood PMN phagocytic capacity to a greater extent in animals given alcohol than controls at 5 and 24 hr after initiating infection. In control animals after intravenous E. coli injection, bioactive G-CSF increased in plasma and peaked near 300 ng/ml at 8 hr. In rats pretreated with alcohol, the plasma G-CSF response was markedly suppressed in response to intravenous E. coli (p < 0.05). In a second experiment, neutralization of the E. coli-induced plasma TNF alpha response by pretreatment with anti-TNF alpha antibody similarly inhibited the plasma G-CSF response. These results support the postulate that alcohol-induced inhibition of TNF alpha directly contributes to the adverse effects of alcohol on PMN function by suppressing the normal autocrine amplification pathway responsible for G-CSF production.     

A spontaneous induction of fetal membrane prostaglandin production precedes clinical labour

Fetal membranes from term human pregnancies produce prostaglandins, and may respond to bacterial endotoxin or interleukin-1 beta (IL-1 beta) with increased prostaglandin E2 (PGE2) production. The effects of endotoxin persisted for up to 24 h, whereas those of IL-1 beta were maximal 4-8 h after addition. The maximum levels of PGE2 (200-350 pg/ml) were similar in all experiments, and were independent of the stimulus used. Not all tissues responded to these stimuli; those which did not had basal levels of PGE2 production of 200-350 pg/ml, which was not further increased by endotoxin or IL-1 beta. The basal production from these tissues was therefore similar to the maximal production from those tissues which responded to endotoxin or IL-1 beta. The high basal production of PGE2 was attributed to prior in vivo activation of the membranes such that PGE2 synthesis could not be further stimulated in vitro. Overnight pretreatment with aspirin decreased basal PGE2 production from these activated membranes to < 100 pg/ml/4 h during subsequent culture in aspirin-free medium. Both endotoxin and IL-1 beta increased PGE2 production from the activated aspirin-pretreated membranes during this culture time, but this was transient as after 12 h of culture basal PGE2 production rose to over 200 pg/ml despite aspirin pretreatment.     

Marked eosinophilia in interleukin-5 transgenic mice fails to prevent Trichinella spiralis infection

In order to study the role of eosinophils in the host defense against Trichinella spiralis infection, worm recovery after infection with T. spiralis was compared between interleukin-5 transgenic (IL-5 Tg) mice with a constant high level of peripheral eosinophils and nontransgenic C3H/HeN mice. No significant difference in the recovery of muscle larvae or adult worms in the small intestine, fecundity of female adult worms, or infectivity of newborn larvae was observed between nonimmunized C3H/HeN and IL-5 Tg mice or C3H/HeN and IL-5 Tg mice immunized with somatic antigen of T. spiralis. However, a significant difference was observed in the fecundity of female adult worms and recovery of muscle larvae between nonimmunized and immunized IL-5 Tg mice or C3H/HeN mice. These results demonstrate that having more eosinophils does not improve immunity against the various aspects of T. spiralis infection.     

Review: immunobiology of preeclampsia

Nitric oxide (NO) is a regulator of leukocyte adhesion in the microcirculation. This study was designed to examine the effects of a NO synthase inhibitor on neutrophil adhesion in the peritoneum, lung, liver, and kidney in a rat peritonitis model using a fluorescence microscopic method. Sprague-Dawley rats were given normal saline (control) or N omega-nitro-L-arginine methyl ester (L-NAME) at dosages of 10 mg/kg (N10) or 100 mg/kg (N100) (n = 66) intraperitoneally. One hour after pretreatment fluorescein-labeled neutrophils were infused without bacterial challenge (0 hr). Other rats received an injection of 10(7) Escherichia coli into the peritoneal cavity 1 hr after pretreatment. Labeled neutrophils were infused 1 and 5 hr after bacterial challenge. Just 2 min after neutrophil injection, blood samples were obtained and the animals were killed. Five peritoneal samples (omentum, mesentery, parietal peritoneum, colon, and ileum), both lungs, the liver, and the right kidney were harvested for counting of labeled neutrophils under epifluorescent microscopy. Combined plasma nitrite/nitrate levels were determined. In another set of rats (n = 36), an arterial catheter was inserted after L-NAME treatment and bacterial challenge. At 0, 1, 5, and 12 hr after challenge, blood pressure, heart rate, and arterial blood gas data were measured. One hour after E. coli challenge, the number of neutrophils in the peritoneum was significantly lower in both L-NAME-treated groups than in the control group. In contrast, the number of labeled neutrophils in the lungs was significantly higher in the N100 group than in the control group. Neutrophil accumulation in the lungs and peritoneum at 0 and 5 hr and in the liver and kidney at 0, 1, and 5 hr did not differ among groups, nor did combined plasma nitrite/nitrate levels. L-NAME treatment had no influence on either hemodynamic or blood gas data. In conclusion, administration of L-NAME increases neutrophil adhesion in the lung, while decreasing that in the peritoneum. NO plays an important role in neutrophil adhesion at the inflammatory site, as well as in remote organs, during peritonitis. NO inhibition may be detrimental, due to neutrophil sequestration, in this peritonitis model.